WO1999032604A1 - Linoleate isomerase - Google Patents

Linoleate isomerase Download PDF

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Publication number
WO1999032604A1
WO1999032604A1 PCT/US1998/027612 US9827612W WO9932604A1 WO 1999032604 A1 WO1999032604 A1 WO 1999032604A1 US 9827612 W US9827612 W US 9827612W WO 9932604 A1 WO9932604 A1 WO 9932604A1
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WIPO (PCT)
Prior art keywords
seq
nucleic acid
linoleate isomerase
isomerase
acid molecule
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PCT/US1998/027612
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English (en)
Inventor
Reinhardt A. Rosson
Alan D. Grund
Ming-De Deng
Fernando Sanchez-Riera
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Dcv, Inc. Doing Business As Bio-Technical Resources
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Priority to JP2000525523A priority Critical patent/JP2002508929A/ja
Priority to AU20150/99A priority patent/AU2015099A/en
Priority to EP98964935A priority patent/EP1042451A4/fr
Publication of WO1999032604A1 publication Critical patent/WO1999032604A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
    • C12P7/00—Preparation of oxygen-containing organic compounds
    • C12P7/64—Fats; Fatty oils; Ester-type waxes; Higher fatty acids, i.e. having at least seven carbon atoms in an unbroken chain bound to a carboxyl group; Oxidised oils or fats
    • C12P7/6409—Fatty acids
    • C12P7/6427—Polyunsaturated fatty acids [PUFA], i.e. having two or more double bonds in their backbone
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
    • C12N11/00—Carrier-bound or immobilised enzymes; Carrier-bound or immobilised microbial cells; Preparation thereof
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
    • C12N11/00—Carrier-bound or immobilised enzymes; Carrier-bound or immobilised microbial cells; Preparation thereof
    • C12N11/02—Enzymes or microbial cells immobilised on or in an organic carrier
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
    • C12N9/00—Enzymes; Proenzymes; Compositions thereof; Processes for preparing, activating, inhibiting, separating or purifying enzymes
    • C12N9/90—Isomerases (5.)
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
    • C12P7/00—Preparation of oxygen-containing organic compounds
    • C12P7/64—Fats; Fatty oils; Ester-type waxes; Higher fatty acids, i.e. having at least seven carbon atoms in an unbroken chain bound to a carboxyl group; Oxidised oils or fats
    • C12P7/6409—Fatty acids
    • C12P7/6427—Polyunsaturated fatty acids [PUFA], i.e. having two or more double bonds in their backbone
    • C12P7/6431—Linoleic acids [18:2[n-6]]
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
    • C12P7/00—Preparation of oxygen-containing organic compounds
    • C12P7/64—Fats; Fatty oils; Ester-type waxes; Higher fatty acids, i.e. having at least seven carbon atoms in an unbroken chain bound to a carboxyl group; Oxidised oils or fats
    • C12P7/6436—Fatty acid esters
    • C12P7/6445—Glycerides
    • C12P7/6472—Glycerides containing polyunsaturated fatty acid [PUFA] residues, i.e. having two or more double bonds in their backbone
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12Y—ENZYMES
    • C12Y502/00—Cis-trans-isomerases (5.2)
    • C12Y502/01—Cis-trans-Isomerases (5.2.1)
    • C12Y502/01005—Linoleate isomerase (5.2.1.5)

Definitions

  • the present invention relates to an isolated linoleate isomerase enzyme, an nucleic acid molecule encoding a linoleate isomerase enzyme, to immobilized cells containing a linoleate isomerase enzyme, and to a method for converting linoleic acid or linolenic acid to CLA using the isolated linoleate isomerase enzyme, nucleic acid molecule and/or immobilized cells.
  • CLA is used herein as a generic term to describe both conjugated linoleic acid and conjugated linolenic acid.
  • the CLA compounds (cis,trans)-9,ll- linoleic acid and (trans,cis)-10,12-linoleic acid are recognized nutritional supplements and effective inhibitors of epidermal carcinogenesis and forestomach neoplasia in mice, and of carcinogen-induced rat mammary tumors.
  • CLA has also been shown to prevent adverse effects caused by immune stimulation in chicks, mice and rats, and has been shown to decrease the ratio of low density lipoprotein cholesterol to high density lipoprotein cholesterol in rabbits fed an atherogenic diet.
  • CLA also reduces body fat in mouse, rat, chick and pig models.
  • CLA has also been shown to be effective in treating skin lesions when included in the diet.
  • CLA occurs naturally in various amounts in virtually all foods.
  • the principle natural sources of CLA are dairy products, beef and foods derived from ruminant animals.
  • beef, beef tallow, veal, lamb (3-4 mg CLA/g fat; 84% cis-9, trans-11) and dairy products (3-7 mg CLA/g fat; 80-90% cis-9, trans-11) have the highest concentration of CLA.
  • CLA concentrations 2-3 times higher are found in Australian dairy products and pasture-fed beef and lamb.
  • Very low concentrations of CLA 0.1-0.7 mg CLA/g fat; ca. 40% each cis-9, trans-11 and trans-10, cis-12 are found in commercial vegetable oils.
  • CLA is a normal intermediate of linoleic acid metabolism.
  • (cis,trans)- 9,11-CLA produced by natural bacterial flora that is not further metabolized is incorporated into lipids and then into host tissues and milk.
  • Animals take up and incorporate CLA into normal tissue and milk from dietary sources such as milk, milk products or meat containing CLA, or from CLA dietary supplements.
  • CLA can be synthetically obtained from alkaline isomerization of linoleic or linolenic acid, or of vegetable oils which contain linoleic acid, linolenic acid or their derivatives.
  • Heating vegetable oil at about 180°C under alkaline conditions catalyzes two reactions: (1) fatty acid ester bonds from the triglyceride lipid backbone are hydrolyzed, producing free fatty acids; and (2) unconjugated unsaturated fatty acids with two or more appropriate double bonds are conjugated.
  • Commercial CLA oils available at the present time typically made from sunflower oil, are sold without further purification. They contain a mixture of CLA isomers as well as other saturated and unsaturated fatty acids. Generally, chemical synthesis produces about 20-35% (cis,trans)-9, 11-CLA and about 20-35 % (trans,cis)-10, 12-CLA, and the balance as a variety of other isomers.
  • non-active, non-natural isomers introduces the need to purify (cis,trans)-9,ll-CLA and/or (trans,cis)-10,12-CLA, or to demonstrate the safety and seek regulatory approval of these non-beneficial, non- natural isomers for human use. It is not feasible economically, however, to isolate single isomers of CLA from the CLA made by alkaline isomerization. Using a fractional crystallization procedure, it is possible to enrich 9, 11-CLA relative to 10, 12- CLA and vice versa. Another approach, described in WO 97/18320 to Loders Croklaan B.V. uses lipases to selectively esterify 10,12-CLA and thus enrich the 9,11- CLA fraction. None of the above-described methods, however, allow for the production of high purity, single isomer CLA.
  • One method of overcoming the shortcomings of chemical transformation is a whole cell transformation or an enzymatic transformation of linoleic acid, linolenic acid or their derivatives to CLA. It is well known that a biological system can be an effective alternative to chemical synthesis in producing a desired chemical compound where such a biological system is available.
  • the existence of linoleate isomerase enzyme to convert linoleic acid to CLA has been known for over thirty years, however, no one has yet successfully isolated the enzyme. And because it has not yet been isolated, the linoleate isomerase enzyme has not been sequenced.
  • the linoleate isomerase enzyme converts linoleic acid to CLA as an intermediate in the biohydrogenation step.
  • Kepler and Tove have identified this enzyme in Butyrivibriofibrisolvens.
  • Kepler and Tove J. Biol. Chem. , 1966, 241, 1350.
  • they could not solubilize the activity, i.e. , they were unable to isolate the enzyme in any significantly pure form.
  • Kepler and Tove J. Biol.
  • the present invention generally relates to isolated linoleate isomerase nucleic acid molecules, isolated linoleate isomerase proteins, immobilized bacterial cells having a genetic modification that increases the action of linoleate isomerase, and methods of using such nucleic acid molecules, proteins and cells to produce CLA.
  • One embodiment of the invention relates to an isolated linoleate isomerase. Included in the invention are linoleate isomerases from Lactobacillus, Clostridium, Propior ⁇ bacteriwn, Butyrivibrio and Eubacterium, and particularly, from Lactobacillus reuteri, Clostridium sporogenes, Propionibacterium acnes, Butyrivibrio fibrisolvens, Propionibacterium a ⁇ dipropiom ⁇ , Propionibacterium freudenreichii and Eubacterium lent m.
  • linoleate isomerases include linoleate isomerases from Lactobacillus reuteri, Clostridium sporogenes, and Propionibacterium acnes.
  • an isolated linoleate isomerase of the present invention converts linoleic acid and linolenic acid to CLA, including (cis, trans)-9, 11 -linoleic acid and/or (trans, cw)-10,12-linoleic acid.
  • a linoleate isomerase of the present invention includes linoleate isomerases having one or more of the following biochemical characteristics: a size of about 50 kDa or about 67 kDa; an optimum pH of about 6.8 or about 7.5 ; a specific linoleic acid isomerization activity of at least about 1000 nmoles mg "1 min "1 ; a Km of about 8.1 M for linoleic acid, a pH optimum of about 7.5, and a Ki of about 80 M for oleic acid; and/or an initial velocity that decreases at about 60 ⁇ M linoleic acid.
  • a linoleate isomerase of the present invention can be either a membrane bound or a soluble enzyme.
  • the linoleate isomerase of the present invention can include lipid material.
  • an isolated linoleate isomerase of the present invention includes an amino acid sequence encoded by a nucleic acid molecule that hybridizes under stringent hybridization conditions to a nucleic acid molecule comprising the complement of a sequence selected from the group of SEQ ID NO:4, SEQ ID NO:8, SEQ ID NO: 10, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17 and SEQ ID NO:26.
  • the isolated linoleate isomerase is encoded by a nucleic acid molecule which includes a nucleic acid sequence having at least 24 contiguous nucleotides having 100% identity with nucleic acid sequence SEQ ID NO: 17.
  • an isolated linoleate isomerase of the present invention includes an amino acid sequence with at least about 70% identity with an amino acid sequence selected from the group of SEQ ID NO: 1, SEQ ID NO:5, SEQ ID NO:9, SEQ ID NO: 11 and SEQ ID NO: 18.
  • an isolated linoleate isomerase is encoded by a nucleic acid molecule comprising a nucleic acid sequence selected from the group of SEQ ID NO:4, SEQ ID NO:8, SEQ ID NO: 10, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16,
  • Isolated linoleate isomerases of the present invention include proteins having an amino acid sequence selected from the group of SEQ ID NO:l, SEQ ID NO:5, SEQ ID NO:9, SEQ ID NO: 11, SEQ ID NO: 18, with SEQ ID NO: 18 being most preferred. Also included in the present invention are homologues of linoleate isomerase proteins, including proteins having an amino acid sequence having at least 8 contiguous amino acids with 100% identity to SEQ ID NO: 18, and proteins encoded by naturally occurring allelic variants of linoleate isomerase nucleic acid molecules.
  • the linoleate isomerase is bound to a solid support, which includes, but is not limited to organic supports, biopolymer supports and inorganic supports.
  • a solid support which includes, but is not limited to organic supports, biopolymer supports and inorganic supports.
  • Another embodiment of the present invention relates to an isolated antibody that selectively binds to the isolated linoleate isomerase of the present invention.
  • Yet another embodiment of the present invention relates to a method for producing CLA, including contacting an oil, which comprises a compound selected from the group of linoleic acid and linolenic acid, with an isolated linoleate isomerase enzyme of the present invention to convert at least a portion of the compound to CLA.
  • the compound is in the form of a triglyceride and the method further includes contacting the oil with a hydrolysis enzyme to convert at least a portion of the triglyceride to free fatty acids.
  • a hydrolysis enzyme can include lipases, phospholipases and esterases.
  • the method of the present invention can also include a step of recovering the CLA.
  • the CLA can included (cis, trans)-9, 11 -linoleic acid and/or (trans, cw)-10,12-linoleic acid.
  • the oil can include, but is not limited to, sunflower oil, safflower oil, corn oil, linseed oil, palm oil, rapeseed oil, sardine oil, herring oil, mustard seed oil, peanut oil, sesame oil, perilla oil, cottonseed oil, soybean oil, dehydrated castor oil and walnut oil.
  • the linoleate isomerase enzyme is bound to a solid support, which can include organic supports, biopolymer supports and inorganic supports.
  • nucleic acid molecule selected from the group of: (a) a nucleic acid molecule comprising a nucleic acid sequence that encodes a protein having an amino acid sequence selected from the group of SEQ ID NO:l, SEQ ID NO:5, SEQ ID NO:9, SEQ ID NO: ll, and SEQ ID NO: 18; (b) a nucleic acid molecule encoding a homologue of any of such amino acid sequences of (a), wherein the homologue comprises at least 8 contiguous amino acids having 100% identity with amino acids in such amino acid sequences; (c) a nucleic acid molecule comprising a naturally occurring allelic variant of a nucleic acid molecule encoding any of such amino acid sequences of (a); and, (d) a nucleic acid molecule that is complementary to any of the nucleic acid molecules of (a), (b) or (c).
  • an isolated nucleic acid molecule of the present invention encodes a linoleate isomerase, including a linoleate isomerase homologue.
  • such an isolated nucleic acid molecule hybridizes under stringent conditions to a nucleic acid molecule having a nucleic acid sequence selected from the group of SEQ ID NO:4, SEQ ID NO:8, SEQ ID NO: 10, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17, SEQ ID NO:26, and/or the complement of any of such nucleic acid sequences.
  • an isolated nucleic acid molecule of the present invention includes a nucleic acid sequence having at least about 70% identity with a nucleic acid sequence selected from the group of SEQ ID NO:4, SEQ ID NO: 8, SEQ
  • an isolated nucleic acid molecule of the present invention includes a nucleic acid sequence having at least 24 contiguous nucleotides having 100% identity with nucleic acid sequence SEQ ID NO: 17.
  • Preferred nucleic acid molecules of the present invention include molecules that hybridize under stringent hybridization conditions with a nucleic acid molecule selected from the group of nCLA g7 , nCLA 596 , nCLA 1709 , nCLA 3SS1> nCLA 1776 and nCLA 7n3 .
  • an isolated nucleic acid molecule of the present invention has a sequence selected from the group of SEQ ID NO:4, SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17 and SEQ ID NO:
  • An isolated nucleic acid molecule of the present invention preferably encodes a linoleate isomerase protein of the present invention as described above.
  • the isolate nucleic acid molecule of the present invention includes linoleate isomerase nucleic acid molecules from microorganisms including, but not limited to,
  • Lactobacillus, Clostridium, Propionibacterium, Butyrivibrio, and Eubacterium with Lactobacillus reuteri, Clostridium sporogenes, Propionibacterium acnes, Butyrivibrio fibrisolvens, Propionibacterium acidipropionici, Propionibacterium freudenreichii and Eubacterium lentum being particularly preferred.
  • Most preferred linoleate isomerase nucleic acid molecules are from Lactobacillus reuteri, Clostridium sporogenes, or
  • recombinant molecules recombinant viruses and recombinant cells which include an isolated nucleic acid molecule of the present invention.
  • recombinant cell of the present invention is from a microorganism which includes, but is not limited to, Lactobacillus reuteri,
  • Yet another embodiment of the present invention relates to a method to produce linoleate isomerase, comprising culturing a recombinant cell transformed with an isolated nucleic acid molecule encoding linoleate isomerase.
  • Another embodiment of the present invention relates to a method for producing CLA, including contacting an oil which comprises a compound selected from the group of linoleic acid and linolenic acid, with an isolated linoleate isomerase enzyme encoded by the isolated nucleic acid molecule of the present invention to convert at least a portion of the compound to CLA.
  • the cell can be a microorganism which includes, but is not limited to Lactobacillus, Clostridium, Propionibacterium, Butyrivibrio, Escherichia, Bacillus or
  • the genetic modification results in overexpression of linoleate isomerase by the bacterial cell.
  • the genetic modification can result in at least one amino acid modification selected from the group consisting of deletion, insertion, inversion, substitution and derivatization of at least one amino acid residue of the linoleate isomerase, wherein such modification results in increased linoleate isomerase action, reduced substrate inhibition, and/or reduced product inhibition.
  • the genetic modification includes transformation of the cell with a recombinant nucleic acid molecule encoding a linoleate isomerase of the present invention, wherein the recombinant nucleic acid molecule is operatively linked to a transcription control sequence.
  • the recombinant nucleic acid molecule can include any of the isolated nucleic acid molecules described above, including a nucleic acid sequence encoding a homologue of linoleate isomerase. In one embodiment, such a homologue has an amino acid sequence having at least 8 contiguous amino acids with 100% identity to amino acid sequence SEQ ID NO: 18. In one embodiment, the recombinant nucleic acid molecule is integrated into the genome of the bacterial cell. In another embodiment, the recombinant nucleic acid molecule encoding linoleate isomerase comprises a genetic modification which increases the action of the linoleate isomerase and in another embodiment, the genetic modification reduces substrate and/or product inhibition of the linoleate isomerase. In another embodiment, an immobilized bacterial cell of the present invention can be lysed. The cell can be immobilized by crosslinking with a bifunctional or multifunctional crosslinking agent, including, but not limited to glutaraldehyde.
  • Yet another embodiment of the present invention relates to a method for producing CLA, including contacting an oil which includes a compound selected from the group of linoleic acid and linolenic acid, with an immobilized bacterial cell having a linoleate isomerase, to convert at least a portion of the compound to CLA.
  • the bacterial cell can be from a microorganism including Lactobacillus, Clostridium, Propionibacterium, Butyrivibrio, Escherichia, Bacillus and Eubacterium cells, preferably Lactobacillus reuteri, Clostridium sporogenes, Propionibacterium acnes, Propionibacterium freudenreichii, Propionibacterium acidipropionici, Escherichia coli,
  • the cell can be a naturally occurring bacterial cell having a linoleate isomerase, or a genetically modified microorganism as described above.
  • a genetically modified microorganism has increased linoleate isomerase action.
  • the compound can include compounds in the form of a triglyceride such that at least a portion of the triglycerides are converted to free fatty acids. Other features of the method are as described above in the method to produce CLA.
  • FIG. IA is a line graph showing whole cell biotransformation of CLA from linoleic acid by Clostridium sporogenes ATCC 25762 under aerobic conditions.
  • Fig. IB is a line graph showing whole cell biotransformation of CLA from linoleic acid by Clostridium sporogenes ATCC 25762 under anaerobic conditions.
  • Fig. 2A is a line graph illustrating whole cell biotransformation of CLA from linoleic acid by C. bifermentans ATCC 638 under aerobic conditions.
  • Fig. 2B is a line graph illustrating whole cell biotransformation of CLA from linoleic acid by C. bifermentans ATCC 638 under anaerobic conditions.
  • Fig. 3 A is a line graph showing whole cell biotransformation of CLA from linoleic acid by Propionibacterium jensenii ATCC 14073.
  • Fig. 3B is a line graph showing whole cell biotransformation of CLA from linoleic acid by P. acnes ATCC 6919.
  • Fig. 4 is a line graph demonstrating whole cell biotransformation of CLA from linoleic acid by P. acidipropionici ATCC 25562.
  • Fig. 5 is a line graph illustrating whole cell biotransformation of CLA from linoleic acid by L. reuteri PYR8.
  • Fig. 6 is a line graph showing DEAE chromatography of detergent solubilized isomerase by L. reuteri PYR8.
  • Fig. 7 is a line graph demonstrating hydroxyapatite chromatography of isomerase activity by L. reuteri PYR8.
  • Fig. 8 is a line graph illustrating chromatofocusing of linoleic acid isomerase activity by L. reuteri PYR8.
  • Fig. 9 is a schematic illustration of the linoleate isomerase genes and flanking open reading frames in L. reuteri PYR8.
  • Fig. 10 is a schematic illustration of the putative transcription terminator in the linoleate isomerase gene.
  • Fig. 11 is an illustration of several constructs for linoleate isomerase expression in is. coli.
  • Fig. 12 is an illustration of several constructs for linoleate isomerase expression in Bacillus.
  • Fig. 13 is a flow diagram of the experimental protocol for the preparation of different protein fractions of E. coli which have expressed recombinant linoleate isomerase.
  • Fig. 14 is a line graph showing the formation of rlO,cl2-CLA from linoleic acid using whole cells of P. acnes.
  • Fig. 15 is a flow diagram showing the cell fractionation protocol for P. acnes
  • Fig. 16 is a line graph showing the effect of pH on linoleate isomerase activity in crude extracts of P. acnes ATCC 6919.
  • Fig. 17 is a line graph showing the time course of CLA formation in crude extracts of P. acnes ATCC 6919.
  • Fig. 18 is a line graph showing the time course for the formation of CLA in crude extracts of P. acnes ATCC 6919 at different levels of linoleic acid.
  • Fig. 19. is a line graph showing end point for formation of CLA in crude extracts of P. acnes ATCC 6919 at different levels of linoleic acid.
  • Fig. 20 is a graph illustrating DEAE ion exchange chromatography of total soluble protein from P. acnes ATCC 6919.
  • Fig. 21 is a graph illustrating hydrophobic interaction chromatography of total soluble protein from P. acnes ATCC 6919.
  • Fig. 22 is a graph illustrating chromatofocusing of isomerase activity from P. acnes ATCC 6919.
  • Fig. 23A is a graph showing a time course of CLA formation by C. sporogenes
  • Fig. 23B is a graph showing a time course of CLA formation by C. sporogenes ATCC 25762 under anaerobic conditions at room temperature.
  • Fig. 23C is a graph showing a time course of CLA formation by C. sporogenes ATCC 25762 under aerobic conditions at 37°C.
  • Fig. 23D is a graph showing a time course of CLA formation by C. sporogenes ATCC 25762 under anaerobic conditions at 37°C.
  • Fig. 24 is a flow diagram showing an extraction protocol for C. sporogenes ATCC 25762.
  • Fig. 25 is a line graph showing linoleate isomerase optimum pH and temperature in C. sporogenes ATCC 25762.
  • Fig. 26 is a line graph showing optimum linoleic acid concentration for C. sporogenes ATCC 25762 linoleate isomerase.
  • Fig. 27 is a graph showing the time course for CLA formation by C. sporogenes ATCC 25762 linoleate isomerase.
  • Fig. 28 is a bar graph illustrating the stability of C. sporogenes ATCC 25762 linoleate isomerase in Tris and phosphate buffers.
  • Fig. 29 is an elution profile of fresh C. sporogenes ATCC 25762 linoleate isomerase extracts from DEAE-5PW.
  • Fig. 30 is a bar graph demonstrating the effect of culture medium on C. sporogenes ATCC 25762 growth and linoleate isomerase activity.
  • Fig. 31 is a bar graph showing the effect of CaCl 2 on C. sporogenes ATCC 25762 linoleate isomerase activity.
  • Fig. 32 is a bar graph showing the effect of chelating agents on C. sporogenes ATCC 25762.
  • Fig. 33 is a bar graph showing the effect of chelating agents on stability of linoleate isomerase.
  • Fig. 34 is a line graph illustrating the effect of pH on extraction efficiency of linoleate isomerase in C. sporogenes ATCC 25762.
  • Fig. 35 is a line graph demonstrating the half lives of linoleate isomerase in C. sporogenes ATCC 25762 versus pH.
  • Fig. 36 is a bar graph showing the effect of buffer system on the activity of linoleate isomerase in C. sporogenes ATCC 25762.
  • Fig. 37 is a line graph illustrating the effect of glycerol and salt concentration on the stability of crude extracts of linoleate isomerase in C. sporogenes ATCC 25762.
  • Fig. 38 is a line graph showing the stability of detergent solubilized linoleate isomerase in C. sporogenes ATCC 25762.
  • Fig. 39 is an elution profile of C. sporogenes ATCC 25762 linoleate isomerase on DEAE Mono Q.
  • Fig. 40 is an elution profile of C. sporogenes ATCC 25762 detergent solubilized linoleate isomerase on DEAE-5PW column.
  • Fig. 41 is an elution profile showing separation of partially purified C. sporogenes ATCC 25762 linoleate isomerase by chromatofocusing.
  • the isolated linoleate isomerase can be used to produce CLA from linoleic acid, linolenic acid or their derivatives. More specifically, isolated linoleate isomerase can convert linoleic acid to conjugated linoleic acid and/or linolenic acid to conjugated linolenic acid.
  • conjugated refers to a molecule which has two or more double bonds which alternate with single bonds in an unsaturated compound.
  • Linoleate isomerase is a part of a biohydrogenation pathway in microorganisms which convert linoleic acid and other unsaturated fatty acids containing a 9,12-diene moiety into a 9, 11 -conjugate diene moiety which is then further metabolized to other fatty acids containing a 9-11 monoene moiety.
  • most linoleate isomerase converts (cis,cis)-9,12-linoleic acid to (cis,trans)-9,ll-linoleic acid as an intermediate in the biohydrogenation pathway.
  • the formation of CLA is followed by metabolism to other CLA isomers as well as metabolism to non-CLA compounds, such as a monoene fatty acid. Lactobacillus reuteri, however, produces and accumulates
  • CLA as an end product.
  • Other microorganisms such as Propionibacterium acnes convert (cis,cis)-9,12-linoleic acid to (trans,cis)-10,12-linoleic acid.
  • isolated linoleate isomerase refers to a linoleate isomerase outside of its natural environment in a pure enough form to achieve a significant increase in activity over crude extracts having linoleate isomerase activity.
  • a linoleate isomerase can include, but is not limited to, purified linoleate isomerase, recombinantly produced linoleate isomerase, membrane bound linoleate isomerase, linoleate isomerase complexed with lipids, linoleate isomerase having an artificial membrane, soluble linoleate isomerase and isolated linoleate isomerase containing other proteins.
  • An “artificial membrane” refers to any membrane-like structure that is not part of the natural membrane which contain linoleate isomerase.
  • An isolated linoleate isomerase of the present invention can be characterized by its specific activity.
  • a "specific activity” refers to the rate of conversion of linoleic acid to CLA by the enzyme. More specifically, it refers to the number of molecules of linoleic acid converted to CLA per mg of the enzyme per time unit.
  • the isolated linoleate isomerase of the present invention has a specific activity of at least about 1000 nmoles mg "1 min "1 , more preferably at least about 10,000 nmoles mg "x min "1 , and most preferably at least about 100,000 nmoles mg "1 min "1 .
  • Menten constant (IC- . K,- is a kinetic (i.e. , rate) constant of the enzyme-linoleic acid complex under conditions of the steady state.
  • the isolated linoleate isomerase of the present invention has K-, of at least about 8.1 ⁇ M at a pH of about 7.5 and at a temperature of about 20° C.
  • Kj is a dissociation rate of the oleic acid- enzyme complex.
  • the isolated linoleate isomerase of the present invention has Kj of from about 50 ⁇ M to about 100 ⁇ M at a pH of about 7.5 and at a temperature of about 20°C, and more preferably, greater than 100 ⁇ M, with no inhibition being most preferred.
  • the initial velocity (v 0 ) refers to the initial conversion rate of linoleic acid to CLA by the enzyme. Specifically, it refers to the number of molecules of linoleic acid converted to CLA per mg of the enzyme per time unit.
  • the maximum initial velocity rate of the isolated linoleate isomerase at a pH of about 7.5 is least about 100 nmoles/(sec-mg of protein), more preferably at least about 1,000 nmoles/(sec-mg of protein), and most preferably at least about 10,000 nmoles/(sec-mg of protein).
  • the isolated linoleate isomerase can be further characterized by its optimum pH.
  • the optimum pH refers to the pH at which the linoleate isomerase has a maximum initial velocity.
  • the optimum pH is between about 5 and about 10, more preferably between about 6 and about 8, and most preferably from about 6.8 to about 7.5.
  • Further embodiments of the isolated linoleate isomerase of the present invention include proteins which are encoded by any of the nucleic acid molecules which are described below. Further embodiments of the present invention include nucleic acid molecules that encode linoleate isomerases.
  • nucleic acid molecules include isolated nucleic acid molecules that hybridize under stringent hybridization conditions with: the complement of a gene encoding a naturally occurring linoleate isomerase, a nucleic acid molecule comprising the complement of a nucleic acid molecule encoding an amino acid sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO:5, SEQ ID NO:9, SEQ ID NO: 11 and/or SEQ ID NO: 18, or a nucleic acid molecule comprising the complement of a nucleic acid molecule having a nucleic acid sequence SEQ ID NO:4, SEQ ID NO:8, SEQ ID NO: 10, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17 or SEQ ED NO:26.
  • the present invention includes an isolated nucleic acid molecule that encodes a protein comprising amino acid sequence selected from the group consisting of SEQ ID NO: l, SEQ ID NO:5, SEQ ID NO:9, SEQ ID NO: 11 and/or SEQ ID NO: 18 and an isolated nucleic acid molecule having a nucleic acid sequence of SEQ ID NO:4, SEQ ID NO:8, SEQ ID NO: 10, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17 or SEQ ID NO:26.
  • a linoleate isomerase gene i.e.
  • nucleic acid molecule which encodes a linoleate isomerase can include an isolated natural linoleate isomerase gene or a homologue thereof, the latter of which is described in more detail below.
  • a nucleic acid molecule of the present invention can include one or more regulatory regions that control production of the linoleate isomerase protein encoded by that gene (such as, but not limited to, transcription, translation or post- translation control regions) as well as a full-length or partial coding region itself. It is to be noted that an isolated linoleate isomerase nucleic acid molecule of the present invention need not encode a protein having linoleate isomerase activity.
  • a linoleate isomerase nucleic acid molecule can encode a truncated, mutated or inactive protein, for example.
  • Such genes and the proteins encoded by such genes are useful in diagnostic assays, for example, or for other purposes such as antibody production, as is described in the Examples below.
  • stringent hybridization conditions refer to standard hybridization conditions under which nucleic acid molecules are used to identify similar nucleic acid molecules. Such standard conditions are disclosed, for example, in
  • stringent hybridization and washing conditions refer to conditions which permit isolation of nucleic acid molecules having at least about 70% nucleic acid sequence identity with the nucleic acid molecule being used to probe in the hybridization reaction, more particularly at least about 75 % , and most particularly at least about 80% .
  • Such conditions will vary, depending on whether DNA:RNA or DNA:DNA hybrids are being formed. Calculated melting temperatures for DNA:DNA hybrids are 10°C less than for DNA:RNA hybrids.
  • stringent hybridization conditions for DNA:DNA hybrids include hybridization at an ionic strength of 6X SSC (0.9 M Na + ) at a temperature of between about 20°C and about 35°C, more preferably, between about 28°C and about 40°C, and even more preferably, between about 35 °C and about 45 °C.
  • stringent hybridization conditions for DNA:RNA hybrids include hybridization at an ionic strength of 6X SSC (0.9 M Na + ) at a temperature of between about 30°C and about 45°C, more preferably, between about 38°C and about 50°C, and even more preferably, between about 45°C and about 55°C.
  • T m can be calculated empirically as set forth in Sambrook et al., supra, pages 9.31 TO 9.62.
  • Preferred linoleate isomerase nucleic acid molecules of the present invention include nucleic acid molecules which comprise a nucleic acid sequence having at least about 70%, more preferably, at least about 80% and most preferably, at least about 90% identity with a nucleic acid sequence selected from SEQ ID NO:4, SEQ ID NO:8, SEQ ID NO: 10, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17 and/or SEQ ID NO:26.
  • Preferred linoleate isomerase nucleic acid molecules of the present invention also include nucleic acid molecules which comprise a nucleic acid sequence selected from SEQ ID NO:4, SEQ ID NO:8, SEQ ID NO: 10, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17 and/or SEQ ID NO:26.
  • Preferred linoleate isomerase nucleic acid molecules of the present invention also include nucleic acid molecules which comprise a nucleic acid molecule selected from nCLA ⁇ , nCLA ⁇ , nCLA 09 , nCLA , nCLA 23 , nCLA 3j5 ⁇ , nCLA 1776 and/or nCLA 7n3 .
  • the statistical significance threshold for reporting matches against database sequences is 10, such that 10 matches are expected to be found merely by chance, according to the stochastic model of Karlin and Altschul (1990). If the statistical significance ascribed to a match is greater than the E ⁇ XPECT threshold, the match will not be reported. Lower EXPECT thresholds are more stringent, leading to fewer chance matches being reported. Fractional values are acceptable. (See parameter E in the BLAST Manual).
  • Cutoff score for reporting high-scoring segment pairs The default value is calculated from the EXPECT value (see above). HSPs are reported for a database sequence only if the statistical significance ascribed to them is at least as high as would be ascribed to a lone HSP having a score equal to the CUTOFF value. Higher CUTOFF values are more stringent, leading to fewer chance matches being reported. (See parameter S in the BLAST Manual). Typically, significance thresholds can be more intuitively managed using E ⁇ XPECT.
  • Low complexity sequence found by a filter program is substituted using the letter “N” in nucleotide sequence (e.g., "NNNNNNNNNNNNNNN”) and the letter "X” in protein sequences (e.g., "XXXXXXXX”). Users may turn off filtering by using the "Filter” option on the "Advanced options for the BLAST server” page. Filtering is only applied to the query sequence (or its translation products) , not to database sequences. Default filtering is DUST for BLASTN, SEG for other programs.
  • NCBI gi identifiers causes NCBI gi identifiers to be shown in the output, in addition to the accession and/or locus name.
  • an isolated nucleic acid molecule is a nucleic acid molecule that has been removed from its natural milieu (i.e., that has been subject to human mampulation) and can include DNA, RNA, or derivatives of either DNA or RNA. As such, "isolated” does not reflect the extent to which the nucleic acid molecule has been purified.
  • An isolated linoleate isomerase nucleic acid molecule of the present invention can be isolated from its natural source or produced using recombinant DNA technology (e.g., polymerase chain reaction (PCR) amplification, cloning) or chemical synthesis.
  • PCR polymerase chain reaction
  • Isolated linoleate isomerase nucleic acid molecules can include, for example, natural allelic variants and nucleic acid molecules modified by nucleotide insertions, deletions, substitutions, and/or inversions in a manner such that the modifications do not substantially interfere with the nucleic acid molecule's ability to encode a linoleate isomerase of the present invention or to form stable hybrids under stringent conditions with natural gene isolates (i.e., a linoleate isomerase nucleic acid homologue).
  • An isolated linoleate isomerase nucleic acid molecule can include degeneracies.
  • nucleotide degeneracies refers to the phenomenon that one amino acid can be encoded by different nucleotide codons.
  • nucleic acid sequence of a nucleic acid molecule that encodes a linoleate isomerase of the present invention can vary due to degeneracies.
  • a linoleate isomerase nucleic acid molecule homologue can be produced using a number of methods known to those skilled in the art (see, for example, Sambrook et al.).
  • nucleic acid molecules can be modified using a variety of techniques including, but not limited to, by classic mutagenesis and recombinant DNA techniques (e.g., site-directed mutagenesis, chemical treatment, restriction enzyme cleavage, ligation of nucleic acid fragments and/or PCR amplification), or synthesis of oligonucleotide mixtures and ligation of mixture groups to "build" a mixture of nucleic acid molecules and combinations thereof.
  • Nucleic acid molecule homologues can be selected by hybridization with a linoleate isomerase gene or by screening the function of a protein encoded by a nucleic acid molecule (e.g., ability to convert linoleic acid to CLA).
  • nucleic acid molecule homologues of the present invention can include nucleic acid sequences comprising at least 24 contiguous nucleotides having 100% identity with nucleic acid sequence SEQ ID NO: 17, and more preferably, at least about 30, and even more preferably, at least about 42 contiguous mucleotides having 100% identity with nucleic acid sequence SEQ ID NO: 17.
  • nucleic acid molecule homologues encode proteins having an amino acid sequence comprising at least 8, and preferably 10, and even more preferably 14 contiguous amino acid residues having 100% identity with amino acid sequence SEQ ID NO: 18. According to the present invention, the term "contiguous" means to be connected in an unbroken sequence.
  • One embodiment of the present invention includes a recombinant vector, which includes at least one isolated nucleic acid molecule of the present invention, inserted into any vector capable of delivering the nucleic acid molecule into a host cell to form a recombinant cell.
  • a vector contains heterologous nucleic acid sequences, that is nucleic acid sequences that are not naturally found adjacent to nucleic acid molecules of the present invention.
  • the vector can be either RNA or DNA, either prokaryotic or eukaryotic, and typically is a virus or a plasmid.
  • Recombinant vectors can be used in the cloning, sequencing, and/or otherwise manipulating of linoleate isomerase nucleic acid molecules of the present invention.
  • the vector can be expressed as an extrachromosomal element (e.g., a plasmid) or it can be integrated into the chromosome. The entire vector can remain in place, or under certain conditions, the plasmid DNA can be deleted leaving behind the nucleic acid molecule of the present invention.
  • the integrated nucleic acid molecule can be under chromosomal promoter control, under native or plasmid promoter control, or under a combination of several promoter controls. Single or multiple copies of the nucleic acid molecule can be integrated into the chromosome.
  • a recombinant molecule includes a nucleic acid molecule of the present invention operatively linked to one or more transcription control sequences to form a recombinant molecule.
  • the phrase "recombinant molecule” primarily refers to a nucleic acid molecule or nucleic acid sequence operatively linked to a transcription control sequence, but can be used interchangeably with the phrase "nucleic acid molecule”.
  • the phrase "operatively linked” refers to linking a nucleic acid molecule to a transcription control sequence in a manner such that the molecule is able to be expressed when transfected (i.e.
  • Transcription control sequences are sequences which control the imtiation, elongation, and termination of transcription. Particularly important transcription control sequences are those which control transcription initiation, such as promoter, enhancer, operator and represser sequences. Suitable transcription control sequences include any transcription control sequence that can function in at least one of the recombinant cells useful for expressing a linoleate isomerase of the present invention. A variety of such transcription control sequences are known to those skilled in the art. Preferred transcription control sequences include those which fimction in bacterial, fungal (e.g., yeast), insect, plant or animal cells.
  • Recombinant molecules of the present invention which can be either DNA or RNA, can also contain additional regulatory sequences, such as translation regulatory sequences, origins of replication, and other regulatory sequences that are compatible with the recombinant cell.
  • a recombinant molecule of the present invention including those which are integrated into the host cell chromosome, also contains secretory signals (i.e., signal segment nucleic acid sequences) to enable an expressed linoleate isomerase to be secreted from the cell that produces the protein.
  • Suitable signal segments include a signal segment that is naturally associated with a linoleate isomerase of the present invention or any heterologous signal segment capable of directing the secretion of a linoleate isomerase according to the present invention.
  • a recombinant molecule of the present invention comprises a leader sequence to enable an expressed linoleate isomerase to be delivered to and inserted into the membrane of a host cell.
  • Suitable leader sequences include a leader sequence that is naturally associated with a linoleate isomerase of the present invention, or any heterologous leader sequence capable of directing the delivery and insertion of a linoleate isomerase to the membrane of a cell.
  • One or more recombinant molecules of the present invention can be used to produce an encoded product (i.e., a linoleate isomerase protein) of the present invention.
  • an encoded product is produced by expressing a nucleic acid molecule as described herein under conditions effective to produce the protein.
  • a preferred method to produce an encoded protein is by transfecting a host cell with one or more recombinant molecules to form a recombinant cell. Suitable host cells to transfect include any bacterial, fungal (e.g., yeast), insect, plant or animal cell that can be transfected. Host cells can be either untransfected cells or cells that are already transformed with at least one nucleic acid molecule.
  • Preferred host cells for use in the present invention include any microorganism cell which is suitable for expression of a linoleate isomerase of the present invention, including, but not limited to, bacterial cells of the genera Lactobacillus, Clostridium, Propionibacterium, Butyrivibrio, Eubacterium, Escherichia and Bacillus.
  • Particularly preferred host cells include bacterial cells suitable as industrial expression hosts including, but not limited to Escherichia coli and Bacillus species, and particularly including, but not limited to Escherichia coli, Bacillus subtilis and Bacillus licheniformis.
  • an isolated linoleate isomerase protein of the present invention is produced by culturing a cell that expresses the protein under conditions effective to produce the protein, and recovering the protein.
  • a preferred cell to culture is a recombinant cell of the present invention.
  • Effective culture conditions include, but are not limited to, effective media, bioreactor, temperature, pH and oxygen conditions that permit protein production.
  • An effective, medium refers to any medium in which a cell is cultured to produce a linoleate isomerase protein of the present invention.
  • Such medium typically comprises an aqueous medium having assimilable carbon, nitrogen and phosphate sources, and appropriate salts, minerals, metals and other nutrients, such as vitamins. Examples of suitable media and culture conditions are discussed in detail in the Examples section.
  • Cells of the present invention can be cultured in conventional fermentation bioreactors, shake flasks, test tubes, microtiter dishes, and petri plates. Culturing can be.carried out at a temperature, pH and oxygen content appropriate for a recombinant cell. Such culturing conditions are within the expertise of one of ordinary skill in the art. Depending on the vector and host system used for production, resultant proteins of the present invention may either remain within the recombinant cell; be secreted into the fermentation medium; be secreted into a space between two cellular membranes, such as the periplasmic space in E. coli; or be retained on the outer surface of a cell or viral membrane.
  • Proteins of the present invention can be purified using a variety of standard protein purification techniques, such as, but not limited to, affinity chromatography, ion exchange chromatography, filtration, electrophoresis, hydrophobic interaction chromatography, gel filtration chromatography, reverse phase chromatography, concanavalin A chromatography, chromatofocusing and differential solubilization. Proteins of the present invention are preferably retrieved in "substantially pure” form. As used herein, “substantially pure” refers to a purity that allows for the effective use of the protein as a biocatalyst or other reagent.
  • a recombinant virus includes a recombinant molecule of the present invention that is packaged in a viral coat and that can be expressed in a cell after delivery of the virus to the cell.
  • a number of recombinant virus particles can be used, including, but not limited to, those based on alphaviruses, baculoviruses, poxviruses, adenoviruses, herpesviruses, and retroviruses.
  • nucleic acid molecules in relation to linoleate isomerase proteins refer to isolated linoleate isomerases which can be full-length linoleate isomerase proteins, truncated linoleate isomerase proteins, fusion proteins, or any homologue of such a protein.
  • a linoleate isomerase protein homologue includes linoleate isomerase proteins in which at least one or a few, but not limited to one or a few, amino acids have been deleted (e.g.
  • a truncated version of the protein such as a peptide
  • a truncated version of the protein such as a peptide
  • inserted, inverted, substituted and/or derivatized e.g., by glycosylation, phosphorylation, acetylation, myristoylation, prenylation, palmitation, amidation and/or addition of glycosylphosphatidyl inositol.
  • a linoleate isomerase protein homologue includes proteins having an amino acid sequence comprising at least
  • a linoleate isomerase protein homologue includes proteins encoded by a nucleic acid sequence comprising at least 24, and preferably at least 30, and more preferably at least
  • a linoleate isomerase protein homologue can also be identified as a protein having at least one epitope which elicits an immune response against a protein having an amino acid sequence selected from the group of SEQ ID NO: 1 , SEQ ID NO:5, SEQ ID NO:9,
  • a linoleate isomerase protein homologue has measurable linoleate isomerase enzymatic activity.
  • a homologue of a linoleate isomerase is a protein having an amino acid sequence that is sufficiently similar to a natural linoleate isomerase amino acid sequence that a nucleic acid sequence encoding the homologue is capable of hybridizing under stringent conditions to (i.e. , with) a nucleic acid molecule encoding the natural linoleate isomerase (i.e. , to the complement of the nucleic acid strand encoding the natural linoleate isomerase amino acid sequence).
  • a nucleic acid sequence complement of nucleic acid sequence encoding linoleate isomerase of the present invention refers to the nucleic acid sequence of the nucleic acid strand that is complementary to (i.e. , can form a complete double helix with) the strand for which the nucleic acid sequence encodes linoleate isomerase. It will be appreciated that a double stranded DNA which encodes a given amino acid sequence comprises a single strand DNA and its complementary strand having a sequence that is a complement to the single strand DNA.
  • nucleic acid molecules which encode the linoleate isomerase of the present invention can be either double-stranded or single-stranded, and include those nucleic acid molecules that form stable hybrids under stringent hybridization conditions with a nucleic acid sequence that encodes the amino acid sequence selected from the group consisting of SEQ ID NO:l, SEQ ID NO:5, SEQ ID NO:9, SEQ ID NO: 11 and/or SEQ ID NO: 18, and/or with the complement of the nucleic acid that encodes amino acid sequence selected from the group consisting of SEQ ID NO:l, SEQ ID NO:5, SEQ ID NO:9, SEQ ID NO: 11 and/or SEQ ID NO: 18, and/or with the complement of the nucleic acid that encodes amino acid sequence selected from the group consisting of SEQ ID NO:l, SEQ ID NO:5, SEQ ID NO:9, SEQ ID NO: 11 and/or SEQ ID NO: 18, and/or with the complement of the nucleic acid that encodes amino acid sequence selected from the group
  • Linoleate isomerase homologues can be the result of natural allelic variation or natural mutation. Linoleate isomerase homologues of the present invention can also be produced using techniques known in the art including, but not limited to, direct modifications to the protein or modifications to the gene encoding the protein using, for example, classic or recombinant DNA techniques to effect random or targeted mutagenesis.
  • allelic variant of a nucleic acid encoding linoleate isomerase is a gene that occurs at essentially the same locus (or loci) in the genome as the gene which encodes an amino acid sequence selected from the group consisting of SEQ ID NO:l, SEQ ID NO:5, SEQ ID NO:9, SEQ ID NO: 11 and or SEQ ID NO: 18, but which, due to natural variations caused by, for example, mutation or recombination, has a similar but not identical sequence.
  • Natural allelic variants typically encode proteins having similar activity to that of the protein encoded by the gene to which they are being compared.
  • One class of allelic variants can encode the same protein but have different nucleic acid sequences due to the degeneracy of the genetic code.
  • Allelic variants can also comprise alterations in the 5' or 3' untranslated regions of the gene (e.g., in regulatory control regions). Allelic variants are well known to those skilled in the art and would be expected to be found within a given bacterial species since the genome is haploid and/or among a group of two or more bacterial species.
  • Linoleate isomerase proteins also include expression products of gene fusions (for example, used to overexpress soluble, active forms of the recombinant enzyme), of mutagenized genes (such as genes having codon modifications to enhance gene transcription and translation), and of truncated genes (such as genes having membrane binding domains removed to generate soluble forms of a membrane enzyme, or genes having signal sequences removed which are poorly tolerated in a particular recombinant host). It is noted that linoleate isomerase proteins and protein homologues of the present invention include proteins which do not have linoleate isomerase enzymatic activity. Such proteins are useful, for example, for the production of antibodies and for diagnostic assays.
  • An isolated linoleate isomerase of the present invention can be identified in a straight-forward manner by: the proteins' ability to convert linoleic acid and/or linolenic acid to CLA, such as is illustrated in the Examples; the biochemical properties of the protein as described in the Examples; by selective binding to an antibody against a linoleate isomerase; and/or by homology with other linoleate isomerase amino acid and nucleic acid sequences as disclosed in the Examples.
  • the minimal size of a protein and/or homologue of the present invention is a size sufficient to be encoded by a nucleic acid molecule capable of forming a stable hybrid with the complementary sequence of a nucleic acid molecule encoding the corresponding natural protein.
  • the size of the nucleic acid molecule encoding such a protein is dependent on nucleic acid composition and percent homology between the nucleic acid molecule and complementary sequence as well as upon hybridization conditions per se (e.g., temperature, salt concentration, and formamide concentration).
  • the minimal size of such nucleic acid molecules is typically at least about 12 to about 15 nucleotides in length if the nucleic acid molecules are GC-rich and at least about 15 to about 18 bases in length if they are AT-rich.
  • the minimal size of a nucleic acid molecule used to encode linoleate isomerase protein or homologue of the present invention is from about 12 to about 18 nucleotides in length. There is no limit, other than a practical limit, on the maximal size of such a nucleic acid molecule in that the nucleic acid molecule can include a portion of a gene, an entire gene, or multiple genes, or portions thereof.
  • the minimal size of linoleate isomerase protein or homologue of the present invention is from about 4 to about 6 amino acids in length, with preferred sizes depending on whether a full-length, multivalent (i.e., fusion protein having more than one domain each of which has a function), or functional portions of such proteins are desired.
  • Preferred linoleate isomerases of the present invention include proteins which comprise an amino acid sequence having at least about 70%, more preferably, at least about 80% and most preferably, at least about 90% identity with an amino acid sequence selected from SEQ ID NO:l, SEQ ID NO:5, SEQ ID NO:9, SEQ ID NO:ll and/or SEQ ID NO: 18.
  • Preferred linoleate isomerases of the present invention also include proteins which comprise an amino acid sequence selected from SEQ ID NO: 1 ,
  • Preferred linoleate isomerases of the present invention also include proteins which comprise a protein selected from PCLA 35 , PCLA 2g , PCLA 158 , PCLA 324 and/or PCLA 591 .
  • the present invention also includes a fusion protein that includes a linoleate isomerase-containing domain attached to one or more fusion segments.
  • Suitable fusion segments for use with the present invention include, but are not limited to, segments that can: enhance a protein's stability; provide other enzymatic activity (e.g. , lipase, phospholipase, or esterase to hydrolyze esters of 9, 12-diene fatty acids to 9, 12-fatty acids); and/or assist purification of a linoleate isomerase (e.g., by affinity chromatography).
  • a suitable fusion segment can be a domain of any size that has the desired function (e.g., imparts increased stability, solubility, action or activity; provides other enzymatic activity such as hydrolysis of esters; and/or simplifies purification of a protein). Fusion segments can be joined to amino and/or carboxyl termini of the linoleate isomerase-containing domain of the protein and can be susceptible to cleavage in order to enable straight-forward recovery of a linoleate isomerase.
  • Fusion proteins are preferably produced by culturing a recombinant cell transformed with a fusion nucleic acid molecule that encodes a protein including the fusion segment attached to either the carboxyl and/or amino terminal end of a linoleate isomerase-containing domain.
  • Linoleate isomerases can be isolated from a various microorganisms including bacteria and fungi.
  • bacteria and fungi For example, bacterial genera such as Lactobacillus, Clostridium,
  • Propionibacterium, Butyrivibrio, and Eubacterium have linoleate isomerase activity.
  • bacterial species such as Lactobacillus reuteri, Clostridium sporogenes, Propionibacterium acnes, Butyrivibrio fibrisolvens, Propionibacterium acidipropionici, Propionibacterium freudenreichii and Eubacterium lentum contain linoleate isomerase.
  • a particularly preferred linoleate isomerase is Lactobacillus reuteri linoleate isomerase.
  • linoleate isomerases are linoleate isomerases from Propionibacterium acnes and Clostridium sporogenes.
  • a microorganism is genetically modified to increase the action of linoleate isomerase, and preferably, to enhance production of linoleate isomerase, and thereby,
  • a genetically modified microorganism such as any of the preferred genera of bacteria described herein, has a genome which is modified (i.e., mutated or changed) from its normal (i.e., wild-type or naturally occurring) form such that the desired result is achieved (i.e., increase the action of linoleate isomerase).
  • Genetic modification of a microorganism can be accomplished using classical strain development and/or molecular genetic techniques. Such techniques are generally disclosed, for example, in Sambrook et al. , 1989, Molecular Cloning: A Laboratory Manual, Cold Spring Harbor Labs Press. The reference Sambrook et al. , ibid. , is incorporated by reference herein in its entirety. Additionally, techniques for genetic modification of a microorganism through recombinant technology are described in detail in the Examples section.
  • a genetically modified microorganism can include a microorganism in which nucleic acid molecules have been inserted, deleted or modified (i.e., mutated; e.g., by insertion, deletion, substitution, and/or inversion of nucleotides), in such a manner that such modifications provide the desired effect within the microorganism.
  • a genetically modified microorganism includes a microorganism that has been modified using recombinant technology.
  • genetic modifications which result in a decrease in gene expression, in the function of the gene, or in the function of the gene product i.e.
  • the protein encoded by the gene can be referred to as inactivation (complete or partial), deletion, interruption, blockage or down-regulation of a gene.
  • a genetic modification in a gene which results in a decrease in the function of the protein encoded by such gene can be the result of a complete deletion of the gene (i.e., the gene does not exist, and therefore the protein does not exist), a mutation in the gene which results in incomplete or no translation of the protein (e.g. , the protein is not expressed), or a mutation in the gene which decreases or abolishes the natural function of the protein (e.g., a protein is expressed which has decreased or no enzymatic activity or action).
  • a genetic modification of a microorganism increases or decreases the action of a linoleate isomerase.
  • Such a genetic modification includes any type of modification and specifically includes modifications made by recombinant technology and by classical mutagenesis. It should be noted that reference to increasing the action (or activity) of linoleate isomerase refers to any genetic modification in the microorganism in question which results in increased functionality of the enzyme and includes higher activity of the enzymes (e.g.
  • gene copy number can be increased, expression levels can be increased by use of a promoter that gives higher levels of expression than that of the native promoter, or a gene can be altered by genetic engineering or classical mutagenesis to increase the action of an enzyme.
  • reference to decreasing the action of an enzyme refers to any genetic modification in the microorganism in question which results in decreased functionality of the enzymes and includes decreased activity of the enzymes (e.g. , specific activity), increased inhibition or degradation of the enzymes and a reduction or elimination of expression of the enzymes.
  • the action of an enzyme of the present invention can be decreased by blocking or reducing the production of the enzyme, "knocking out" the gene encoding the enzyme, reducing enzyme activity, or inhibiting the activity of the enzyme.
  • Blocking or reducing the production of an enzyme can include placing the gene encoding the enzyme under the control of a promoter that requires the presence of an inducing compound in the growth medium.
  • Blocking or reducing the activity of an enzyme could also include using an excision technology approach similar to that described in U.S. Patent No. 4,743,546, incorporated herein by reference.
  • the gene encoding the enzyme of interest is cloned between specific genetic sequences that allow specific, controlled excision of the gene from the genome. Excision could be prompted by, for example, a shift in the cultivation temperature of the culture, as in U.S. Patent No. 4,743,546, or by some other physical or nutritional signal.
  • a genetically modified microorganism includes a microorganism which has an enhanced ability to synthesize CLA.
  • an enhanced ability to synthesize a product refers to any enhancement, or up-regulation, in a pathway related to the synthesis of the product such that the microorganism produces an increased amount of the product compared to the wild-type microorganism cultured under the same conditions.
  • enhancement of the ability of a microorganism to synthesize CLA is accomplished by amplification of the expression of the linoleate isomerase gene.
  • Amplification of the expression of linoleate isomerase can be accompUshed in a bacterial cell, for example, by introduction of a recombinant nucleic acid molecule encoding the linoleate isomerase gene, or by modifying regulatory control over a native linoleate isomerase gene.
  • a bacteria which is transformed with a recombinant nucleic acid molecule comprising a nucleic acid sequence encoding a linoleate isomerase gene.
  • Preferred recombinant nucleic acid molecules comprising such a nucleic acid sequence include recombinant nucleic acid molecules comprising a nucleic acid sequence which encodes a linoleate isomerase comprising an amino acid sequence selected from SEQ ID NO:l, SEQ ID NO:5, SEQ ID NO:9, SEQ ID NO: 11 or SEQ ID NO: 18.
  • nucleic acid molecules of the present invention include nucleic acid molecules which comprise a nucleic acid sequence selected from the group of SEQ ID NO:4, SEQ ID NO:8, SEQ ID NO: 10, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17 or SEQ
  • nucleic acid molecules represent nucleic acid molecules comprising wild-type (i.e., naturally occurring) nucleic acid sequences encoding linoleate isomerases.
  • Genetically modified nucleic acid molecules which include nucleic acid sequences encoding homologues of (i.e., modified and/or mutated) linoleate isomerases are also encompassed by the present invention and are described in detail herein.
  • a linoleate isomerase with reduced substrate and/or product inhibition can be a mutated (i.e. , genetically modified) linoleate isomerase gene, for example, and can be produced by any suitable method of genetic modification.
  • a recombinant nucleic acid molecule encoding linoleate isomerase can be modified by any method for inserting, deleting, and/or substituting nucleotides, such as by error-prone PCR.
  • the gene is amplified under conditions that lead to a high frequency of misincorporation errors by the DNA polymerase used for the amplification.
  • a high frequency of mutations are obtained in the PCR products.
  • the resulting linoleate isomerase gene mutants can then be screened for reduced substrate and/or product inhibition by testing the mutant genes for the ability to confer increased CLA production onto a test microorganism, as compared to a microorganism carrying the non-mutated recombinant linoleate isomerase nucleic acid molecule.
  • linoleate isomerase decreased substrate and/or product inhibition of linoleate isomerase will typically result in a linoleate isomerase with increased action, even when the specific activity of the enzyme is remains the same, or actually is decreased, relative to a naturally occurring linoleate isomerase enzyme. Therefore, it is an embodiment of the present invention to produce a genetically modified linoleate isomerase with increased action and increased in vivo enzymatic activity, which has unmodified or even decreased specific activity as compared to a naturally occurring linoleate isomerase. Also encompassed by the present invention are genetically modified linoleate isomerases with increased specific activity.
  • linoleate isomerase a genetically modified recombinant nucleic acid molecule comprising a nucleic acid sequence encoding a mutant, or homologue, linoleate isomerase.
  • linoleate isomerases can be referred to herein as linoleate isomerase homologues. Protein homologues are described in detail herein.
  • Preferred recombinant nucleic acid molecules comprising such a nucleic acid sequence include recombinant nucleic acid molecules comprising a nucleic acid sequence which encodes a linoleate isomerase comprising an amino acid sequence selected from the group of SEQ ID NO:l, SEQ ID NO:5, SEQ ID NO:9, SEQ ID NO: 11 or SEQ ID NO: 18.
  • Other preferred recombinant nucleic acid molecules comprise a nucleic acid sequence selected from the group of SEQ ID NO:4, SEQ ID NO:8, SEQ ID NO: 10, SEQ ID
  • nucleic acid molecules useful in the present invention include nucleic acid molecules comprising nucleic acid molecules selected from the group of nCLA g7 , nCLA 596 , nCLA 1709 , nCLAj ,, nCLA 23 , nCLA 3551 , nCLA 1776 and/or nCLA 7113 .
  • Another embodiment of the present invention is a method for producing CLA from an oil using an isolated linoleate isomerase enzyme.
  • the method can be operated in batch or continuous mode using a stirred tank, a plug-flow column reactor or other apparatus known to those skilled in the art.
  • the oil comprises a compound selected from the group consisting of free fatty acids, salts of free fatty acids (e.g. , soaps), and mixtures containing linoleic acid, linolenic acid and mixtures thereof.
  • the oil comprises at least about 50% by weight of the compound, more preferably at least about 60% by weight, and most preferably at least about 80% by weight.
  • the method of the present invention converts at least a portion of the compound to CLA.
  • at least about 50% of the oil is converted to CLA, more preferably at least about 70% , and most preferably at least about 95% .
  • the oil is selected from the group consisting of sunflower oil, safflower oil, corn oil, linseed oil, palm oil, rapeseed oil, sardine oil, herring oil, mustard seed oil, peanut oil, sesame oil, perilla oil, cottonseed oil, soybean oil, dehydrated castor oil and walnut oil.
  • the method includes contacting the oil with a hydrolysis enzyme to convert at least a portion of the triglyceride to free fatty acids.
  • Hydrolysis enzymes include any enzyme which can cleave an ester bond of a triglyceride to provide a free fatty acid.
  • hydrolysis enzyme is selected from the group consisting of lipases, phospholipases, and esterases. Use of enzymes to hydrolyze a triglyceride is well known to one skilled in the art.
  • the oil comprising a triglyceride of a fatty acid can be chemically hydrolyzed to convert at least a portion of the triglyceride to free fatty acids.
  • Chemical conversion of triglyceride to free fatty acids is well known to one skilled in the art.
  • a triglyceride can be hydrolyzed to provide a free fatty acid under a basic condition using a base such as hydroxides, carbonates and bicarbonates.
  • bases include sodium hydroxide, calcium hydroxide, potassium hydroxide, sodium carbonate, lithium hydroxide, magnesium hydroxide, calcium carbonate, sodium bicarbonate, lithium carbonate, and lithium bicarbonate.
  • triglycerides can be hydrolyzed to provide a free fatty acid under an acidic condition using an acid.
  • acids include, hydrochloric acid, sulfuric acid, phosphoric acid, and carboxylic acids such as acetic acid and formic acid.
  • the linoleate isomerase is bound to a solid support, i.e. , an immobilized enzyme.
  • a linoleate isomerase bound to a solid support includes immobilized isolated linoleate isomerases, immobilized bacterial cells which contain a linoleate isomerase enzyme, stabilized intact cells and stabilized cell/membrane homogenates. Stabilized intact cells and stabilized cell membrane homogenates include cells and homogenates from naturally occurring microorganisms expressing linoleate isomerase or from genetically modified microorganisms as disclosed elsewhere herein.
  • a solid support refers to any solid organic, biopolymer or inorganic supports that can form a bond with linoleate isomerase without significantly effecting the activity of isolated linoleate isomerase enzyme.
  • organic solid supports include polymers such as polystyrene, nylon, phenol-formaldehyde resins, acrylic copolymers (e.g., polyacrylamide), stabilized intact whole cells, and stabilized crude whole cell/membrane homogenates.
  • Exemplary biopolymer supports include cellulose, polydextrans (e.g. , Sephadex ® ), agarose, collagen and chitin.
  • Exemplary inorganic supports include glass beads (porous and nonporous), stainless steel, metal oxides (e.g. , porous ceramics such as ZrO 2 , TiO 2 , Al 2 O 3 , and NiO) and sand.
  • the solid support is selected from the group consisting of stabilized intact cells and/or crude cell homogenates. Preparation of such supports requires a minimum of handling and cost. Additionally, such supports provide excellent stability of the enzyme.
  • Stabilized intact cells and or cell/membrane homogenates can be produced, for example, by using bifunctional crosslinkers (e.g. , glutaraldehyde) to stabilize cells and cell homogenates.
  • bifunctional crosslinkers e.g. , glutaraldehyde
  • the cell wall and membranes act as immobilizing supports.
  • integral membrane proteins are in the "best" lipid membrane environment.
  • the cells are either no longer “alive” or “metabolizing", or alternatively, are “resting” (i.e., the cells maintain metabolic potential and active linoleate isomerase, but under the culture conditions are not growing); in either case, the immobilized cells or membranes serve as biocatalysts.
  • Linoleate isomerase can be bound to a solid support by a variety of methods including adsorption, cross-linking (including covalent bonding), and entrapment. Adsorption can be through van del Waal's forces, hydrogen bonding, ionic bonding, or hydrophobic binding.
  • Exemplary solid supports for adsorption immobilization include polymeric adsorbents and ion-exchange resins. Solid supports in a bead form are particularly well-suited. The particle size of an adsorption solid support can be selected such that the immobilized enzyme is retained in the reactor by a mesh filter while the substrate (e.g., the oil) is allowed to flow through the reactor at a desired rate. With porous particulate supports it is possible to control the adsorption process to allow linoleate isomerases or bacterial cells to be embedded within the cavity of the particle, thus providing protection without an unacceptable loss of activity.
  • Cross-linking of a linoleate isomerase to a solid support involves forming a chemical bond between a solid support and a linoleate isomerase. It will be appreciated that although cross-linking generally involves linking a linoleate isomerase to a solid support using an intermediary compound, it is also possible to achieve a covalent bonding between the enzyme and the solid support directly without the use of an intermediary compound. Cross-linking commonly uses a bifunctional or multifunctional reagent to activate and attach a carboxyl group, amino group, sulfur group, hydroxy group or other functional group of the enzyme to the solid support. The term "activate" refers to a chemical transformation of a functional group which allows a formation of a bond at the functional group.
  • Exemplary amino group activating reagents include water-soluble carbodiimides, glutaraldehyde, cyanogen bromide, N-hydroxysuccinimide esters, triazines, cyanuric chloride, and carbonyl diimidazole.
  • Exemplary carboxyl group activating reagents include water-soluble carbodiimides, and N-ethyl-5-phenyhsoxazohum-3-sulfonate.
  • Exemplary tyrosyl group activating reagents include diazonium compounds.
  • exemplary sulfhydryl group activating reagents include dithiobis-5,5'-(2-nitrobenzoic acid), and glutathione-2- pyridyl disulfide.
  • Systems for covalently linking an enzyme directly to a solid support include Eupergir ® , a polymethacrylate bead support available from Rohm Pharma
  • Entrapment can also be used to immobilize linoleate isomerase. Entrapment of linoleate isomerase involves formation of, inter alia, gels (using organic or biological polymers), vesicles (including microencapsulation), semipermeable membranes or other matrices.
  • Exemplary materials used for entrapment of an enzyme include collagen, gelatin, agar, cellulose triacetate, alginate, polyacrylamide, polystyrene, polyurethane, epoxy resins, carrageenan, and egg albumin. Some of the polymers, in particular cellulose triacetate, can be used to entrap the enzyme as they are spun into a fiber. Other materials such as polyacrylamide gels can be polymerized in solution to entrap the enzyme. Still other materials such as polyglycol oligomers that are functionalized with polymerizable vinyl end groups can entrap enzymes by forming a cross-linked polymer with UV light illumination in the presence of a photosensitizer.
  • CLA produced by a method of the present invention can be recovered by conventional methods.
  • CLA can be produced in a two-phase aqueous-oil system with emulsified oil (e.g., emulsified with lecithin), in a co-solvent system, or most preferably, in a two- phase aqueous oil system comprising an oil stream containing very little water (i.e, only the minimum water required for enzyme activity).
  • emulsified oil e.g., emulsified with lecithin
  • a further characteristic of linoleate isomerases of the present invention is that they are not inhibited by higher log P solvents. In fact, it has been surprisingly found that in some cases linoleate isomerases of the present invention provide higher conversion of linoleic acid to CLA when immiscible solvents are used.
  • CLA can be produced using a variety of solvent systems.
  • CLA can be produced using an aqueous system or a combination of an aqueous and an organic system.
  • a solvent system for CLA production using a linoleate isomerase comprises a solvent selected from the group consisting of water, hexane decane, hexadecane, and propylene glycol.
  • Yet another embodiment of the present invention relates to a method for producing CLA which utilizes industrial expression systems formed from the microorganisms, nucleic acid molecules, and proteins of the present invention which have been disclosed herein.
  • immobilized intact whole cells or cell/membrane homogenates formed from naturally occurring microorganisms expressing linoleate isomerase or from a genetically modified microorganism as described herein (including recombinant microorganisms), wherein the microorganism stably expresses a linoleate isomerase of the present invention will be grown in a suitable culture system (e.g., fermentors).
  • a suitable culture system e.g., fermentors
  • the stabilized cells or homogenates will serve as a biocatalyst in a biotransformation process to convert linoleic acid and/or linolenic acid to CLA, according to the parameters specified elsewhere herein.
  • the biocatalyst will be reused (i.e., recycled) several times.
  • the linoleic and/or linolenic acid-containing oil stream is added to the biocatalyst in the presence of a mimmum amount of water.
  • nucleic acid molecule denoted nCSN ⁇ which is located on the strand of nCLA 35 # ⁇ at is complementary to the nucleic acid sequence SEQ ID NO: 16, and which comprises an open reading frame having nucleic acid sequence SEQ ID NO:21.
  • SEQ ID NO:21 is positioned on the strand that is complementary to nucleotide positions 1 through 726 of SEQ ID NO: 16, with a start codon approximately 275 nucleotides up-stream from the putative start codon of a nucleic acid molecule of the present invention which encodes a linoleate isomerase.
  • the deduced amino acid sequence of SEQ ID NO:21 is represented by SEQ ID NO:22.
  • a protein comprising SEQ ID NO:22 is referred to herein as PCSN ⁇ .
  • the C-terminal portion of the protein comprising SEQ ID NO:22 is not included in SEQ ID NO:22.
  • the present inventors have shown (See Example 5) that the nucleic acid sequence of SEQ ID NO:21 is 66% identical to a competence-specific nuclease (DNA entry nuclease) from Streptococcus pneumoniae (Q03158), with the amino acid sequence SEQ ID NO:22 being 51-72% identical to the amino acid sequence for this competence-specific nuclease. Therefore, it is believed to be possible that PCSN 242 represents at least a portion of a competence-specific nuclease.
  • PCSN ⁇ is contained within a protein denoted PCSN ⁇ , which has an amino acid sequence represented herein by SEQ ED NO:34.
  • SEQ ID NO:34 is encoded by a nucleic acid molecule denoted nCSN 744 , which is represented herein by SEQ ID NO: 33.
  • the amino acid sequence SEQ ID NO: 34 is about 57% identical and about 71% similar to the amino acid sequence for the above-mentioned competence-specific nuclease (BLAST, standard parameters).
  • nBSP ⁇ nucleic acid molecule denoted nBSP ⁇ , which comprises an open reading frame located upstream from an open reading frame encoding a linoleate isomerase of the present invention, and having nucleic acid sequence SEQ ID NO:27.
  • the deduced amino acid sequence of SEQ ID NO:27 is represented by SEQ ID NO:28.
  • a protein comprising SEQ ID NO:28 is referred to herein as PBSP 3 ⁇ 2 .
  • the present inventors have shown (See Example 5) that the amino acid sequence of SEQ ID NO:28 is about 56% identical and about 74% similar (using standard BLAST parameters) to a permease from Bacillus subtilis (p54425). Therefore, it is believed to be possible that PBSP 312 represents at least a portion of a permease.
  • one embodiment of the present invention is a nucleic acid molecule, denoted nUNKl 656 , which comprises an open reading frame located about 122 nucleotides downstream from an open reading frame encoding a linoleate isomerase of the present invention.
  • the nucleic acid molecule comprises a nucleic acid sequence represented by SEQ ID NO: 19, the deduced amino acid sequence of which is represented by SEQ ID NO:20.
  • a protein having SEQ ID NO:20 is referred to herein as PUNKl 21g .
  • PUNKl 2 ⁇ 8 is contained within a larger protein, denoted PUNK1 513 having a deduced amino acid sequence represented by SEQ ID NO:36.
  • SEQ ID NO:36 is encoded by a nucleic acid molecule denoted nUNKl 1540 , the nucleic acid sequence of which is represented by SEQ ID NO:35.
  • the C-terminal sequence of PUNK1 513 is incomplete.
  • nucleic acid molecule denoted nUN- ⁇ r ⁇ , which comprises an open reading frame located upstream from an open reading frame encoding a linoleate isomerase of the present invention.
  • the nucleic acid molecule nUNO ⁇ comprises a nucleic acid sequence represented by SEQ ID NO: 29, the deduced amino acid sequence of which is represented by SEQ ID NO:30.
  • a protein having SEQ ID NO:30 is referred to herein as PUNK2 199 .
  • nucleic acid molecule denoted nUNK3g 49 , which comprises an open reading frame located upstream from an open reading frame encoding a linoleate isomerase of the present invention.
  • the nucleic acid molecule nUNI ⁇ comprises a nucleic acid sequence represented by SEQ ID NO:31, the deduced amino acid sequence of which is represented by SEQ ID NO:32.
  • a protein having SEQ ID NO:32 is referred to herein as PUNK3 2g2 .
  • This example illustrates CLA production from linoleic acid using whole cell biotransformations with a variety of microorganisms.
  • the term "whole cell biotransformation” refers to a conversion of a suitable substrate to CLA by a microorganism.
  • a variety of other microorganisms were purchased from ATCC (American Type Culture Collection) and grown on Brain Heart Infusion Broth (Difco) supplemented with 0.5% yeast extract, 0.0005% hemin, 0.001% vitamin K 0.05% cysteine, and 0.001 % resazurin. Cultures were grown in closed containers with limited head space for about 12 to about 16 hours at 37°C, harvested and washed with fresh medium. Culture stocks were maintained in 10% glycerol at about -80°C.
  • Lactobacillus reuteri PYR8 (ATCC Accession No. 55739, deposited on February 15, 1996 with the American Type Culture Collection (ATCC), 10801
  • Aerobic biotransformations were carried out in baffled 250 mL shake flasks agitated at 200 rpm on a shaker at room temperature.
  • Anaerobic biotransformations were carried out in sealed 150 mL serum bottles under a 95% nitrogen/5% carbon dioxide head space at 37° C. Media were prepared anaerobically by boiling under a N 2 /CO 2 atmosphere for 15 minutes, sealed with a crimped septum and autoclaved. MRS broth (BBL) was used with L. reuteri. Supplemented Brain Heart Infusion broth was used in anaerobic biotransformations with other microorganisms. Samples were taken at appropriate intervals and analyzed for CLA as described in Example 2. In some experiments, various detergents were added to 0.1-0.5 % final concentration.
  • About 5 mL solvent was added to about 20 mL aqueous cell suspension in a 125 mL baffled shake flask incubated at room temperature.
  • Figs. IA and IB show the results of whole cell biotransformation by Clostridium sporogenes ATCC 25762 under aerobic (Fig. IA) and anaerobic (Fig. IB) conditions. As Fig. IA shows, under aerobic conditions, C.
  • Figs. 2 A and 2B show the results of whole cell biotransformation by C. bifermentans ATCC 638 under aerobic (Fig. 2A) and anaerobic (Fig. 2B) conditions.
  • Linoleic acid is more rapidly converted to (cis,trans)-9,ll-CLA by C. bifermentans ATCC 638 under aerobic conditions (Fig. 2 A) than under anaerobic conditions (Fig. 2B).
  • the highest (cis,trans)-9,ll-CLA concentration is observed at about 1 to about 5 hours under aerobic conditions.
  • C. sordellii ATCC 9714 also converts linoleic acid to (cis,trans)-9,ll-CLA under both aerobic and anaerobic conditions (data not shown).
  • Figs. 3 A, 3B and 4 show the results of whole cell biotransformation by
  • Propionibacterium jensenii ATCC 14073 (Fig. 3A), P. acnes ATCC 6919 (Fig. 3B), and P. acidipropionici ATCC 25562 (Fig. 4), respectively.
  • P. acidipropionici converts linoleic acid to (cis,trans)-9,ll-CLA
  • P. acnes converts linoleic acid to (trans,cis)-10, 12-CLA under aerobic conditions.
  • Fig. 5 shows the results of whole cell biotransformation by Lactobacillus reuteri. Unlike other microorganisms, the concentration of (cis,trans)-9,ll-CLA formed by L. reuteri from linoleic acid does not decrease significantly with time. Addition of various nonionic detergents, such as Tween-80 or Triton X-100, does not significantly increase (cis,trans)-9, 11-CLA formation.
  • various nonionic detergents such as Tween-80 or Triton X-100
  • This example describes a procedure for fatty acid analysis to determine the amount of conversion of linoleic acid to CLA.
  • Fatty acids were extracted from about 1 mL to about 2.5 mL aqueous samples with 0.5 mL of 5 M NaCI added.
  • the samples were shaken with 5 mL of 2: 1 mixture of chloroform/methanol in a glass screw cap tube with Teflon lined cap.
  • the two phases were separated and about 1 to 2 mL of the chloroform layer was removed.
  • the organic layer was dried with NajSQ, and concentrated.
  • the concentrated fatty acids were converted to methyl esters by a modification of the procedure of Chin et al., J. Food Composition, 1992, 5: 185-192.
  • About 6 mL of 4% HCl in methanol preheated to 60° C was added to the glass tube containing the fatty acid sample.
  • the tubes were sealed with a Teflon lined cap and incubated in a tube heater at 60 °C for 20 minutes, then cooled to room temperature, and 2 mL of water and 3 mL of hexane are added. After shaking, the organic layer was separated, dried with Na 2 SO 4 , and analyzed by gas chromatography. The order of four CLA peaks was (1) (cis,trans)-9,ll-CLA, (2)
  • This Example describes the purification of linoleate isomerase from L. reuteri.
  • Detergent soluble protein fractions were prepared as follows. Frozen cells were thawed and suspended in breakage buffer on ice.
  • the standard breakage buffer for L. reuteri comprised 0.1 M Bis-Tris (Calbiochem Ultrol grade) pH 5.8 (4°C), 10 mM NaCI, 10% glycerol, 2 mM dithiothreitol.
  • Tris buffer at pH 7.5 was used in place of Bis-Tris buffer.
  • the cell suspensions were broken at 18,000 psi using a SLM Aminco French press. The extract was centrifuged at 12,000 X g for 30 minutes.
  • the supernatant was further fractionated by centrifugation at 100,000 X g for 90 minutes to yield a soluble fraction and a membrane pellet.
  • the membrane pellets were resuspended (approximately 5 mg/mL) and extracted with detergent buffer (0.1 M Bis-Tris pH 5.8, 0.25 M NaCI, 10% glycerol, 2 mM dithiothreitol, 0.3% octylthioglucopyranoside (OTGP, Calbiochem Ultrol grade)) at 4°C for 4-18 hours with gentle stirring using a magnetic flea.
  • detergent buffer 0.1 M Bis-Tris pH 5.8, 0.25 M NaCI, 10% glycerol, 2 mM dithiothreitol, 0.3% octylthioglucopyranoside (OTGP, Calbiochem Ultrol grade)
  • Detergent soluble protein fractions were dialyzed overnight against low salt buffer (0.1 M Bis-Tris pH 5.8, 10 mM NaCI, 2 mM dithiothreitol, 10% glycerol, 0.3% OTGP), and applied to a 2.1 X 15 cm DEAE-5PW column (TosoHaas) previously equilibrated with low salt buffer. The column was washed (4 mL/min) with the same buffer containing 1 M NaCI (high salt buffer). The results of this step are shown in Fig. 6. Protein concentration was monitored continuously at 280 nm. About 4 mL fractions were collected and assayed for isomerase activity. Isomerase activity in the extracts was measured at 20 ppm linoleic acid. Fractions with significant isomerase activity were combined and concentrated using an Amicon ultrafiltration cell.
  • low salt buffer 0.1 M Bis-Tris pH 5.8, 10 mM NaCI, 2 mM dithiothreitol, 10% gly
  • Detergent soluble protein fractions were applied to an affinity column.
  • the affinity column was then sequentially washed (1 mL/min) with low salt buffer (75 mL), high salt buffer (50 mL) and linoleic acid buffer (100 mL) comprising 0.1 M Bis-Tris pH 5.8, 1 M NaCI, 0.3% OTGP, 2 mM dithiothreitol, 10% glycerol, 20% 1,2- propane diol.
  • the affinity column was prepared as follows. Pharmacia EAH Sepharose 4B was washed and suspended as a slurry in deionized water. A five-fold excess of ligand
  • Detergent soluble protein fractions were purified by a chromatography using DEAE-5PW column as described in Method A. The fractions containing isomerase activity were combined, concentrated, and desalted by ultrafiltration. The resulting sample was applied to a Mono PHR 5/20 column (Pharmacia, 0.5 X 20 cm) which has been previously equilibrated with a buffer comprising 25 mM triethanolamine, 1 mM dithiothreitol, 0.3% OTGP at pH 8.3. The column was then eluted with a buffer comprising 10% Polybuffer 96 (Pharmacia), 0.3% OTGP, 1 mM dithiothreitol at pH 6.5 and 1 mL fractions were collected. As shown in Fig.
  • fractions 5-15 fractions containing isomerase activity were eluted typically between fractions 27 and 47.
  • the fractions containing isomerase activity were combined and further purified by a chromatography using Superdex-200 gel filtration column as described in Method A.
  • the fraction containing isomerase activity was eluted as a single band with a mass of about 160 kD. This same band was run on a denaturing SDS-PAGE gel and resulted in a single band of about 70 kD. This 70 kD band was excised and subjected to N-terminal amino acid sequencing using techniques known to those skilled in the art.
  • SEQ ID NO: 1 A partial N-terminal amino acid sequence of about 35 amino acids was deduced and is represented herein as SEQ ID NO: 1.
  • a protein having the sequence of SEQ ID NO: 1 is referred to herein as PCLA 35 .
  • SEQ ID NO:l represents, at best, an apparent partial N-terminal amino acid sequence.
  • This example describes the procedure for determining presence of isomerase activity of a fraction or a protein.
  • This example also describes a method for conducting a kinetic assay. Linoleic isomerase activity was assayed either via CLA quantification by gas chromatography as described in Example 2 or by spectrophotometry. The enzyme assay was carried out in 0.1 M Tris buffer pH 7.5, 10 mM NaCI, 1 mM dithiothreitol, with linoleic acid at 20 parts per million (ppm), unless otherwise noted.
  • Kinetic assays were performed directly in a 0.5 mL quartz cuvette at room temperature and were continuously monitored at 234 nm. Reactions were initiated by addition of linoleic acid from a concentrated stock prepared in 1,2-propane diol.
  • Reaction buffer was the same as above except it contained 10% 1,2-propane diol.
  • This Example shows the nucleic acid cloning and sequencing of a Lactobacillus reuteri linoleate isomerase nucleic acid molecule of the present invention. It should be noted that since amino acid sequencing and nucleic acid sequencing technologies are not entirely error-free, the sequences presented in this example and those below, at best, represent apparent sequences of a linoleate isomerase of the present invention. Two sets of fully degenerated oligonucleotide primers were synthesized, corresponding the sequences of the amino acid residues 1-7 and 23-29 of SEQ ID NO: 1.
  • the first oligonucleotide primer designated CLAO1
  • CLAO1 had the following sequence: 5'-cgt gaa ttc ATG TA(T/C) TA(T/C) (T/A)(C/G)N AA(T/C) GGN AA-3 '
  • the second oligonucleotide primer designated CLAO2
  • CLAO2 had the following sequence: 5 ' -act gga tCC NAC (T/ A/G) AT (A/G) AT NGC (A/G)TG (C/T)TT-3 '
  • PCR conditions and gel purified A single band of PCR product with the expected size (about 100 bp) was detected on 3% agarose gel.
  • the PCR product was purified and cloned at the Srf I site into the vector pPCR-Script(Amp)SK(+) (Stratagen). Potential recombinant plasmids were analyzed by restriction digestion and sequenced.
  • CLA03 corresponded to nucleotides 25- 41 of nCLA g7 (SEQ ID NO:4)
  • CLA04 nucleotides 46-67 of nCLA g7
  • Genomic DNA from Lactobacillus reuteri PYR8 was digested with the restriction enzyme Bam HI, treated with T4 DNA ligase to circularize the molecules, and the resulting molecules were used as a template in PCR reactions.
  • a PCR product of 592 nucleotides was purified and cloned at the Srf I site into the vector pPCR- Script(Amp)SK(+) (Stratagen) and sequenced.
  • a 596 bp edited version of this molecule is denoted herein as nCLA 596 (SEQ ID NO: 8).
  • nCLA 596 contains both the 5' upstream and 3' downstream sequences of a linoleate isomerase gene.
  • PCLA 15g SEQ ID NO:9
  • PCLA 1Jg A protein having the sequence of SEQ ID NO:9 is referred to herein as PCLA 1Jg .
  • nCLAjc K was labeled with ? and hybridized to a Southern blot of Lactobacillus reuteri PYR8 genomic DNA digested with different restriction enzymes.
  • the partial linoleate isomerase sequence of nCLA 596 contains one Agel site and one Eco 58 I site.
  • a PCR product of about 1.1 kb was generated using the primer set of CLA03 and CLA04 as well as a product of 2.3 kb using the primer set CLA05 and CLA06 (SEQ ID NO:12 and SEQ ID NO:13, respectively).
  • CLA05 corresponds to nucleotides 326-342 of nCLA 596
  • CLA06 corresponds to nucleotides 396-414 of nCLA 59)S .
  • nCLA 1.1 kb fragment
  • nCLA 23 the clone with the 2.3 l ⁇ fragment.
  • nCLA j96 , partial nCLAj j, and partial nCLA 23 were edited to generate a composite sequence denoted herein as nCLA 1709 (SEQ ID NO: 10).
  • SEQ ID NO: 11 A protein having the sequence of SEQ ID NO: 11 is referred to herein as PCLA 324 .
  • nCLAi T r ⁇ contains part of the isomerase coding sequence as well as 5' upstream sequence.
  • the 737 nucleotide sequence upstream from the ATG codon corresponding to the first amino acid of the purified polypeptide was compared against known sequences by using Blastx (open reading frames) and Blastn (nucleotides) searches of the BLAST network. No significant homology has been found with any entry, with the score being below 176 for Blastn and 153 for Blastx.
  • the coding sequence downstream from the ATG start codon showed a homology with 67 kD myosin-crossreactive streptococcal antigen from Streptococcus pyogenes (U09352):
  • the isomerase coding sequence shows also a homology to an ORF from Staphylococcus aureus (L19300): 62% identity at both the amino acid level and the nucleotide level.
  • nCLA 355 ⁇ contains three open reading frames (Fig.
  • SEQ ID NO: 17 encodes a linoleate isomerase of the present invention.
  • nCLA 1776 encodes an approximately 67 kD (deduced) protein of 591 amino acid residues having an amino acid sequence represented by SEQ ID NO: 18.
  • a protein having amino acid sequence SEQ ID NO: 18 is referred to herein as PCLA 591 .
  • the deduced size of PCLA 591 is consistent with the size of the purified isomerase protein determined on an SDS gel.
  • Seven nucleotides upstream from the initiation codon of this first ORF (SEQ ED NO: 17) is a sequence similar to the consensus ribosome-binding-site which has been reported in Lactobacillus.
  • upstream from this first ORF are sequences similar to -10 and -35 promoter sequences. These sequence characteristics are consistent with a conclusion that the start codon at position 1000 of nCLA 3551 is the translation start codon.
  • nCLA 3551 has, upstream from the first ORF, at 36 nucleotides upstream from the start codon at position 1000, in frame, two ATG start codons in tandem. If one of these codons is a translation start codon, then a leader peptide of about 12 amino acids may be produced which is subsequently cleaved to form a mature isomerase.
  • the complete coding sequence for the linoleate isomerase gene determined as described above was compared against known sequences by using Blastx (open reading frames) and Blastn (nucleotides) searches of the BLAST network.
  • the linoleate isomerase encoded by SEQ ID NO: 17 showed 67% identity at the nucleic acid level and 70% identity at the amino acid level with the previously-mentioned
  • Staphylococcus pyogenes (U09352) 67 kD myosin-crossreactive streptococcal antigen.
  • the Staphylococcus pyogenes (U09352) protein has 590 amino acid residues.
  • the homology between the linoleate isomerase encoded by SEQ ID NO: 17 and the above- described Streptococcus aureus (L19300) gene is slightly lower: about 60% at the nucleic acid level and about 62% at the amino acid level.
  • the second open reading frame of nCLA 355 ⁇ (Fig. 9, E) is from nucleotide positions 2896 to 3551 of SEQ ED NO: 16, and is represented by SEQ ID NO: 19.
  • a nucleic acid molecule having SEQ ID NO: 19 is referred to herein as nUNKl ⁇ which encodes a protein of about 218 amino acid residues having an amino acid sequence of SEQ ID NO:20.
  • a protein having SEQ ID NO:20 is referred to herein as PUNKl 21g .
  • the function of PUNKl 21g is unknown.
  • the sequence of nUNKl ⁇ was compared with known sequences for homology and no significant homology was identified.
  • This second reading frame is located 122 nucleotides downstream from the first open reading frame (SEQ ID NO: 17) encoding the linoleate isomerase.
  • the third open reading frame of nCLA 3J5 ⁇ (Fig. 9, D) is located on the strand of nCLA 3551 that is complementary to SEQ ID NO: 16, and is represented herein as SEQ ED NO:21.
  • SEQ ID NO:21 is positioned on the strand that is complementary to nucleotide positions 1 through 726 of SEQ ID NO: 16, with start codon 275 nucleotides up-stream from position 1000 of the putative start codon of SEQ ID NO: 17.
  • a nucleic acid molecule having SEQ ID NO:21 is referred to herein as nCSN 726 which encodes at least a portion of a protein having an amino acid sequence of SEQ ID NO:22.
  • a 242 amino acid residue protein having SEQ ID NO:22 is referred to herein as PCSN ⁇ .
  • a database search showed that the nucleic acid sequence of this third ORF (SEQ ED NO:21) is about 66% identical to a competence-specific nuclease (DNA entry nuclease) from Streptococcus pneumoniae (Q03158), with the amino acid sequence SEQ ID NO:22 being about 51-72% identical to the amino acid sequence for this competence-specific nuclease. Therefore, it is believed to be possible that the third ORF identified on the complementary strand of SEQ ID NO: 16 encodes a competence-specific nuclease.
  • the following example demonstrates the cloning of sequences flanking the isomerase gene in the L. reuteri PYR8 genome.
  • a third round of inverse PCR was carried out on the circularized genomic DNA from Lactobacillus reuteri PYR8 as described in Example 5. This third round was designed to clone more sequences flanking the isomerase gene.
  • Two oligonucleotide primers designated CLAo9 and CLAolO (SEQ ID NO:23 and SEQ ED NO:24, respectively) were designed for this round of PCR.
  • CLAo9 SEQ ID NO:23
  • CLAolO was designed to correspond to the 3' end of the nCLA 355 ⁇ sequence (nucleotides 3505-3522 of SEQ ID NO: 16).
  • L. reuteri PYR8 genomic DNA was digested with Sail, religated and amplified with oligonucleotide primers CLAo9 and CLAolO.
  • a PCR product of about 3.5-4.0 kb was cloned into pPCR-Script Amp SK(+) and sequenced. This nucleic acid molecule was denoted nS L ⁇ and is represented herein by SEQ ED NO:25.
  • nS AL 3684 was confirmed by the sequences flanking the primers CLAo9 and CLAolO.
  • the sequence nSAI_ 36g4 contains a unique Sail site, which indicates the junction point of the inverse PCR product. Therefore, the sequence was spliced at the Sail site and added to the 3' and 5' ends of the sequence of nCLA 3551 (SEQ ID NO: 16).
  • This approximately 7 kb nucleic acid molecule is denoted nCLA 7U3 and is represented herein by SEQ ID NO:26.
  • the approximately 7 kb L. reuteri PYR8 genomic DNA contains 6 open reading frames, schematically illustrated in Fig. 9.
  • There are four ORF's (A, B, C and D) located 5' upstream of the isomerase gene (ISOM) and one ORF located 3' downstream of the isomerase gene.
  • the first open reading frame of nCLA 7U3 spans from nucleotide positions 1 to 941 of SEQ ID NO:26, and is represented by SEQ ID NO:27.
  • a nucleic acid molecule having SEQ ID NO:27 is referred to herein as h-iSP ⁇ which encodes a protein of about 312 amino acid residues having an amino acid sequence of SEQ ID NO:28.
  • a protein having SEQ ID NO:28 is referred to herein as PBSP 312 .
  • a database search showed that the amino acid sequence (SEQ ID NO: 28) of the protein encoded by this first ORF A (SEQ ID NO: 27) is about 56% identical and 74% similar
  • nCLA 7113 spans from nucleotide positions 1146 to 1745 of SEQ ID NO:26, and is represented by SEQ ID NO:29.
  • a nucleic acid molecule having SEQ ID NO: 29 is referred to herein as nU C ⁇ which encodes a protein of about 199 amino acid residues having an amino acid sequence of SEQ ID NO: 30.
  • a protein having SEQ ID NO: 30 is referred to herein as PUNK2 199 .
  • the function of PUNK2 199 is unknown.
  • the sequence of nUNI ⁇ o o was compared with known sequences for homology and no significant homology was identified. The highest Blastp score using standard defaults was 51.
  • nCLA 7U3 The third open reading frame of nCLA 7U3 (Fig. 9, C) spans from nucleotide positions 1742 to 2590 of SEQ ID NO:26, and is represented by SEQ ID NO:31.
  • a nucleic acid molecule having SEQ ID NO: 31 is referred to herein as nUNK3 M9 which encodes a protein of about 282 amino acid residues having an amino acid sequence of SEQ ID NO:32.
  • a protein having SEQ ID NO:32 is referred to herein as PUNK3 2g2 .
  • nCLA 7U3 The fourth open reading frame of nCLA 7U3 (Fig. 9, D) spans from nucleotide positions 2662 to 3405 of SEQ ID NO:26, and is represented by SEQ ID NO:33.
  • a nucleic acid molecule having SEQ ID NO: 33 is referred to herein as nCSN 744 which encodes a protein having an amino acid sequence of SEQ ID NO:34.
  • a 247 amino acid residue protein having SEQ ID NO: 34 is referred to herein as PCSN ⁇ .
  • PCSN ⁇ (SEQ ID NO:22), described above in Example 5 (the third ORF identified in nCLA 3 s 51 ) is included in PCSN M7 , spanning from amino acid position 1 to 242 of SEQ ID NO:34.
  • nucleic acid sequence of nCS ⁇ spans from nucleotides 1 to 726 of SEQ ID NO:33.
  • a database search showed that the amino acid sequence SEQ ID NO:34 is about 57% identical and about 71 % similar (using standard parameters) to the amino acid sequence for the above-mentioned Streptococcus pneumoniae competence-specific nuclease.
  • the fifth open reading frame of nCLA 7113 (Fig. 9, ISOM) is a nucleic acid molecule SEQ ID NO: 17) encoding the linoleate isomerase (PCLA 591 , SEQ ID NO: 18) of the present invention, as described above in Example 5.
  • nCLA 7 ⁇ 3 spans from nucleotide positions 5574-7113 of SEQ ID NO:26, and is represented by SEQ ID NO:35.
  • a nucleic acid molecule having SEQ ED NO:35 is referred to herein as nUNKl 1540 which encodes a protein having an amino acid sequence of SEQ ID NO:36.
  • a 513 amino acid residue protein having SEQ ID NO: 36 is referred to herein as PUNK1 513 .
  • PUNKl 21g (SEQ ID NO:20), described above in Example 5 (the second ORF identified in nCLA 3551 ) is included in PUNK1 513 , spanning from amino acid position 1 to 218 of
  • nucleic acid sequence of nUNKl 6S6 spans from nucleotides 1 to 656 of SEQ ID NO: 35.
  • sequence of nUNKl 1540 was compared with known sequences for homology and no significant homology was identified. The highest Blastp score for PUNK1 513 using standard defaults was 51. The C-terminal sequence of PUNK1 513 is incomplete.
  • the isomerase gene is very likely transcribed as a monocistron. This conclusion is based on two observations. First, the ORF that is located immediately upstream from the isomerase gene (Fig. 9, D) is coded on the opposite strand. Secondly, a reverse-repeat DNA sequence was observed in the region downstream from the stop codon of the isomerase gene (Fig. 10). This 28 nucleotide structure (SEQ ID NO:
  • Linoleate isomerase from L. reuteri is a membrane protein since its activity is detected mostly in membrane fraction of cellular protein extracts and detergent is needed to solubilize the enzyme.
  • the hydrophilicity plot of the isomerase ORF shows a major hydrophobic domain close to the N-terminal sequence, from amino acid residue 27 through 42. This hydrophobic domain may function as a transmembrane segment as well as part of an uncleaved signal peptide, which plays an important role in directing the protein into the membrane.
  • the peptide contains 4 cysteine residues at amino acid positions 89, 124, 336 and 430, suggesting the native protein may have one or two internal disulfide bonds.
  • Nucleotide CLAo7 (SEQ ID NO:38), the forward primer, corresponds to the positions 3296 through 3314 of the sequence nCLA 7113 (SEQ ID NO:26) and it includes a Sail site and 3 extra bases at the 5' end (lower case): 5 ' -gcagtcgacGGAGTTAAG ACTGAATTAG-3 '
  • the nucleotide CLA08B (SEQ ID NO: 39), the reverse primer, corresponds to the positions 5577 through 5593 of the sequence nCLA 7113 (SEQ ID NO:26) and it includes a Sail site and 3 extra bases at the 5' end (lower case): 5 ' -ctagtcgacGC AGTTTCTGTC ATGAC-3 '
  • the PCR product of 2.3kb was ligated with blunt ends into pPCR- Script(Amp)SK at the Srfl site. Ligated DNA was transformed into E. coli cells. Clones with inserts in both orientations were selected and tested for expression of the isomerase gene. In the construct #1 (Fig. 11), the isomerase gene was placed downstream from the lac promoter. In the construct #2 (Fig. 11), the isomerase gene was placed reverse to the lac promoter.
  • E. coli cells transformed with the different isomerase constructs were grown to mid log phase, induced with or without IPTG for
  • the lack of catalytic activity may be a result of incorrect folding and/or membrane insertion of the isomerase in the heterologous system.
  • pET vectors were used to develop isomerase gene constructs where the isomerase coding sequence is fused to a His tag at the C-terminus. Using a commercial antibody specific to His tag, it would be possible to monitor the levels of isomerase-His tag fusion protein synthesized in E. coli, Lactobacillus, Bacillus, or any other appropriate expression host by Western blot analysis, even if the enzyme was inactive. Since the constructs would be made with E. coli plasmids, E. coli systems could be used to test the method. The isomerase-His tag protein was expressed in E.
  • isomerase protein coli to produce large amounts of isomerase protein.
  • This protein can be further purified under denaturing conditions with nickel columns and used in the production of antibodies specific to the L. reuteri PYR8 linoleate isomerase. Isomerase expression in the native host and recombinant systems can be monitored with these antibodies. Additionally, the antibodies can be used in immunoscreening to identify new microorganism strains that produce linoleate isomerases, and eventually to aid in the cloning of additional linoleate isomerase genes.
  • E. coli transformed with and expressing the PYR8 isomerase gene with a His tag were grown under standard conditions to study expression of the isomerase protein.
  • a band between 60 and 70 kD was predominant in the cell lysate. This band was present at a high level even before induction.
  • IPTG induced a very strong overproduction of the protein (data not shown).
  • the highest expression level was achieved two hours after IPTG induction. This protein band was strongly recognized by anti-His tag antibody on Western blot, confirming that this protein corresponds to the correct linoleate isomerase fusion protein (data not shown).
  • the cells expressing the linoleate isomerase gene were harvested four hours after IPTG induction and analyzed to determine the location of the isomerase-His fusion protein.
  • Fig. 13 outlines the experimental protocol for the preparation of different protein fractions. Briefly, E. coli cells expressing the isomerase-His tag fusion protein were lysed in a non-denaturing buffer with lysozyme and broken by sonication. The total cell lysate was centrifuged at low speed to pellet the inclusion bodies. The crude inclusion bodies were washed twice with 0.25 % Tween 20 and 0.1 mM EGTA. The proteins retained in the washed pellets were highly insoluble aggregates of improperly folded peptides (inclusion bodies).
  • the supernatant generated by low speed centrifugation of the total cell lysate was subjected to an ultra centrifugation step to separate membrane (pellet) from soluble proteins.
  • Detergent was used to solubilize membrane proteins, which were then separated from other insoluble membrane components by ultra-centrifugation.
  • the total cell lysate and different protein fractions were analyzed on SDS gel and by Western blot. In the total cell lysate of E. coli cells expressing the isomerase gene, only the protein band between 60 and 70 kD can be seen after Coomassie staining. This protein band was recovered in the inclusion body fraction and was confirmed to be the isomerase-His tag fusion protein by Western blot.
  • the antibody did not cross-react with other proteins in the cell lysate of E. coli that did not contain the isomerase gene construct.
  • the amount of fusion protein in the soluble and membrane fractions was under the detectable limit.
  • the fusion protein in the inclusion body fraction was extensively washed with EGTA and Tween 20 to remove other contaminant proteins.
  • the purified peptide will be used to produce antibodies specific for the PYR8 linoleate isomerase.
  • Additional strategies for expressing a linoleate isomerase of the present invention include, but are not limited to: (1) deleting the single hydrophobic domain of the sequence to try to convert the isomerase into a functional soluble protein for use in determination of fusion protein synthesis, solubility and isomerase activity; (2) developing constructs for production of the isomerase in L. reuteri using both the native promoter and non-native inducible or constitutive promoters, including an isomerase-His tag fusion gene under the control of the isomerase native promoter; (3) cloning the promoter from the erythromycin resistance gene for control of isomerase gene expression in L.
  • reuteri ATCC 23272 reuteri ATCC 23272; and (4) knocking out the wild-type linoleate isomerase gene in the native L. reuteri PYR8 strain and recovering the activity by transforming the strain with the cloned isomerase gene.
  • a plasmid has been generated to knock out the wild-type gene which contains a nonfunctional isomerase gene interrupted by an erythromycin resistance gene as a selectable marker.
  • the forward primer corresponds to nucleotide positions 3678 through 3706 of nCLA 7U3 (SEQ ID NO:26), with a Ndel site containing the ATG start codon at the 5' end (lower case): S'catATGTATTATTCAAACGGGAATTATGAAGC-S'.
  • the reverse primer corresponds to nucleotide position 5579 through 5602 of the sequence nCLA 7113 (SEQ ID NO: 26) with a Bell site at the 5' end (lower case):
  • Recombinant plasmid DNA was digested with SacI to remove the E. coli portion of the vector, recircularized, and transformed into B. subtilis 23856.
  • the isomerase coding sequence was placed under the control of the Hpall promoter (Fig. 12, #1 construct) and its native ribosome-binding site was replaced by the counterpart in the vector.
  • Clones of transformants were grown to mid-log phase and thai harvested for biotransformation of linoleic acid.
  • No CLA was detected by GC analysis in the hexane extract of fatty acids.
  • the level of linoleic acid decreased drastically, being about 40% after a 3 hour incubation. The same results were observed with all sixteen B. subtilis clones tested.
  • this unknown product may be an intermediate of linoleic acid conjugation.
  • this product was incubated with . reuteri PYR8 cells or crude enzyme extracts, however, it could not be converted to CLA. It is possible that the intermediate has to be bound with the enzyme or membrane during the conjugation, and once it is released the conjugation could not be completed.
  • Further experiments include developing a series of constructs based on the vector pLATlO to explore the advantage of including the His tag (Fig. 12).
  • pLATlO is a plasmid that can be used to directly transform B. subtilis and B. licheniformis.
  • the LAT gene has the promoter, coding sequence and the terminator of the LAT gene encoding ⁇ - amylase. Also present is a signal peptide sequence for mobilizing proteins into or across the Bacillus membrane.
  • the isomerase coding sequence was placed under amylase promoter control as a fusion to its signal peptide.
  • the LAT signal sequence directs the protein into or across the membrane. Soluble proteins typically are secreted into the culture broth and in the process, the signal peptide is removed by specific proteases. Membrane protein would migrate to and integrate into the membrane. Since the hydrophobic domain of the isomerase peptide may function both as an uncleaved signal sequence and transmembrane segment in L.
  • construct #3 (Fig. 12) the entire coding sequence of the isomerase gene is fused to His tag at the C-terminus while in construct #4, the isomerase sequence without the hydrophobic domain is fused to His tag.
  • constructs #5 and #6 the secretion signal peptide is removed. With these new constructs, it can be determined whether the isomerase protein is synthesized in Bacillus cells and in which cellular fractions the protein is located.
  • P. acnes ATCC 6919 is the only microorganism known to produce tl0,cl2- CLA directly from linoleic acid.
  • Experiments described in Example 1 using whole cells confirmed the presence of a 10, 12-linoleate isomerase in this organism. Enzyme extracts were prepared by French Press.
  • Fig. 14 shows the formation of tl0,cl2-CLA from linoleic acid using whole cells of P. acnes. Cultures were grown anaerobically to stationary phase in a complex brain heart infusion medium, harvested and resuspended in the same medium containing 500 ppm linoleic acid. Cells were incubated aerobically with shaking at ambient temperature.
  • the level of linoleic acid decreased about 50% in 24 hours. About half of this missing linoleic acid could be detected as tlO,cl2-CLA. No c9,tll-CLA was observed. With prolonged incubation, the level of tlO,cl2-CLA changed only slightly, while nearly all remaining linoleic acid disappeared. At present it is unclear how linoleic acid is metabolized in this organism.
  • Linoleic acid may also be a substrate for enzymes other than the isomerase. Enzyme extracts were prepared by French Press and the extract fractionated as outlined in Fig. 15. Taking the total isomerase activity in fraction A as 100%, over 93% of the activity was detected in the soluble protein fraction (B). Less than 1 % of the isomerase activity was found in the washed pellet, or membrane fraction (C).
  • the P. acnes isomerase clearly is not a membrane protein, unlike the isomerase activities in L. reuteri PYR8 and other strains examined to date.
  • Isomerase activity using a crude soluble enzyme preparation, was not significantly affected by overnight dialysis.
  • a number of possible cofactors were tested for their effect on isomerase activity, including NAD, NADH, NADP, NADPH, FAD,
  • the effect of pH on enzyme activity in crude extracts was examined.
  • the isomerase activity exhibits a pH optimum centered around 6.8 (Fig. 16).
  • Fig. 17 shows a typical time course experiment using the crude isomerase extract as enzyme source. Generally, the isomerase was assayed using an endpoint assay after
  • Fig. 18 time course assay at different linoleic acid levels
  • Fig. 19 end point assay at different linoleic acid levels
  • the DEAE step was optimized further by altering the salt gradient program. Following a linear gradient to 0.175 M NaCI, the salt level was held at this level for 70 ml. The isomerase eluted at this point, after which time the gradient was continued to elute other proteins.
  • the isomerase binds very tightly to the phenyl HIC column, and is only released with ethylene glycol. A large number of other proteins were also released, however, with stepwise exposure to 20% ethylene glycol.
  • the HIC chromatography step was altered by use of an ethylene glycol gradient from 5 to 30% . This resulted in a somewhat sharper elution profile for the isomerase than previously obtained (results not shown).
  • N-terminal sequencing of the P. acnes linoleate isomerase has been completed.
  • the N-terminal amino acid is blocked, and therefore, N-terminal sequence cannot be determined directly.
  • the entire linoleate isomerase nucleic acid and amino acid sequence will be derived using methods described for the L. reuteri linoleate isomerase in Example 5, and as described below.
  • genomic DNA library is being created. Using a modified protocol for DNA isolation from Gram-positive bacteria, genomic DNA of good quality was isolated from P. acnes. After small-scale tests, genomic DNA was partially digested with Sau3AI, partially filled with dGTP and dATP, size selected by electrophoresis through agarose gel, and purified from agarose gel by electroelution. This purified DNA digest will be ligated to Xhol half-site arm of the BlueStar phage vector, packaged and plated. The quality of the library (titer and percentage of recombinant phage) will be tested. Oligonucleotide probes will be created based on the determination of the internal fragment sequences of the P. acnes linoleate isomerase and will be used to screen the library and isolate one or more clones for sequence analysis.
  • the following example describes the purification and characterization of a linoleate isomerase from Clostridium sporogenes.
  • C. sporogenes is capable of converting significant amounts of linoleic acid to CLA.
  • the linoleate isomerase from C. sporogenes appears to have activity levels and characteristics most similar to that of L. reuteri PYR8.
  • the following experiments describe the purification and characterization of the linoleate isomerase from this microorganism, with the goal to clone this isomerase gene, as has been described for L. reuteri in Example 5.
  • the cloned C. sporogenes isomerase gene activity and functionality will then be compared to the recombinant L. reuteri activity.
  • C. sporogenes ATCC 25762 was grown in a Brain Heart Infusion Broth (BHI) medium under anaerobic conditions. Bacterial growth was measured with a spectrophotometer at 600 nm. When cells were grown at 37°C, pH 7.5, stationary phase was reached after 6 hours incubation. Further incubation resulted in rapid lysis of the culture. Cultures were harvested, therefore, after about 6 hours growth. The cell pellet was washed with 0. 1 M Tris, pH 6.0, containing 15 mM NaCI. Biological transformation of CLA was performed by resuspending harvested cells in fresh growth medium containing 200 ppm linoleic acid.
  • BHI Brain Heart Infusion Broth
  • Fig. 23A-D shows a time course of biotransformation of linoleic acid by C. sporogenes. Resuspended cells were grown under aerobic (Figs. 23A & C) or anaerobic (B & D) conditions at room temperature
  • Tables 1 and 2 show the distribution of isomerase activity and protein concentration in fractions which were prepared with low salt (10mm NaCI) from frozen cells and with high salt (500mM NaCI) from fresh cells, respectively. Enzyme activity was detected in all fractions. The highest activity was found in the 45k/0.3% OTGP soluble fraction. It has been reported that detergents require high concentration of salt for effective solubilization of membrane proteins. Addition of NaCI in extract buffer resulted in increasing specific activity (Table 2), indicating the effectiveness of high salt. The specific activity was at least 50-fold higher in high salt detergent soluble fractions (Table 3) than in low salt detergent soluble fractions (Table 2). Conditions under which the active cultures are stored could also affect activity. These results suggested that the C. sporogenes linoleate isomerase has characteristics similar to the L. reuteri PYR8 membrane-associated enzyme.
  • the optimum pH was monitored by adjusting the pH from 5.0 to 9.0 using the 0.1M Tris buffer with 10 mM NaCI, ImM DTT and 40 ppm linoleic acid.
  • the optimum pH was found to be 7.5, 8.0 and 9.0 for incubating at 4°C, room temperature and 37°C, respectively (Fig. 25).
  • the concentration of linoleic acid was tested from 0 to 100 ppm (Fig. 26).
  • the optimum concentration for linoleic add was determined to be 40 ppm.
  • a time course study indicated that the activity responded linearly within 20 minutes and showed a slight decrease upon 60 minutes incubation at optimum pH, temperature and substrate concentration (Fig. 27).
  • the C. sporogenes isomerase was alternatively extracted by sonication in 0.1 M Tris, pH7.5, 10 mM NaCI, 2mM DTT and 10% glycerol. This extraction was of higher efficiency (about 20%) than that by French press. This is different from the isomerase isolated from L. reuteri, wherein it was observed that sonication resulted in a total loss of activity. Isomerase activity was higher in phosphate buffer, pH 7.5, than in Tris buffer, pH 7.5 (Fig. 28). The enzyme was most stable in phosphate buffer. The detergent soluble fraction was further purified by Method A, B or C, infra. Method A Experimental conditions for purification of the isomerase by DEAE-5PW chromatography have been established.
  • Fig. 29 gives an overview of the purification of the isomerase from OTGP solubilized protein.
  • the peak fractions (#48 to #51) contained 60% of the isomerase loaded on the column, resulting in a 6- fold purification to an average specific activity of 32.
  • the column was eluted further with 1M NaCI, and putative enzyme activity was detected by UV analysis (linoleic acid (LA) was apparently converted into products with spectra identical to CLA).
  • C. sporogenes linoleate isomerase is a membrane protein.
  • the detergent, octyl-thioglucopyranoside (OTGP) has been used successfully to solubilize isomerase.
  • OTGP octyl-thioglucopyranoside
  • OPTG and the solubilized enzyme precipitated slowly during purification at 4°C.
  • a nondenaturing detergent, Triton X- 100 with a high concentration of salt is commonly used to distinguish between peripheral and integral membrane proteins. No significant difference was found in the efficiency of the solubilization between 1 % Triton X-100 and 0.3 % OPTG. Less total protein was solubilized with a mixture of 0.1 % Triton X-100 and 0.3 % OPTG.
  • lysophosphatidylcholine LPC
  • CaCl 2 can activate enzymes, such as some nucleases.
  • Added CaCl 2 plus LPC has been demonstrated to stabilize detergent solubilized sodium channel membrane proteins. None of these positive effects was observed on the linoleate isomerase.
  • CaCl 2 decreased the enzyme activity in both Tris and phosphate buffer systems. At temperatures higher than 37°C, CaCl 2 had no effect on the activity, but the isomerase activity was reduced to 50% at the temperatures of 42°C and 60°C (Fig. 31).
  • Fig. 32 shows the effect of the iron-chelating agents, phenanthroline and
  • Fig. 36 The effect of the type of buffer was also significant. Tris buffer, potassium phosphate buffer, and Hepes buffer were compared, and the results are shown in Fig. 36. Phosphate buffer was the most effective in extraction and solubilization of the isomerase. This buffer produced a distinct increase in the activity obtained. In crude extracts, activity was about double that obtained with Tris, and in detergent soluble fractions a four- to seven-fold increase was measured. Further improvements (Fig. 37) were obtained by increasing the NaCI (20% increase in activity) and glycerol concentrations (30% increase).
  • the enzyme stability was compared at pH 7.5.
  • the isomerase was more stable in crude extracts than in detergent solubilized fractions (Fig. 38).
  • a half- life of 10, 11 and 13 days was measured in Tris, phosphate and Hepes crude extracts, respectively.
  • Increasing glycerol and salt concentration provided major improvements on stability, resulting in near full retention of activity for one week.
  • half- life of detergent solubilized isomerase was only three and six days in Tris and phosphate buffer, respectively.
  • Triton X-100 has a good performance as solubilizing agent for the isomerase, and the amount of protein solubilized increased with increasing Triton X-100 concentrations. Isomerase extraction was also enhanced at high salt concentration (500 mM NaCI). However, it was determined that enzyme activity was completely lost when the solution was dialyzed before ion exchange. The use of low salt concentration resulted in lower protein extraction from the membrane pellet, but similar enzyme activity and eliminates the requirement for the desalting step.
  • OG octyl glucoside
  • OG can be used to solubilize linoleate isomerase, this detergent is too expensive to use in large-scale isomerase purification.
  • the protocol to solubilize linoleate isomerase was modified to initially solubilize isomerase with OG, and then keep the enzyme solubilized with OTGP. the membrane fraction was solubilized with 1.5% OG in 50 mM potassium phosphate buffer at 15 °C. OG solubilized proteins were dialyzed against 20 mM potassium phosphate buffer, pH 7.5 , 10 mM NaCI, 2mM dithiothreitol and 0.3% OTGP.
  • Peak I which was eluted at lower ionic strength (0.18M NaCI), was observed for the first time. Both peaks catalyzed isomerization of linoleic acid to c9, tll-CLA, as determined by GC analysis of methyl ester products. Peak II was chosen for further purification.
  • This protocol can be used to purify sufficient C. sporogenes linoleate isomerase protein to determine the N-terminal sequence for the isomerase, and to subsequently clone and sequence the entire enzyme, as described for the L. reuteri linoleate isomerase described above.
  • the following example describes the optimization of growth conditions for L. reuteri PYR8. Fermentation work was concentrated on the optimization of growth conditions for L. reuteri PYR8. A fermentation medium that could consistently support cell growth well and isomerase production, thus eliminating the variability previously observed was pursued.
  • the vitamin mixture contained riboflavin, pantothenic acid, pyridoxal, nicotinic acid, folic acid, choline chloride, biotin and thiamine.
  • Difco yeast extract was successfully replaced by KAT yeast extract, and several industrial type nitrogen sources were tested as replacements for Peptone #3. These are summarized in Table 7.
  • the medium with 30 g/l yeast extract, 10 g/l Hy-Soy and 30 g/l glucose was chosen for further optimizations steps.
  • a temperature of 40°C was adopted as the preferred growth temperature and the medium containing 30 g/l yeast extract, 10 g/l Hy-Soy, 30 g/l glucose and 1.5 ml/l Tween, as the new base medium.
  • the reproducibility of the process was tested in triplicate fermentors. Higher concentrations of yeast extract, Hy-Soy and glucose were also compared at 40°C.
  • Example 12 The following example describes the determination of conditions to improve enzyme stability and performance and on testing the limitations of the biotransformation process.
  • Whole cells of L. reuteri PYR8 were used in all biotransformation experiments described below.
  • One aspect of the preservation of the enzyme activity is the handling of the cells immediately after harvesting and the determination of suitable storage conditions.
  • the preservation of activity in cells maintained in different buffers was investigated, and it was determined that reduced buffers such as TKM/EDTA/NaCl (50 mM Tris.HCl, 25 mM KC1, 5 mM MgCl 2 , 1.25 mM EDTA, 0.1 mM NaCI, pH 7.5) with 20 mM cysteine or 20 mM DTT preserved isomerase activity much better than other buffers or culture medium.
  • TKM/EDTA/NaCl 50 mM Tris.HCl, 25 mM KC1, 5 mM MgCl 2 , 1.25 mM EDTA, 0.1 mM NaCI, pH 7.5
  • Breakage buffer was selected as the medium of choice to perform the biotransformation because of the better enzyme stability. Cells can also be preserved prior to harvesting in the culture broth at the low pH reached at the end of the fermentation.
  • Linoleic acid was added as 99% LA, dissolved in propyleneglycol (100 mg/ml solution) or emulsified with 0.5, 5 or 30% lecithin.
  • the emulsion was prepared by blending the linoleic acid and the lecithin with the reaction medium before the addition of the cells. Linoleic acid was added at 1000 and 2000 ppm. The results indicated that there was no significant difference between adding the pure acid or the propyleneglycol solution, and that the reaction was slightly faster with both than when the acid was emulsified with lecithin (data not shown). High levels of lecithin seemed to negatively affect the final conversion.
  • the effect of substrate and product on the enzyme performance was also investigated, as well as the possibility of recycling the cells.
  • the effect of CLA on the reaction was studied by adding different concentrations of either a mixture of isomers (Sigma material, approximately 41% 9,11 isomer and 48% 10,12 CLA), or just 9,11 CLA (Matreya material, approximately 77% 9,11 CLA). Concentrations from 500 to 3000 ppm were tested. Some experiments were also performed recycling the broth from a previous biotransformation reaction with L. reuteri PYR8, resulting in an initial
  • Example 13 The following example describes a preferred biotransformation protocol.
  • Cells of Lactobacillus reuteri are grown in modified AV medium with 40 g/l yeast extract, 20 g/l Hy-soy and 40 g/l glucose (or other appropriate medium for other organisms) to a cell density of about 3-4 g/l dry cell weight.
  • modified AV medium with 40 g/l yeast extract, 20 g/l Hy-soy and 40 g/l glucose (or other appropriate medium for other organisms) to a cell density of about 3-4 g/l dry cell weight.
  • the biotransformation reaction should be preferably carried out at a temperature between 4°C and 8°C to maintain the enzyme activity.
  • the linoleic acid can be added as a 99% oil, as a component of another oil, as an oil phase, or dissolved in a cosolvent such as propylene glycol. It can be added at concentrations between 0.5 and 4 g/l. The addition should preferably be done in several steps of smaller amounts. To obtain higher CLA concentrations, it is also possible to add the cells in successive steps while the reaction proceeds. Under these conditions, and at these linoleic acid concentrations, conversion of linoleic acid to CLA between 80% and 100% is expected within 2 to 8 hours.
  • the following example describes the biotransformation of linoleic acid to 10, 12 CLA with P. acnes whole cells.
  • the objective of these studies was to begin the characterization of the behavior of the 10, 12 linoleic acid isomerase and to determine the conditions to enhance its performance.
  • P. acnes is a strict anaerobe for which growth in the medium currently used is very poor.
  • Some previous experiments suggested that P. acnes was able to further metabolize 10,12 CLA.
  • the new experiments also indicated this to be the case, but it seems to be a slow process which may depend on the conditions of the reaction. It must be noted that with the current cell concentration achieved in the culture, and the same bioconversion protocol used in the production of the 9,11 CLA isomer (10-fold concentration of the cells, resuspension in buffer, addition of linoleic acid dissolved in propyleneglycol), the reaction proceeds at a much lower rate than that of the 9,11 isomerase, and much lower conversions are achieved. The reaction was compared in culture medium vs.

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Abstract

La présente invention concerne une linoléate isomérase isolée, ainsi que son acide nucléique et sa séquence d'acide aminé. La présente invention concerne également une méthode permettant de produire de l'acide CLA à partir d'une huile, au moyen d'une cellule bactérienne immobilisée ou d'une linoléate isomérase isolée.
PCT/US1998/027612 1997-12-23 1998-12-23 Linoleate isomerase WO1999032604A1 (fr)

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JP2000525523A JP2002508929A (ja) 1997-12-23 1998-12-23 リノール酸イソメラーゼ
AU20150/99A AU2015099A (en) 1997-12-23 1998-12-23 Linoleate isomerase
EP98964935A EP1042451A4 (fr) 1997-12-23 1998-12-23 Linoleate isomerase

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US6861797P 1997-12-23 1997-12-23
US8956098P 1998-06-17 1998-06-17
US60/068,617 1998-06-17
US60/089,560 1998-06-17

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Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001009296A1 (fr) * 1999-07-30 2001-02-08 Monsanto Technology Llc. Sequences d'acides nucleiques codant pour des acides gras polyenoiques isomerase et leurs utilisations
WO2002010423A3 (fr) * 2000-08-02 2002-10-03 Dsm Nv Isolement d'huiles microbiennes
WO2003080850A1 (fr) * 2002-03-27 2003-10-02 Valio Ltd Procede de preparation d'acide linoleique conjugue
WO2004005442A1 (fr) * 2002-07-03 2004-01-15 Basf Plant Science Gmbh Procede de production d'acides gras polyinsatures conjugues comportant au moins deux liaisons doubles dans des plantes
US6960456B1 (en) 1999-11-19 2005-11-01 Valio Ltd. Method for preparing conjugated linoleic acid
US7223543B2 (en) 2001-06-08 2007-05-29 Teagasc Dairy Products Research Centre Conjugated linoleic acid isomerase and a process for the production of conjugated linoleic acid
WO2007074010A1 (fr) 2005-12-24 2007-07-05 Teagasc Dairy Products Research Centre Procede de production de l’acide trans-10, cis 12 octadecadienoique
WO2008119735A1 (fr) * 2007-04-02 2008-10-09 Georg-August-Universität Göttingen Procédé de fabrication d'acide gras hydroxy
US7700833B2 (en) 2002-03-01 2010-04-20 Cornell University Process for the production of unsaturated fatty acids
US7960599B2 (en) 2003-01-13 2011-06-14 Elevance Renewable Sciences, Inc. Method for making industrial chemicals
CN102093994A (zh) * 2010-12-07 2011-06-15 淮阴工学院 一种同时纯化和固定化亚油酸异构酶的方法
US9745539B2 (en) 2013-12-20 2017-08-29 MARA Renewables Corporation Methods of recovering oil from microorganisms
US10342772B2 (en) 2013-12-20 2019-07-09 Dsm Ip Assets B.V. Processes for obtaining microbial oil from microbial cells
US10364207B2 (en) 2013-12-20 2019-07-30 Dsm Ip Assets B.V. Processes for obtaining microbial oil from microbial cells
US10392578B2 (en) 2010-06-01 2019-08-27 Dsm Ip Assets B.V. Extraction of lipid from cells and products therefrom
US10472316B2 (en) 2013-12-20 2019-11-12 Dsm Ip Assets B.V. Processes for obtaining microbial oil from microbial cells
US11001782B2 (en) 2013-12-20 2021-05-11 Dsm Nutritional Products Ag Methods of recovering oil from microorganisms
US11124736B2 (en) 2013-12-20 2021-09-21 Dsm Ip Assets B.V. Processes for obtaining microbial oil from microbial cells
US12104139B2 (en) 2013-12-20 2024-10-01 Dsm Ip Assets B.V. Processes for obtaining microbial oil from microbial cells

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JP2008162928A (ja) * 2006-12-27 2008-07-17 Nagasakiken Koritsu Daigaku Hojin 脂肪蓄積抑制剤

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US5674901A (en) * 1995-06-01 1997-10-07 Wisconsin Alumni Research Foundation Methods of treating animals to maintain or increase CD-4 and CD-8 cell populations

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DATABASE MPSRCH GENBANK 1 January 1900 (1900-01-01), SAKO T, TSUCHIDA N: "NUCLEOTIDE SEQUENCE OF THE STAPHYLOKINASE GENE FROM STAPHYLOCOCCUS AUREUS", XP002944399, Database accession no. X00127 *
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See also references of EP1042451A4 *

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001009296A1 (fr) * 1999-07-30 2001-02-08 Monsanto Technology Llc. Sequences d'acides nucleiques codant pour des acides gras polyenoiques isomerase et leurs utilisations
US6960456B1 (en) 1999-11-19 2005-11-01 Valio Ltd. Method for preparing conjugated linoleic acid
WO2002010423A3 (fr) * 2000-08-02 2002-10-03 Dsm Nv Isolement d'huiles microbiennes
US7431952B2 (en) 2000-08-02 2008-10-07 Dsm Ip Assets B.V. Isolation of microbial oils
US7223543B2 (en) 2001-06-08 2007-05-29 Teagasc Dairy Products Research Centre Conjugated linoleic acid isomerase and a process for the production of conjugated linoleic acid
EP1399569B1 (fr) * 2001-06-08 2008-09-10 Teagasc Dairy Products Research Centre Isomerase d'acide linoleique conjugue et procede de production de cet acide linoleique conjugue
US7700833B2 (en) 2002-03-01 2010-04-20 Cornell University Process for the production of unsaturated fatty acids
WO2003080850A1 (fr) * 2002-03-27 2003-10-02 Valio Ltd Procede de preparation d'acide linoleique conjugue
WO2004005442A1 (fr) * 2002-07-03 2004-01-15 Basf Plant Science Gmbh Procede de production d'acides gras polyinsatures conjugues comportant au moins deux liaisons doubles dans des plantes
US7960599B2 (en) 2003-01-13 2011-06-14 Elevance Renewable Sciences, Inc. Method for making industrial chemicals
WO2007074010A1 (fr) 2005-12-24 2007-07-05 Teagasc Dairy Products Research Centre Procede de production de l’acide trans-10, cis 12 octadecadienoique
WO2008119735A1 (fr) * 2007-04-02 2008-10-09 Georg-August-Universität Göttingen Procédé de fabrication d'acide gras hydroxy
US10392578B2 (en) 2010-06-01 2019-08-27 Dsm Ip Assets B.V. Extraction of lipid from cells and products therefrom
CN102093994A (zh) * 2010-12-07 2011-06-15 淮阴工学院 一种同时纯化和固定化亚油酸异构酶的方法
US9745538B2 (en) 2013-12-20 2017-08-29 MARA Renewables Corporation Methods of recovering oil from microorganisms
US10342772B2 (en) 2013-12-20 2019-07-09 Dsm Ip Assets B.V. Processes for obtaining microbial oil from microbial cells
US10364207B2 (en) 2013-12-20 2019-07-30 Dsm Ip Assets B.V. Processes for obtaining microbial oil from microbial cells
US9745539B2 (en) 2013-12-20 2017-08-29 MARA Renewables Corporation Methods of recovering oil from microorganisms
US10472316B2 (en) 2013-12-20 2019-11-12 Dsm Ip Assets B.V. Processes for obtaining microbial oil from microbial cells
US10745642B2 (en) 2013-12-20 2020-08-18 MARA Renewables Corporation Methods of recovering oil from microorganisms
US11001782B2 (en) 2013-12-20 2021-05-11 Dsm Nutritional Products Ag Methods of recovering oil from microorganisms
US11124736B2 (en) 2013-12-20 2021-09-21 Dsm Ip Assets B.V. Processes for obtaining microbial oil from microbial cells
US11746363B2 (en) 2013-12-20 2023-09-05 MARA Renewables Corporation Methods of recovering oil from microorganisms
US12104139B2 (en) 2013-12-20 2024-10-01 Dsm Ip Assets B.V. Processes for obtaining microbial oil from microbial cells

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AU2015099A (en) 1999-07-12
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JP2002508929A (ja) 2002-03-26

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