A kind of neutral proteinase production bacterial strain and its application
Technical field
The invention belongs to gene engineering technology field, and in particular to a kind of neutral proteinase production bacterial strain and its application.
Background technology
Protease is the general name of the class of enzymes of aminosal peptide bond.In the way of its hydrolyzed peptide, it can be classified as
Endopeptidase and the class of exopeptidase two.Endopeptidase by protein molecule inner cut-out, exopeptidase from the free amine group of protein molecule or
The end of carboxyl is one by one by peptide bond hydrolysis, and the amino acid that dissociates, and the former is aminopeptidase, and the latter is carboxypeptidase.By its work
Protease, can be divided into serine protease, thiol protease, metalloproteinases and aspartic acid by property center and optimum pH again
Protease.By the optimum pH of its reaction, it is divided into acid protease, neutral proteinase and alkali protease.
Protease is widely present in animal in incident, plant stem-leaf, fruit and microorganism.Microbial protease, mainly by
Mould, bacterium, secondly produced by yeast, actinomyces.
Protease has been widely used in leather, fur, silk, medicine, food, brewageed etc..The depilation of leather industry
Protease is largely utilized with softening, both saves the time, improves labour health condition again.Protease can be additionally used in natural silk degumming,
Tenderization, drinks clarification.Can clinically make it is medicinal, such as use pepsin treatment indigestion, with acidic protein enzyme treatment branch
Tracheitis, and controlled with serous coat adhesion between the purification of trypsase, chymotrypsin to the suppurative wound of surgery and thoracic cavity
Treat, it may also be used for tissue treatment is turned into individual cells, carries out cell and tissue structrue.Enzymatic laundry powder is the new production in detergent
Product, containing alkali protease, the bloodstain and albumen dirt on clothing can be removed, but using when be careful not to contact skin, in order to avoid damage
Hinder the protein of skin surface, cause the allergic phenomenas such as fash, eczema.
The research for neutral proteinase is also seldom at present, is mainly being related to the advanced flavouring of production and food nutrient fortifying
Agent, and the manufacture field such as leather depilation, softening, wool silk scouring.
The content of the invention
It is an object of the invention to provide a kind of neutral proteinase production bacterial strain and its application.The present invention is by by aspergillus oryzae
(Aspergillus oryzae)Neutral protease gene be transferred to trichoderma reesei(Trichoderma reesei)In, build
To trichoderma reesei engineered strain, energy efficient secretory expression neutral proteinase, food and leather processing field can be widely applied to.
One aspect of the present invention provides a kind of trichoderma reesei, and it carries the recombinant vector of expression neutral proteinase.
The neutral proteinase is
(a)Amino acid sequence is SEQ ID NO:1 enzyme;
(b)(a)In amino acid on substitution, missing or addition one occurs or several amino acid obtain, in having
The enzyme of property proteinase activity.
The coding nucleotide sequence of the neutral proteinase is SEQ ID NO: 2.
Present invention also offers the application of above-mentioned trichoderma reesei.
The high efficiency recombinant expressed neutral proteinase of trichoderma reesei engineering bacteria energy that present invention purchase is built, fermentation enzyme activity reach 5000U/
mL.The most suitable action pH of neutral proteinase of the present invention is 7.0, and more than 60% enzymatic activity can be kept in pH50-8.0;
Optimum temperature is 65 DEG C, and more than 85% enzymatic activity can be kept at 55-70 DEG C.The neutral proteinase can answer extensively
For food and leather processing field.Wherein, it is up to using the collagen in the neutral proteinase hydrolysis pigskin, percent hydrolysis
68%, efficiency high, pollution is few, and application effect is good.
Brief description of the drawings
Fig. 1 is neutral proteinase action pH of the present invention-relative enzyme activity curve.
Fig. 2 is neutral proteinase operative temperature of the present invention-relative enzyme activity curve.
Embodiment
The routine techniques and method that the present invention has used genetic engineering and biology field uses, such as
MOLECULAR CLONING:A LABORATORY MANUAL, 3nd Ed. (Sambrook, 2001) and CURRENT
Described method in PROTOCOLS IN MOLECULAR BIOLOGY (Ausubel, 2003).These generality are with reference to text
Offer and provide definition well known by persons skilled in the art and method.But this be not meant to limit the invention to it is described
Any specific method, experimental program and reagent, because they can change.
Unless being separately construed as limiting herein, whole technical terms and scientific terminology used herein have to be led belonging to the present invention
The identical meanings that the common counting personnel in domain are generally understood.DICTIONARY OF MICROBIOLOGY AND MOLECULAR
BIOLOGY, 3nd Ed. (Singleton et al., 2006) and COLLINS DICTIONARY BIOLOGY (Hale
Et al., 2003) the general explanation of many terms used in the present invention is provided for technical staff.
Unless otherwise mentioned, nucleic acid is write from left to right by 5 ' to 3 ' directions;Amino acid is the side to carboxyl by amino
To writing from left to right.
As used herein, term " restructuring " represents the cell, core when being used to refer to cell, nucleic acid, albumen or carrier
Acid, albumen or carrier are by importing heterologous nucleic acids or albumen or being modified by changing natural acid or albumen.Therefore,
For example, recombinant cell be expression in the cell of natural (non-recombinant) form not it has been found that gene, or the natural base of expression
Cause.
Term " protein " and " polypeptide " are interchangeable herein.Traditional list of amino acid residue is used herein
Letter or three-letter codes.
As used herein, term " gene " refers to the DNA fragmentation for participating in production polypeptide, including the area before and after code area
Domain, and respectively encode the insetion sequence (introne) between fragment (extron).
Term " nucleic acid " includes DNA, RNA, single-stranded or double-stranded, and their chemical modification object.
Term " nucleic acid " and " polynucleotides " are interchangeable herein.
Term " carrier " refers to the polynucleotide sequence for being designed to that nucleic acid is imported to one or more cell types.Carrier
Including cloning vector, expression vector, shuttle vector, plasmid, phasmid, sequence box and the like.
Term " expression vector " represents the DNA constructions for including DNA sequence dna, and the DNA sequence dna is connected to by steerable
The suitable control sequence that the DNA is expressed in suitable host can be influenceed.Such control sequence can include completing transcription
Promoter, the operon sequence of optional control transcription, encode the sequence of suitable ribosome bind site, enhancer on mRNA
And the sequence of the termination of control transcription and translation.
Term " promoter " represents to participate in combining the regulating and controlling sequence that RNA polymerase is transcribed with promotor gene.Promoter can
To be inducible promoter or constitutive promoter.
With another sequence there is the polynucleotides of the sequence identity of a certain percentage or polypeptide to refer to, comparing the two
The base of the percentage or amino acid residue are identicals during sequence.
Because genetic code is degeneracy, it is possible to specific amino acid is encoded using more than one codon,
The present invention includes encoding the polynucleotides of specific amino acid sequence.
Term " host strain " or " host cell " refer to the suitable host of expression vector or DNA constructions, the expression
Carrier or DNA constructions include the polynucleotides of the encoding lipase of the present invention.Specifically, host strain is preferably thread
Fungal cell.The host cell can be wild-type filamentous fungal host cells or genetically modified host cell.Term
" host strain " or " host cell " refers to the cell karyoplast as caused by filamentous fungal strains cell.
The present invention is described in detail with reference to specific embodiment.
The clone of the protease gene of embodiment 1
With aspergillus oryzae(Aspergillus oryzae)Genome DNA is template, is expanded using upstream and downstream primer.
PCR amplification conditions are 95 DEG C of 4min;94℃ 30S;30 circulations of 55 DEG C of 40S, 72 DEG C of 1min;72℃ 7min.Gel returns
Kit recovery pcr amplification product is received, send Beijing Hua Da gene to carry out sequencing analysis amplified production.As a result show, reclaim
To the nucleotides sequence of amplified production be classified as SEQ ID NO:2, its amino acid sequence encoded is SEQ ID NO:1.Will be above-mentioned
Sequence compares analysis by NCBI Blast and found, SEQ ID NO:1 with the protease amino acid sequence similitude of aspergillus oryzae most
Height, it is 83%, is a new allele.
The trichoderma reesei of embodiment 2(Trichoderma reesei)The structure of engineered strain
The amplified production reclaimed in embodiment 1 is connected to pMD18-T carriers, obtains cloning vector pT-Pro plasmids, so
Double digestion is carried out with NcoI and KpnI afterwards, reclaims TR fragments;Take 2 μ l recovery products and NcoI and KpnI double digestion pKDN-5 carriers
Connection imports bacillus coli DH 5 alpha overnight, obtains recombinant expression plasmid pKDN-Pro.
Trichoderma reesei mycelium is inoculated in PDA plate, grown 4 days;The bacterium colony for cutting the cm of diameter about 3 is placed in about YEG
(0.5% dusty yeast, 1% glucose)In fluid nutrient medium, 30 DEG C, 200 rpm shaken cultivations stay overnight;Bacterium is collected by filtration in multilayer gauze
Silk;Mycelia is placed in and fills 10-20 ml cracking enzyme liquids(Sigma L1412)Digest 2-3 hours;Enzymolysis liquid is taken out, adds 0.7
M NaCl solutions, are jiggled, and are filtered in three layers of sterilizing lens wiping paper, are collected filtrate, 3000 rpm, are centrifuged 10 min;Abandon
Clearly, 10-20 ml STC liquid is added(20% sucrose, 50mM Tris-Cl, 50mM CaCl2)Suspend, 3000 rpm, centrifuge 10 min;
Add appropriate STC to suspend to dispense(150 μ l/ are managed, and 108Individual/ml).
Take 2 μ g pKDN- Pro DNA to be added in 150 μ l protoplasts, be subsequently added into 500 μ l 25%PEG and gently mix
It is even, it is stored at room temperature 25 min;Then divide 2-3 times and add 1ml 25%PEG again, gently mix, be stored at room temperature 25min, protoplast
45-55 DEG C of upper strata semisolid culturemedium is cooled to after being added to 50 ml or so fusings(0.1%MgSO4, 1%KH2PO4, 0.6%
(NH4)2SO4, 1% glucose, 18.3% sorbierite, 0.35% agarose), poured into after gently mixing containing 100 μ g/ml hygromycin
Subfoundation culture medium flat plate(2% glucose, 0.5% (NH4)2SO4, 1.5%KH2PO4, 0.06%MgSO4, 0.06%CaCl2,
1.5% agar), 28 DEG C of dark culturing a couple of days to transformants grow.Wherein one plant of positive transformant is named as trichoderma reesei
(Trichoderma reesei)Pro-1.
Embodiment 3 is fermented and zymologic property measure
Trichoderma reesei Pro-1 is inoculated in MM fermentation mediums(1.5% glucose, 1.7% lactose, 2.5% corn steep liquor,
0.44%(NH4)2SO4, 0.09%MgSO4, 2%KH2PO4, 0.04%CaCl2, 0.018% Tween-80,0.018% trace element,
0.018% polypropylene glycol -2000)Culture, 28 DEG C are cultivated 48 hours, are then cultivated 48 hours for 25 DEG C;8 layers of yarn of gained zymotic fluid
Cloth filters, and filtrate centrifuges 10 min under the conditions of 14000 g, collects supernatant;By supernatant in the SDS-PAGE that concentration is 12%
Electrophoresis detection is carried out on glue, occurs a protein band at 38kDa or so places, molecular weight is consistent with prediction, as recombinantly expresses
Protease.
Proteinase activity assay method is as follows:
With the vigor of folin's methods measure protease, the solution used includes:Forint uses solution(A commercially available forint
Solution mixes with two parts of water, shakes up), sodium carbonate liquor(42.4 g/L), trichloroacetic acid(65.4 g/L), gradient pH value buffering
Liquid, casein solution(10.0 g/L).Course of reaction is as follows:1ml enzyme liquids are added in test tube, 40 DEG C of warm bath 2min, add junket egg
White solution 1ml, 40 DEG C of warm bath 10min after shaking up, adds 2ml solution of trichloroacetic acid, shakes up(Blank control first adds three chloroethenes
Acid, add casein solution).Static 10min is taken out, qualitative filter paper filters at a slow speed.1ml filtrates are taken, add sodium carbonate liquor
5ml, Folin reagent is added 40 DEG C of colour developing 20min, in 680nm wavelength, absorbance to be determined with 10mm cuvettes using solution 1ml.
The definition of protease activity unit of force is 1g solid enzyme powders(Or 1 ml liquid enzymes), in certain temperature and pH value condition
Under, 1min caseinhydrolysates produce 1 μ g tyrosine, as 1 enzyme activity unit.
Enzyme activity assay is carried out to trichoderma reesei engineering bacterium fermentation liquid supernatant of the present invention using above-mentioned detection method, as a result shown
Show, zymotic fluid enzyme activity is up to 5000U/mL, illustrates the protease for the engineering bacteria energy efficient secretory expression aspergillus oryzae that the present invention is built.
(1)Optimal pH is analyzed
It is respectively 3.0,4.0,5.0,6.0,7.0,8.0,9.0,10.0,11.0 buffer solution with pH value, in temperature 50 C
Under the conditions of determine enzyme activity, using highest enzyme activity as 100%, calculate relative enzyme activity, be pH- with respect to enzyme activity curve, as a result as shown in figure 1,
The optimal pH of protease of the present invention is 7.0, is a neutral proteinase, and more than 60% enzyme can be kept in pH50-8.0
Activity.
(2)Optimum temperature is analyzed
Respectively at 30 DEG C, 35 DEG C, 40 DEG C, 45 DEG C, 50 DEG C, 55 DEG C, 60 DEG C, 65 DEG C, 70 DEG C, 75 DEG C, 80 DEG C, 85 DEG C, 90
DEG C, enzyme activity is determined under conditions of pH 7.0, using highest enzyme activity as 100%, calculates relative enzyme activity, does temperature-relative enzyme activity curve.
As a result as shown in Fig. 2 the optimum temperature of neutral proteinase of the present invention is 65 DEG C, more than 85% can be kept at 55-70 DEG C
Enzymatic activity.
Application of the neutral proteinase of embodiment 4 in collagen polypeptide is prepared
The present invention utilizes above-mentioned neutral protein ferment treatment pigskin, and collagen polypeptide is prepared, and yield is high, and pollution is small.
Specific embodiment is as follows:
1)The pre-treatment of pigskin
Fresh porcine skin is cleaned, strikes off the grease of pig skin surfaces after removing dirt;Appropriate water is added, is heated to 100 DEG C,
Keep 5min;Cooked pigskin is taken out, the fat on its surface is scraped off with knife after slightly cool, pulls out pig hair;Be then cut into 10mm ×
The pigskin block degreasing of 10mm sizes;
2)Saponification method degreasing
Degreasing agent is Na2CO3, 40 DEG C of temperature, the min of time 40, refrigerator freezing saves backup;
3)Enzymolysis prepares collagen polypeptide technique
The pigskin of pre-treatment is added into deionized water, tune pH value is 7.0-7.5, adds 1%-2% neutrality of the present invention
Protease, steady temperature hydrolysis 1h, the min enzyme deactivations of boiling water bath 10, centrifugation discard sediment.
The percent hydrolysis that above-mentioned Collagen Protein From Pig Skin is determined using formol titration is about 68%, it is seen that in of the present invention
Property protease can be widely used for the production of collagen polypeptide.
SEQUENCE LISTING
<110>Qingdao Weilan Biology Group Co., Ltd.
<120>A kind of neutral proteinase production bacterial strain and its application
<160> 2
<170> PatentIn version 3.5
<210> 1
<211> 353
<212> PRT
<213> protease enzyme sequence
<400> 1
Met Arg Phe Ile Pro Val Ser Phe Leu Leu Leu Pro Leu Ala Pro Ala
1 5 10 15
Leu Lys Pro Leu Pro Val Glu Val Ala Gly Ser Pro Glu Gly Leu Asp
20 25 30
Val Thr Val Arg Lys Val Gly Asn Pro Arg Ile Lys Ala Val Val Lys
35 40 45
Asn Thr Gly Ser Glu Asp Val Thr Phe Val His Leu Lys Leu Leu Lys
50 55 60
Asp Ala Ala Pro Val Pro Lys Val Phe Leu Phe Arg Asn Ala Thr Glu
65 70 75 80
Val Gln Phe Gln Gly Leu Lys Gln Arg Leu Ile Ser Lys Gly Phe Ser
85 90 95
Asp Asp Pro Phe Arg Thr Leu Ala Pro Gly Ala Thr Ile Glu Asp Glu
100 105 110
Leu Glu Thr Ala Ser Thr Ser Glu Leu Ser Glu Gly Gly Thr Ile Thr
115 120 125
Thr Lys Ser Asn Gly Leu Val Pro Ile Thr Thr Asp Asn Lys Val Thr
130 135 140
Gly Tyr Val Pro Phe Ser Ser Asn Glu Leu Ser Val Asp Val Asp Glu
145 150 155 160
Ala Glu Ala Ala Ser Val Thr Gln Ala Val Lys Ile Leu Glu Leu Arg
165 170 175
Thr Lys Val Thr Ser Cys Ser Gly Ser Arg Leu Ser Ala Leu Gln Thr
180 185 190
Ala Leu Arg Asn Thr Val Ser Leu Ala Arg Ala Ala Ala Thr Ala Ala
195 200 205
Gln Ser Gly Ser Ser Ser Arg Phe Gln Glu Tyr Phe Lys Thr Thr Ser
210 215 220
Ser Pro Thr Arg Ser Thr Val Val Pro Arg Leu Asn Ala Val Ala Lys
225 230 235 240
Glu Ala Ala Ser Thr Ser Ser Gly Ser Thr Thr Tyr Tyr Cys Ser Asp
245 250 255
Val Tyr Gly Tyr Cys Ser Ser Asn Val Leu Ala Tyr Thr Leu Pro Ser
260 265 270
Tyr Asn Ile Ile Ala Asn Cys Asp Leu Asn Tyr Ser Tyr Leu Ser Asp
275 280 285
Leu Thr Ser Thr Cys His Ala Gln Glu Lys Ala Ser Thr Thr Leu His
290 295 300
Glu Phe Pro His Pro Pro Gly Val Ser Thr Pro Gly Thr Asp Asp Phe
305 310 315 320
Gly Ser Gly Tyr Ser Ala Ala Thr Ser Phe Arg Ala Ser Gln Ala Leu
325 330 335
Leu Asn Ala Glu Thr Ser Pro Leu Phe Ala Asn Ala Val Lys Leu Lys
340 345 350
Cys
<210> 2
<211> 1062
<212> DNA
<213> protease gene sequence
<400> 2
atgcgtttca ttcctgtctc ctttcttctt ttgccccttg caccggctct caaacccctt 60
cctgtagagg ttgccggtag tcccgaaggt cttgatgtga ctgttaggaa ggtgggaaat 120
cctcggatca aggccgtggt aaagaacact ggcagcgagg atgtcacctt tgtgcacctc 180
aaattgttga aagatgccgc tccggtgccg aaagtttttc tgttccgcaa tgcgaccgag 240
gttcaattcc agggactcaa gcagcgtctt atctccaaag gtttttccga tgatcctttc 300
agaactcttg cccctggtgc tactatcgag gacgagctcg aaaccgcaag tactagtgaa 360
ctgtccgagg gtggtaccat cacgaccaaa agcaacggtt tagtacctat taccaccgat 420
aacaaggtca ctggatacgt tccattctcc tcgaacgagc tctccgttga tgtagatgaa 480
gctgaggccg cgagtgttac tcaagcagtt aagatcctgg agctccgcac caaggtcact 540
tcctgctctg gcagcagatt gtcggccctt cagactgctc tgagaaacac agtctctttg 600
gcacgtgcag ctgctactgc cgcgcagtcg ggatcttcct cccgtttcca ggagtatttc 660
aagacgacat ccagccccac ccgtagcacc gttgttcctc gcctgaacgc cgttgctaag 720
gaggccgcgt cgacctcttc gggaagtacc acgtactact gcagcgacgt gtatggatac 780
tgcagctcca acgtgcttgc gtataccctt ccgtcttata acatcatcgc caactgcgac 840
ctcaactatt cctatctttc ggacctgact agcacctgcc atgctcaaga aaaggcctcc 900
accaccctgc atgagttccc tcaccccccc ggtgtgtcca cccctggcac tgacgacttt 960
ggatctggat actcggctgc cacctccttc agggccagtc aggctctgct gaatgccgaa 1020
acctctccct tgtttgccaa cgctgtcaag ctcaagtgtt ag 1062