EP1155130A2 - Glucose-dehydrogenase-fusionsproteine und ihre verwendung in expressionssystemen - Google Patents

Glucose-dehydrogenase-fusionsproteine und ihre verwendung in expressionssystemen

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Publication number
EP1155130A2
EP1155130A2 EP00903672A EP00903672A EP1155130A2 EP 1155130 A2 EP1155130 A2 EP 1155130A2 EP 00903672 A EP00903672 A EP 00903672A EP 00903672 A EP00903672 A EP 00903672A EP 1155130 A2 EP1155130 A2 EP 1155130A2
Authority
EP
European Patent Office
Prior art keywords
protein
recombinant
gicdh
fusion protein
expression
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP00903672A
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German (de)
English (en)
French (fr)
Inventor
Winfried Linxweiler
Christa Burger
Oliver Pöschke
Uwe Hofmann
Andrea Wolf
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Merck Patent GmbH
Original Assignee
Merck Patent GmbH
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Publication date
Application filed by Merck Patent GmbH filed Critical Merck Patent GmbH
Publication of EP1155130A2 publication Critical patent/EP1155130A2/de
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K19/00—Hybrid peptides, i.e. peptides covalently bound to nucleic acids, or non-covalently bound protein-protein complexes
    • 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
    • C12N9/0004—Oxidoreductases (1.)
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K14/00—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
    • C07K14/81—Protease inhibitors
    • C07K14/815—Protease inhibitors from leeches, e.g. hirudin, eglin
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K2319/00—Fusion polypeptide
    • 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
    • C12N2799/00—Uses of viruses
    • C12N2799/02—Uses of viruses as vector
    • C12N2799/021—Uses of viruses as vector for the expression of a heterologous nucleic acid

Definitions

  • the invention relates to new recombinant fusion proteins which contain, as a component, a protein sequence with the biological activity of glucose dehydrogenase (GIcDH) and their use for the simple and efficient detection of any proteins / polypeptides, preferably serving as fusion partners, or for the rapid optimization of expression systems which said proteins / polypeptides are able to express.
  • GIcDH glucose dehydrogenase
  • the GIcDH or the sequence that exhibits the biological activity of GIcDH, takes on the role of a marker or detector protein.
  • a specialty of this enzyme is its exceptional stability against denaturing agents such as SDS.
  • GIcDH as a marker or detector protein shows an undiminished enzymatic activity even after the reducing and denaturing conditions of SDS-PAGE gels. Fusion proteins containing GIcDH can therefore be detected with a sensitive enzymatic reaction based on this surprising behavior. By labeling with GIcDH, the desired expressed protein can also be detected quickly, cheaply and effectively.
  • GIcDH protein / polypeptide fusion proteins can be expressed in higher yield and stability than without GIcDH.
  • Corresponding fusion proteins per se can thus be used for the production and production of proteins / Serve polypeptides.
  • the in vivo expression of recombinant proteins plays an increasingly important role in biotechnology.
  • the ability to obtain, purify and detect cloned gene products from pro- and eukaryotic expression systems such as bacteria, yeast, insect or mammalian cells is also often used for studies of protein structure and function, of protein-protein and protein DNA interactions as well as antibody production and mutagen nese used.
  • pro- and eukaryotic expression systems such as bacteria, yeast, insect or mammalian cells
  • recombinant DNA technology it is possible to specifically change natural proteins so that their function is improved or varied.
  • the recombinant proteins are synthesized in constantly evolving expression systems, the optimization of which can take place at the most varied places in the system.
  • the entire process of recombinant protein synthesis can be divided into two sections.
  • a first step the molecular biological gene isolation and expression of the target protein takes place and in the subsequent step the detection and purification from the recombinant cells or their growth medium.
  • the gene of a protein is cloned into an expression vector provided for this purpose, then introduced into a host cell (pro or eukaryote cell) and expressed there.
  • Bacterial cells prove to be simple and inexpensive systems that deliver high yields.
  • the gram-negative bacterium E. coli is most often used as the host cell.
  • the aim of the expression of foreign genes in E. coli is to obtain the largest possible amount of biologically active, recombinant proteins, the so-called overexpression. It is known that foreign eukaryotic proteins can lose their biological activity through aggregation, as inclusion bodies, through incorrect folding or proteolytic degradation. One way of avoiding these frequently occurring difficulties is to remove the expressed proteins from the cell as secretion proteins or to use so-called fusion proteins, by means of which insoluble recombinant proteins can be present in soluble form in the cell.
  • proteins are mostly expressed in eukaryotic cells.
  • the post-transcriptional modifications important for the function and the correct compartmentalization can take place there.
  • proteins important for correct folding and processing Eukaryotic expression systems are also suitable for the expression of larger proteins and of proteins which require post-transcriptional modifications such as SS bridging, glycosylation, phosphorylation, etc. for correct folding. Since these systems are generally complex and expensive and the expression rate is lower than that of E.coli, it is particularly important to have a detection system that is fast, secure, sensitive and inexpensive.
  • a sensitive detection system is necessary to determine the correct expression, the amount expressed, the molecular weight and the functional activity of the fusion protein formed.
  • the number of functionally unknown proteins is increasing rapidly and it is becoming increasingly important to develop fast and inexpensive detection systems for this.
  • Most gene fusion systems use immunological methods such as e.g. B. the "enzyme-linked immunosorbent assay” (ELISA) or the Western blot, in which recombinantly formed fusion proteins are detected with the help of specific antibodies.
  • ELISA enzyme-linked immunosorbent assay
  • Western blot in which recombinantly formed fusion proteins are detected with the help of specific antibodies.
  • Corresponding fusion proteins not only have the described advantage that the foreign protein can be easily detected and analyzed indirectly, but they often make it possible to express the desired protein in higher yields than would be the case without its fusion partner.
  • Each fusion partner has advantages in a certain expression system, which he is often able to transfer to the other partner. For example, the sensitivity of some proteins to protolytic degradation can be reduced if it is present as a fusion protein. Fusion proteins also often have more favorable solubility and secretion properties than the individual components. There are therefore numerous reasons for performing gene fusions for the expression of recombinant proteins in heterologous hosts.
  • test systems differ considerably in time, throughput and sensitivity.
  • fusion proteins Two types can be distinguished for the purposes mentioned above. Firstly, fusion proteins, which consist of the desired protein and a mostly short oligopeptide. This oligopeptide ("tag”) acts as a marker or recognition sequence for the desired protein. In addition, one day can make cleaning easier.
  • tag oligopeptide
  • His tag which consists of a peptide sequence with six successive histidine residues, which is linked directly to the recombinant protein. With the help of the attached His residue, the fusion protein can be easily purified via a metal affinity column (Smith et al., 1988). This His tag is easily detected with the aid of the highly specific monoclonal antibody His-1 (Pogge v. Strandmann et al., 1995).
  • GFP green fluorescent protein
  • Aepuorea victoria Another marker used in fusion proteins is GFP, a "green fluorescent protein” (GFP) from the jellyfish Aepuorea victoria, which is used as a bioluminescent protein in various biotechnological applications (Kendali and Badminton, 1998; Chalfie et al. , 1994; Inouye et al., 1994). Because of its autofluorescence zenz are easily detected in living cells, gels and even living animals.
  • tags that are not to be explained in more detail are the strep tag system (Uhlen et al., 1990) or the myc epitope tag (Pitzurra et al., 1990).
  • fusion proteins which consist of a recombinant protein and a functionally active protein, lies, in addition to the detection described above, in the simplified purification of the expressed fusion proteins.
  • Various systems are known, some of which will be briefly mentioned below.
  • fusion vectors enable the expression of complete genes or gene fragments in fusion with glutathione-S-transferase.
  • the GST fusion protein can easily be purified from the cell lysates by affinity chromatography on glutathione-Sepharose (Smith, Johnson, 1988). Biochemical and immunological detection is available.
  • MBP maltose-binding protein
  • MBP is a periplasmic protein from E. coli, which is involved in the transport of maltose and maltodextrins through the bacterial membrane (Kellermann et al., 1982). It was mainly used for expression and purification of alkaline phosphatase on a cross-linked amylose column.
  • the Intein system is especially suitable for the rapid purification of a target protein.
  • the inteingen has the sequence for the intein-chitin binding domain (CBD), whereby the fusion protein can be bound to a chitin column directly from the cell extract and thus purified (Chong et al., 1997).
  • CBD intein-chitin binding domain
  • Glucose dehydrogenase is a key enzyme during the early phase of spore formation in Bacillus megaterium (Jany et al., 1984). It specifically catalyzes the oxidation of ß-D-glucose to D-gluconolactone, with NAD + and NADP + acting as coenzymes. In addition to bacterial spores, the enzyme is also found in mammalian liver. There are two in B. megaterium M1286 mutually independent glucose dehydrogenase genes (gdh) (Heilmann et al., 1988).
  • GdhA and gdhB differ considerably in their nucleotide sequence, whereas GIcDH-A and GIcDH-B have approximately the same substrate specificity despite different protein sequences. Further information and the corresponding DNA and amino acid sequences are also z.
  • fusion proteins which contain GIcDH or a sequence which have the biological activity of GIcDH are outstandingly suitable for detecting any desired “foreign or target protein” more quickly, simply and thus more efficiently than with the prior art described .
  • This property is based on the surprising finding that GIcDH retains its enzymatic activity under conditions under which other enzymes are inactivated (e.g. in SDS-PAGE).
  • glucose dehydrogenase therefore facilitates purification of the fusion protein in an egg-like state due to its affinity for dyes immobilized on a gel, for example, which are commercially available. step.
  • GIcDH can be detected as a component of a fusion protein by coupling the enzymatic reaction to a sensitive color reaction, preferably with iodophenylnitrophenylphenyltetrazolium salt (INT) or nitroblue tetrazoium salt (NBT) (under the conditions mentioned), as a result of which the indirect detection of the foreign protein is further simplified.
  • the staining method for GIcDH as a marker enzyme also has the advantage that it does not hinder the usual staining of proteins with, for example, Coomassie dyes or silver staining in the same gel.
  • the fusion protein in addition to GIcDH and the foreign protein, additionally consists of a tag peptide, which can be used for additional characterizations of the proteins bound to the tag peptide.
  • the characterization takes place, for example, via the polyhistidine tag, which is recognized as an antigen by specific antibodies.
  • the detection of the resulting antigen-antibody complex is then carried out, for example, with the aid of a peroxidase (POD) -labeled antibody using methods known per se.
  • POD peroxidase
  • the bound peroxidase creates a chemiluminescent product after adding an appropriate substrate (e.g. ECL system, Western Exposure Chemiluminescent Detection System, Amersham), which can be detected with a suitable film.
  • the immunological detection can also be carried out using a special antibody tag, e.g. B. the myc day.
  • a special antibody tag e.g. B. the myc day.
  • the polyhistidine tag alone or in combination with the myc tag, has the additional advantage that the fusion protein can be purified by binding to a metal chelate column.
  • the GIcDH fusion protein can also be linked directly to a specific anti-GIcDH antibody, e.g. was immobilized on a chromatographic gel such as agarose, purified or isolated using affinity chromatography.
  • GIcDH can be expressed in high yield in soluble form, preferably in E. coli using the known expression systems (see above). So was recombinant glucose dehydrogenase from Bacillus megaterium M1286 successfully expanded in E. coli with high enzymatic activity (Heilmann 1988). The expression of other eukaryotic genes in E. coli is often limited by the instability of the polypeptide chain in the bacterial host. Incorrect folding can lead to aggregation ("inclusion bodies"), reduced or missing biological activity and proteolytic degradation.
  • a corresponding fusion gene in which the GIcDH gene or a fragment with biological activity of GIcDH has been ligated to the gene of the desired foreign protein can now be converted into the fusion protein according to the invention with an almost unchanged expression rate and yield compared to the GIcDH gene without a fusion partner .
  • This can also take place if the foreign protein cannot be expressed on its own or only in reduced yields or only in an incorrectly folded state or only using additional techniques.
  • the desired foreign protein can thus be obtained by subsequent cleavage of the marker protein GIcDH or the target protein, for example with endoproteases.
  • tridegin serves as an example of a target protein which can be successfully expressed in E. coli as a fusion protein together with GIcDH.
  • Tridegin is an extremely effective peptide inhibitor for the blood coagulation factor Xllla and comes from the leech Haementeria ghilianii (66 AS, 7.6 kD; Finney et al., 1997).
  • the invention is not limited to the expression of the fusion proteins according to the invention in E. coli. Rather, such proteins can also advantageously be synthesized in mammalian, yeast or insect cells with good expression rates using methods known per se and corresponding stable vector constructions (e.g. using the human cytomegalovirus (CMV) promoter).
  • CMV human cytomegalovirus
  • the invention thus relates to a recombinant fusion protein consisting of at least a first and a second amino acid sequence, the first sequence having the biological activity of glucose dehydrogenase.
  • the invention relates in particular to a corresponding recombinant fusion protein, in which said second sequence is any recombinant protein / polypeptide X or represents parts thereof.
  • the fusion proteins according to the invention can additionally contain recognition sequences, in particular tag sequences.
  • the invention thus also relates to a corresponding fusion protein which can additionally have at least one further recognition sequence or tag sequence suitable for the detection.
  • the fusion proteins according to the invention can be used in various ways.
  • the properties of glucose dehydrogenase play a decisive role here.
  • the invention thus relates to the use of glucose dehydrogenase as a detector protein for any recombinant protein / polypeptide X in one of said fusion proteins.
  • the invention furthermore relates to the use of glucose dehydrogenase in a detection system for the expression of a recombinant protein / polypeptide X as part of a corresponding fusion protein.
  • the invention furthermore relates to the use of GlcDH for the detection of protein-protein interactions, one partner corresponding to the recombinant protein / polypeptide X, as defined above and below.
  • GIcDH can serve as a detector protein for any third protein / polypeptide which is not part of the fusion protein but is able to bind to the second sequence of the protein / polypeptide X of said fusion protein.
  • GIcDH can be used as a marker protein by a partner in ELISA systems, Western blot and related systems. Since it uses recombinant techniques, the invention naturally also includes corresponding vectors, host cells and expression systems.
  • the invention also relates to the use of appropriate expression vectors in optimizing the expression of a recombinant protein / polypeptide X in a recombinant production process and the use of a corresponding host cell in optimizing the expression of a recombinant protein / polypeptide X. in such a manufacturing process.
  • the invention also relates to a method for the rapid detection of any recombinant protein / polypeptide X by means of gel electrophoresis, in particular SDS-PAGE gel electrophoresis, a corresponding fusion protein being produced, separated by means of gel electrophoresis and the recombinant protein / polypeptide to be detected in the gel via the enzyme activity of the Glucose dehydrogenase is made visible.
  • a color reaction based on tetrazolium salts in particular iodophenylnitrophenylphenyltetrazolium salt (INT) or nitroblue tetrazolium salt (NBT), is used to detect the enzyme activity of glucose dehydrogenase, with a color reaction possibly occurring before or after said color reaction general protein staining can follow according to the prior art.
  • tetrazolium salts in particular iodophenylnitrophenylphenyltetrazolium salt (INT) or nitroblue tetrazolium salt (NBT)
  • Fig. 1 Construction scheme of the vector pAW2.
  • the vector contains the
  • Fig. 2 Construction scheme of the vector pAW3.
  • Fig. 3 Construction scheme of the vector pAW4.
  • the vector contains the
  • GIcDH Sequence for GIcDH and tridegin. The full sequence is in Seq. Id. No. 3 shown.
  • Fig. 4 Staining GIcDH on an SDS-PAA gel. The dyeing method is described in more detail in the examples. 1_: rainbow marker; 2: 0.1 ⁇ g GIcDH; 3: 0.05 ⁇ g GIcDH; 4: 0.001 ⁇ g GIcDH; 5: Lysate HC11 cells; 6: Prestained SDS marker.
  • Fig. 5 Detection of the expressed GIcDH enzyme (15% SDS-PAA gel,
  • Fig. 6 Dilution series from pAW2 expression (15% SDS-PAA gel, INT-
  • 1_ rainbow marker
  • 2 10 ul cell extract / 100 ul suspension
  • 3 10 ul cell extract / 1: 5 dilution
  • 4 10 ⁇ l cell extract / 1:10 dilution
  • 5 10 ul cell extract / 1:20 dilution
  • 6 0.5 ⁇ g GIcDH
  • 7 broad-range SDS marker
  • 8 Prestained SDS marker
  • Cell extract volume 100 ⁇ l.
  • Fig. 7 Detection of the expressed tridegin / GIcDH fusion protein (10%
  • Fig. 8 Immunodetection of tridegin / His- and tridegin / His / GIcDH-
  • Fusion protein (from 10% SDS-PAA gel, ECL detection) and comparison with Trideegin / His / GIcDH (10% SDS-PAA gel, INT-CBB staining); 1: broad range marker; 2: 1 ml cell extract (pAW2 expression); 3: 100 ⁇ l cell extract (pST106-
  • Fig. 9 SDS gel, which illustrates the sensitivity of the detection of GIcDH. 1, 5, 10, 25, 50 ng GIcDH and molecular weight markers are shown (left column).
  • GIcDH glucose dehydrogenase protein
  • gdh glucose dehydrogenase gene
  • NAD Nicotinamide adenine dinucleotide (phosphate), free acid Od x optical density at x nm ompA outer membrane protein A ori origin of replication
  • RNAse ribonuclease rpm revolutions per minute rRNA ribosomal RNA
  • the methods and techniques used in this invention are well known and described in the relevant literature.
  • the disclosure content of the above-mentioned publications and patent applications especially by Sambrook et al. and Harlow & Lane and EP-B-0290 768 according to the invention.
  • the plasmids and host cells used according to the invention are generally exemplary and can in principle be replaced by modified or differently constructed vector constructions or other host cells, provided that they still have the constituents essential to the invention.
  • the production of such vector constructions as well as the transfection of corresponding host cells and the expression and purification of the desired proteins largely correspond to known standard techniques and can also be modified within a wide range according to the invention.
  • the Bacillus megaterium GIcDH structural gene was modified by means of PCR, the plasmid pJH115 (EP 0290 768) acting as a template.
  • the amplified fragment (0.8 kb) which had a Pstl and an Eco47lll recognition sequence at one end, was digested with these enzymes and cloned in the cytoplasmic (pRG45) or periplasmic (pST84) E. coli expression vector ( Fig1, 2).
  • the resulting plasmids, pAW2 and pAW3 now had a GIcDH gene that encodes a protein of approximately 30 kD (261 AS) and is below the strong Tet promoter.
  • the cytoplasmic pAW2 expression vector has a size of approx. 4 kb.
  • the periplasmic pAW3 secretion vector is slightly larger and differs from pAW2 only in one omp A- upstream of the multiple cloning site (MCS).
  • Both vectors also have an MCS with 12 different restriction sites, which in frame cloning with the subsequent enable his day.
  • the polyhistidine (6His) Taq makes it possible to purify the recombinant protein on a metal affinity column.
  • the vector pAW4 finally contains the tridegin gene and the GIcDH gene, which were linked to one another via an MCS, and the polyhistidine (6 His) tag, which is ligated downstream with the GIcDH gene.
  • the individual constructions are shown in Figs. 1, 2 and 3.
  • the selected plasmid constructions are only exemplary and do not limit the invention. They can be replaced by other suitable constructions which contain the DNA sequences mentioned.
  • the preparation of the vectors, the clones and the expression of the proteins is further specified in the examples.
  • the activity staining sensitivity was carried out in the reduced SDS gel for native GlcDH.
  • the SDS gel shown in Fig. 3 was obtained.
  • the GIcDH could be detected up to a concentration of 50 ng.
  • the negative control in which there is no GIcDH, shows no band as expected.
  • Cell extract can be used directly in SDS-PAGE (1 h) l
  • the plasmid pAW2 / clone 9 (pAW2 / K9) was transformed into the competent E. coli expression strain W3110 and two clones from the obtained transformation plate were used to inoculate a 5 ml preculture.
  • the anhydrotetracycline induction took place 2 hours after the inoculation of the main culture.
  • the entire expression lasted 5 h and was terminated at an OD value of 1.65 for clone 1 and 1.63 for clone 2.
  • a strong GleDH band (approx. 35 kD) from 1 ml cell suspension could be detected per clone.
  • the Haemente ⁇ a g an / VTridegin structural gene with coupled His tag was modified by PCR, the plasmid pST106 acting as a template.
  • the resulting plasmid pAW4 now had a tridegin-His-GlcDH fusion protein gene which codes for a protein of approximately 44 kD and is below the strong Tet promoter.
  • the sensitivity and specificity of the GIcDH fusion protein detection enable a quick and easy screening of recombinant foreign proteins.
  • the sensitivity of the GIcDH detection system was determined using native GIcDH.
  • the proof of activity of the native GIcDH showed a red-violet colored band at approx. 30-35 kD in the SDS-PAA gel.
  • the cytoplasmic expression in the E. coli strain W3110 of the recombinant GIcDH from pAW2 gave the same molecular weight.
  • the sensitivity comparison of the native GIcDH to the recombinant GIcDH could be done by comparing the band intensities.
  • the developed test system (see examples) also offers the possibility of double staining of the SDS gels.
  • the specific detection of the GIcDH bands takes place.
  • a conventional protein staining e.g. B. Coomassie staining of the remaining proteins take place.
  • the GIcDH Under reducing conditions in the presence of SDS, the GIcDH surprisingly maintains its full activity in accordance with the invention, which enables rapid detection in the SDS gel.
  • GIcDH activity detection it is also possible to increase the sensitivity of the GIcDH activity detection by using nitroblue tetrazolium salt (NBT) as a substrate for the GIcDH.
  • NBT nitroblue tetrazolium salt
  • the reaction rate of GIcDH detection using INT can, however, be further increased by using Triton X-100 (1% final solution) or adding NaCl (1 M final solution).
  • the recombinant fusion proteins Tridegin / His and Tridegin / His / GleDH were obtained by expression of the pST106 and pAW4 plasmids (Fig. 1, 2). After cell disruption of the respective expression batch, the samples were separated in the SDS-PAGE and transferred to a membrane.
  • the tridegin-His-GIcDH fusion protein was able to be immunologically immunized via its His tag by using an anti- RGS * His antibody in a Western blot.
  • the anti- RGS 'His antibody was able to detect a band at approx. 37 kD and another band at approx. 43 kD for the recombinant tridegin / His / GIcDH fusion protein (Fig. 6).
  • a comparison of the band sizes obtained with the bands obtained after activity staining in the SDS gel shows that the 43 kD band is the tride- gin-His-GIcDH fusion protein and the 37 kD band is the His-GIcDH degradation product of the entire fusion protein.
  • the calin / His tag protein resulted in a band of approximately 26 kD.
  • the somewhat smaller recombinant tridegin / His tag protein resulted in a band with approximately 23 kD, as well as further bands which indicate a binding of the His antibody to other expressed proteins.
  • the immunological detection with the anti- RGS 'His antibody thus proves that the protein detected at 43 kD and the protein at 37 kD contained a His tag.
  • this protein size corresponded approximately to the theoretical size (36.5 kD) of the GIcDH protein with coupled His tag.
  • the biological activity of the tridegin as part of the tridegin-GIcDH fusion protein was examined. This test is based on the inhibition of factor Xllla by native glandular homogenate from leeches or purified tridegin (Finney et al., 1997). The modified test is described in the examples. As a control, the corresponding fusion protein was expressed from pST106 and the GIcDH protein from pAW2.
  • the GIcDH fusion system according to the invention is shown in E. coli as shown in Table 2.
  • the N-terminal fusion protein can be cleaved from the C-terminal target or foreign protein (Collins-Racie et al., 1995).
  • a very great advantage of the GlcDH detection system according to the invention is the fact that no antibodies or other materials such as membranes, blot apparatus, development, etc. machine with films, microtiter plates, titer plate reader, etc. are required. This makes the detection of recombinant fusion proteins with the GIcDH system much cheaper and faster.
  • the corresponding size of the fusion protein can also be determined directly in the SDS-PAA gel without transfer to a membrane. If the activity of the GIcDH is detectable in the fusion protein, the fusion partner should generally also be functionally active. GIcDH does not disturb the folding of the fusion partner.
  • Table 3 an efficient method for obtaining and detecting a fusion protein obtained in E. coli was selected from the literature, which shows the advantages of the GIcDH fusion protein system according to the invention in a comparison.
  • the GIcDH fusion protein system according to the invention is also particularly suitable for increasing the solubility of proteins which are formed as inclusion bodies, particularly in E. coli, and which therefore make subsequent protein purification difficult and expensive. Normally, proteins that have been created as inclusion bodies have to be converted into their native state by complex processes. This does not apply when using the fusion proteins according to the invention.
  • Sensitive GIcDH-specific enzymatic color test • Sensitivity up to at least 50 ng
  • Example 1 The following examples further illustrate the invention without restricting it.
  • Example 1 Example 1 :
  • the above oligonucleotides were used (Tab. 4) -
  • the following table 5 gives an overview of the microorganisms used. All microorganisms are derived from E. coli K12 and belong to risk group 1.
  • Donor organism Expression strain M 7037 (E. coli N 4830 / pJH 115) v. 10/21/96 (Merck).
  • pJH 115 pUC derivative, 5.9 kb, 0 P L promoter, gdh, to (terminator), galk (galactosidase gene), bla (ß-lactamase gene), oh (origin of replication), 2 Hindill, 2 BamHI and one EcoRI and one Clal interface.
  • Transformation of plasmids into competent E. coli cells SOC medium: 20 g Bacto-Trypton, 5 g Bacto-Yeast extract, 0.5 g NaCI, 0.2 g KCI ad 1 l H 2 O b i d. , autoclave. Before use, add 0.5 ml 1 M MgCl 2/1 M MgS0 4 (sterilized), 1 ml of 1 M glucose (sterile-filtered) LB (Amp) agar plates: combine 1 l LB medium (without ampicillin), 15 g agar agar, autoclave, cool to approx. 60 ° C and 1 ml ampicillin solution (100 mg / ml). Execution:
  • TOPO-TA-Cloning ® is a five-minute cloning process for PCR products amplified with Taq polymerase.
  • the TOPO-TA-Cloning ® kit (version C) from Invitrogen was developed for the direct cloning of PCR products.
  • the system uses the property of thermostable polymerases, which attach a single deoxyadenosine to the 3 'end of all duplex molecules in a PCR (3' A overhang). With the help of these 3'-A overhangs, the PCR products can be linked directly with a vector which has 3'-T overhangs.
  • the kit supplies the specially developed pCR ® 2.1 TOPO vector.
  • the 3.9 kb vector has an / acZ gene for blue / white selection, ampicillin and kanamycin resistance genes.
  • the cloning site is flanked on both sides by a unique EcoRI interface. Ligation approach:
  • the plasmid is isolated from successfully sequenced clones and transformed into the expression strain W3110
  • a clone is picked from the transformation plate and a 5 ml pre-culture is prepared with it. • Spread out the pre-culture on an LB (Amp) plate and inoculate later expressions with clones of this plate • With 1 ml of the pre-culture, the 50 ml main culture is inoculated (ratio 1:50) and the OD 60 o value is determined (reference measurement with unvaccinated LB (Amp) medium)
  • the glucose dehydrogenase band can be specifically detected in the SDS gel with the aid of iodophenylnitrophenyiphenyltetrazolium chloride (INT). This is only possible because the SDS treatment does not destroy the activity of the GIcDH.
  • the GIcDH is detected using a color reaction. The hydrogen formed in the reaction is transferred to the tetrazolium salt INT, producing a violet formazan. Phenanzin methosulfate serves as an electron carrier.
  • Reaction buffer (0.08% INT, 0.005% phenanzin methosulfate, 0.065% NAD, 5% Glc in 0.1 M Tris / HCl (pH 7.5)
  • Proteins that are linked to a His tag are detected indirectly with two antibodies.
  • the anti- RGS 'His Antibody QIAGEN
  • QIAGEN The anti- RGS 'His Antibody
  • the detection of the resulting antigen-antibody complex is then carried out using the Peroxidase (POD) -labeled AffiniPure Goat Anti-Mouse IgG (H + L) antibody.
  • POD Peroxidase
  • the bound peroxidase creates a chemiluminescent product after adding the ECL-substrate mixture, which can be detected with a high-performance chemiluminescence film.
  • Ponceau S solution (0.5% Ponceau S, 7.5% TCA) 1.25 g Ponceau S 18.75 g TCA to 250 ml bidist. Fill up with water. 10x PBS buffer pH 7.4
  • the buffer is used in the 1x concentration.
  • POD-labeled AK 1: 1000 diluted in PBS / 5% skimmed milk powder (new tube) incubate at 37 ° C for 1 h
  • Tridegin detection by inhibition of factor Xllla (method according to Finney et al., 1997, modified according to the invention):
  • synthetic amines are also incorporated into suitable protein substrates. These synthetic amines have intramolecular markers that enable detection.
  • the amine incorporation test is a solid phase test. The titer plates are coated with casein.
  • the substrate biotinamidopentyiamine is incorporated into this casein by factor Xllla.
  • the casein-biotinamidopentylamine product can be produced by the fusion protein streptavidin-alkaline phosphatase (Strep / AP) be detected. This "sandwich” can be done by detecting the phosphatase activity using p-nitrophenyl phosphate. The following reaction takes place:
  • the formation of the 4-nitrophenolate is determined photometrically at 405 nm and is directly proportional to the AP activity. Due to the high affinity of biotin and streptavidin, the phosphatase activity is also proportional to the factor Xllla activity, ie the stronger the absorption (yellowing) the greater the factor Xllla activity (Janowski, 1997).
  • EDTA is a non-specific inhibitor for factor Xllla, whose cofactor Ca 2+ is bound by EDTA in a chelate complex. For this reason, the protein samples used must not contain EDTA and have been pretreated with an EDTA-free protease inhibitor cocktail (Boehringer). Wash buffer: 100 mM Tris / HCl, pH 8.5
  • Solution A Dissolve 0.5% skimmed milk powder in washing buffer
  • Solution B 0.5 mM biotinamidopentylamine, 10 mM DTT, 5 mM CaCl 2 in
  • Solution C Dissolve 200 mM EDTA in washing buffer Solution D Dissolve 1.7 ⁇ g / ml streptavidin-alkaline phosphatase in solution A.
  • Solution F Dissolve 1 mg / ml p-nitrophenyl phosphate, 5 mM MgCl 2 in washing buffer Coating:
  • Pre-incubation buffer 0.1 M Tris / HCl, pH 7.5 0.5 M NaCl

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EP00903672A 1999-02-19 2000-02-08 Glucose-dehydrogenase-fusionsproteine und ihre verwendung in expressionssystemen Withdrawn EP1155130A2 (de)

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DE19906920 1999-02-19
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AR (1) AR022630A1 (pt)
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ATE390481T1 (de) * 2001-12-21 2008-04-15 Curacyte Ag Modifizierte tridegine, ihre herstellung und verwendung als transglutaminase-inhibitoren
CA2535147A1 (en) 2003-08-11 2005-05-19 Codexis, Inc. Improved glucose dehydrogenase polypeptides and related polynucleotides
CN101421396B (zh) * 2006-04-13 2016-01-20 霍夫曼-拉罗奇有限公司 吡咯并喹啉醌依赖性可溶性葡萄糖脱氢酶的改良突变体
CN110894504A (zh) * 2019-12-20 2020-03-20 武汉茵慕生物科技有限公司 强化表达葡萄糖6-磷酸脱氢酶的地衣芽胞杆菌在异源蛋白生产中的应用

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JPS60141299A (ja) * 1983-12-28 1985-07-26 Wako Pure Chem Ind Ltd 脱水素酵素の活性度測定法
JPS63230098A (ja) * 1987-03-18 1988-09-26 Fujitsu Ltd 酵素の分析方法
DE3711881A1 (de) * 1987-04-08 1988-10-27 Merck Patent Gmbh Verfahren zur herstellung von glucosedehydrogenase aus bacillus megaterium
AU4032997A (en) * 1997-02-07 1998-08-26 Kaneka Corporation Novel carbonyl reductase, gene that encodes the same, and method of utilizing these
US6399859B1 (en) * 1997-12-10 2002-06-04 Pioneer Hi-Bred International, Inc. Plant uridine diphosphate-glucose dehydrogenase genes, proteins, and uses thereof

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AU771320B2 (en) 2004-03-18
CN1340104A (zh) 2002-03-13
CZ20012739A3 (cs) 2001-11-14
HUP0200285A2 (hu) 2002-05-29
ZA200107686B (en) 2002-12-18
JP2002538782A (ja) 2002-11-19
NO20014011L (no) 2001-10-02
AR022630A1 (es) 2002-09-04
PL350574A1 (en) 2002-12-30
NO20014011D0 (no) 2001-08-17
AU2546800A (en) 2000-09-04
CA2368461A1 (en) 2000-08-24
BR0008370A (pt) 2001-11-06
US20050112744A1 (en) 2005-05-26
KR20010103017A (ko) 2001-11-17
WO2000049039A2 (de) 2000-08-24
SK11742001A3 (sk) 2002-03-05

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