WO2005003155A1 - ブロッキング効率の向上したタンパク質 - Google Patents
ブロッキング効率の向上したタンパク質 Download PDFInfo
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- WO2005003155A1 WO2005003155A1 PCT/JP2004/009785 JP2004009785W WO2005003155A1 WO 2005003155 A1 WO2005003155 A1 WO 2005003155A1 JP 2004009785 W JP2004009785 W JP 2004009785W WO 2005003155 A1 WO2005003155 A1 WO 2005003155A1
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- protein
- blocking
- amino acid
- acid sequence
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07K—PEPTIDES
- C07K14/00—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
- C07K14/195—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from bacteria
- C07K14/24—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from bacteria from Enterobacteriaceae (F), e.g. Citrobacter, Serratia, Proteus, Providencia, Morganella, Yersinia
- C07K14/245—Escherichia (G)
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
- G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
- G01N33/53—Immunoassay; Biospecific binding assay; Materials therefor
- G01N33/543—Immunoassay; Biospecific binding assay; Materials therefor with an insoluble carrier for immobilising immunochemicals
- G01N33/54393—Improving reaction conditions or stability, e.g. by coating or irradiation of surface, by reduction of non-specific binding, by promotion of specific binding
Definitions
- the present invention relates to a method for screening a novel blocking protein or partial sequence protein candidate having a blocking ability based on amino acid sequence information. Furthermore, the present invention provides a method for screening a protein by modifying the amino acid sequence of protein. For proteins with improved locking efficiency. Furthermore, the present invention relates to a blocking reagent, a stabilizing agent, an excipient, a folding auxiliary agent, a refolding auxiliary agent, and a medical coating agent containing the protein. INDUSTRIAL APPLICABILITY The present invention can improve the blocking efficiency of a protein that can be highly expressed in Escherichia coli, and is useful when a large amount of a protein having excellent blocking efficiency is recombinantly produced. Background art
- proteins directly extracted from biological components have been often used as blocking agents used in immunoassays and the like.
- albumin-casein derived from seafood there is a history of the widespread use of albumin-casein derived from seafood.
- various restrictions have been added due to problems such as mad cow disease.
- methods for producing them using recombinants have the advantage of eliminating pathogens (substances), but few of them have been put into practical use due to problems such as productivity.
- FIG. 1 is a diagram showing the concept of measuring the blocking efficiency.
- FIG. 2 is a diagram showing a protein splitting method.
- FIG. 3 is a diagram showing a blocking mechanism of a protein exhibiting a blocking ability.
- FIG. 4 is a diagram showing a three-dimensional structure of DnaK384-607. The ⁇ -sheet corresponds to the ⁇ -terminal, and the helix corresponds to the C-terminal.
- FIG. 5 is a diagram showing the blocking efficiencies of various Dna ⁇ mutants.
- Figure 5 is a diagram showing the blocking efficiencies of various Dna ⁇ mutants.
- FIG. 6 is a diagram showing the structure of the Escherichia coli DnaII protein and the structure of the created mutant.
- FIG. 7 is a diagram showing the three-dimensional structure of DnaK 381-553.
- FIG. 8 is a diagram showing a blocking mechanism of a protein having a modified hydrophobic domain.
- FIG. 9 is a diagram showing the blocking efficiencies of various Dna K mutants.
- VAV 384-607
- Dn aK384-607 D479 V, D48 IV
- FIG. 10 is a diagram showing the correlation between the DnaK mutant concentration and the blocking effect.
- FIG. 11 is a view showing the blocking rate of the DnaK mutant.
- FIG. 12 is a diagram showing the application of a DnaK mutant to ELISA blocking.
- Figure 13 shows the content of hydrophilic and hydrophobic amino acids in proteins frequently used for blocking and proteins with high hydrophobicity.
- FIG. 14 shows the characteristics of the amino acids contained at the N-terminal side and C-terminal side of BSA, o; casein, lipase, and DnaK384-607.
- I11 indicates the absolute value of the difference between the hydrophilic and hydrophobic ratios at the N-terminal side and the C-terminal side.
- FIG. 15 shows a comparison of the blocking effect of the DnaK fragment without the histidine tag (native).
- BSA (fraction V) was adjusted to a concentration of 0.5 mg / ml for lOmgZml, natiovDnaK419-607 fragment, and this is shown as a comparison at higher concentrations.
- concentration of BSA (fraction V) was adjusted to 2 mg / m 1, and the value of the naive Dna K419-607 fragment was adjusted to 0.1 mg / m 1, and this is shown as a comparison at a low concentration.
- FIG. 16 illustrates the data at the high concentration of FIG.
- FIG. 17 illustrates the data at the low concentration of FIG. Disclosure of the invention
- An object of the present invention is to provide a method for easily finding a protein having a blocking ability from an amino acid sequence, and a protein which can be expressed in large amounts in Escherichia coli or the like and has improved blocking efficiency by amino acid sequence modification. To provide.
- the present invention has the following configurations.
- a method for screening a novel blocking protein or partial sequence protein candidate having a blocking ability based on amino acid sequence information comprising screening a protein or partial sequence protein that satisfies the following conditions: How to screen
- A The amino acid sequence of the protein is divided into two, and each hydrophilic amino acid (D, E, K, H, R, Y) and hydrophobic amino acid (G, A, V, L, I, ⁇ , F, W,
- D, E, K, H, R, Y hydrophilic amino acid
- G, A, V, L, I, ⁇ , F, W hydrophobic amino acid
- the absolute value of the difference between the hydrophilicity / hydrophobicity at each of the two parts calculated from the content of ⁇ ) using the following formula is 0.1 or more
- the hydrophilic part (the higher value of the hydrophilic Z hydrophobicity) is 0.5 or more
- a novel blocking protein or partial-sequence protein having blocking ability screened by the method of (1) which can be obtained by the following analysis step D; Protein or partial sequence protein that satisfies the conditions of D 1.
- Candidate proteins that satisfy the conditions of claim 1 0.5 to lmg / m1: 2 OmM Tr is — Adding HC 1 (diluted to pH 7.0) and similarly prepared serum albumin (Fraction V), blocking at 2 ° C to 10 ° C for 4 to 5 hours, and discarding the solution;
- Peroxidase for labeling from horseradish was used as a candidate protein solution (0.5- lmg / m 1: diluted in PBS (1)) and dissolved in serum serum albumin (Fraction V) prepared in the same manner to obtain 0.05 mg / m 1;
- the value measured in the candidate protein is less than 2.5 times the color development of serum albumin.
- a novel blocking protein or partial sequence protein having blocking ability screened by the method of (1) which can be obtained by the following analysis step H and satisfies the following condition I Protein or partial sequence protein:
- the measured value of the candidate protein is less than 2.5 times that of the serum of albumin.
- the amino acid sequence modification is characterized by amino acid substitution, removal, or insertion.
- a protein having improved blocking efficiency which is derived from “HSP70 family protein”.
- the protein having improved blocking efficiency according to (8) which is a protein obtained by removing a part of the amino acid sequence of Dna K protein.
- the protein having an improved blocking efficiency according to item 1.
- the protein having improved blocking efficiency according to (8) comprising the amino acid sequence at positions 384 to 607 of the DnaK protein, wherein the aspartic acid having amino acid numbers 479 and 481 has been substituted with valine.
- a blocking protein having one or more hydrophilic domains and one or more hydrophobic domains, wherein the hydrophobic domain can be adsorbed on the vessel wall and the hydrophilic domain is a vessel.
- a blocking protein capable of covering a hydrophobic domain adsorbed on a wall.
- MBP maltose binding protein
- GST daltathione S-transferase
- F1ag tag F1ag tag
- My c tag F1ag tag
- evening dematurity tag The protein according to (20), which is selected from a tag.
- (22) A method for producing a protein, comprising producing the protein according to any one of (2) to (21) using a prokaryote
- a method for producing a protein comprising producing the protein according to any one of (2) to (21) using Escherichia coli.
- a method for producing a protein which comprises producing the protein according to any one of (2) to (21) using a cell-free protein synthesis method
- the term blocking refers to the prevention of nonspecific adsorption of components to containers, carriers, etc. In particular, preventing non-specific adsorption of proteins to resins such as plastics.
- non-specific adsorption of a component of a measurement control to a vessel wall interferes with the measurement as a background.
- the adsorption of the antibody to the polystyrene plate is remarkable, and usually, a protein that easily adsorbs to a resin or the like is added in advance to prevent the non-specific adsorption of the antibody, that is, to perform blocking. That is widely done.
- immunological measurement is mainly considered, and by measuring non-specific adsorption of IgG in human serum, which is known as an example in which non-specific adsorption is most remarkable, to a polystyrene plate, The blocking effect was measured. That is, the measurement includes the following steps.
- a lipase derived from Pseudomon as aeruginosa which is known to have a high content of hydrophobic amino acids, for the purpose of examining whether or not highly hydrophobic protein has blocking ability.
- Lipases are also used in clinical testing applications, etc. It is known that the ability to adsorb to plastic surfaces is so high that it can be problematic. However, as a result of the experiment, it became clear that the blocking effect was hardly observed.
- the ratio of hydrophilic amino acids to hydrophobic amino acids in each protein is shown in Fig. 13, and a comparison shows that the hydrophobicity of BSA and casein is lower than that of lipase.
- hydrophilic amino acid and the hydrophobic amino acid referred to herein have various definitions depending on textbooks and the like, but in the present invention, the hydrophilic amino acids are aspartic acid, glutamic acid, lysine, histidine, arginine, and tyrosine.
- the hydrophobic amino acids were defined as glycine, alanine, valine, leucine, isoleucine, methionine, phenylalanine, triptophan, and proline.
- hydrophilic amino acids are defined as aspartic acid, glutamic acid, lysine, histidine, arginine, and tyrosine.
- the hydrophobic amino acids are defined as dalysin, malanine, valine, leucine, isoleucine, methionine, fenylalanine, tributofan, and proline.
- Hydrophilic amino acids, His, Tyr, and particularly G 1 y, A 1 a, especially G 1 y are considered to be low hydrophobicity in hydrophobic amino acids, and T yr and G 1 y are excluded for more precise prediction. More preferably, a good result may be obtained if the calculation is performed excluding His, Tyr, Gly, and Ala.
- the number at the C-terminal side is 0.83, indicating that there is a difference of 0.17.
- the difference was 0.84 on the N-terminal side and 0.64 on the C-terminal side, and the difference was 0.24.
- the N-terminal side is 0.39 and the C-terminal side is 0.44, which is 0.05 and the difference is less than 0.1.
- a condition that a hydrophilic region was required in addition to a relatively hydrophobic region in the protein molecule in order to exhibit the blocking ability.
- the hydrophilic portion, the hydrophobic portion and the full-length hydrophilic / hydrophobic ratio are preferably in the following ranges.
- the hydrophilic portion has a hydrophilic Z hydrophobicity of 0.5 to 2.0, more preferably 0.7 to 1.7, and further preferably 0.8 to 1.5.
- the hydrophilic portion has a hydrophilic Z hydrophobicity of 0.2 to 1.1, more preferably 0.3 to 1.0, and even more preferably 0.4 to 0.9.
- the hydrophilic / hydrophobic ratio of the whole protein is 0.4 to 2.0, more preferably 0.5 to 1.5, and still more preferably 0.6 to 1.0.
- the difference (absolute value) of the hydrophilic Z hydrophobicity between the hydrophilic part and the hydrophobic part is preferably 0.1 to 0.6, more preferably 0.15 to 0.5, and still more preferably 0.15 to 0. 4
- the hydrophilic portion and the hydrophobic portion may each be a bisected portion, for example, the C-terminal side (or the N-terminal side).
- the present invention assumes that the hydrophilic portion and the hydrophobic portion are present in each of two parts, for example, at the C-terminal side or the N-terminal side.
- the addition of a sequence that is neither hydrophobic nor hydrophobic is included in the present invention as long as the hydrophilic portion and the hydrophobic portion are present.
- the present invention provides a hydrophilic part-hydrophobic part-hydrophilic part, a hydrophobic part-hydrophilic part-hydrophobic part, and a hydrophilic part-hydrophobic part-hydrophilic part-hydrophilic part. What has each part in order like a hydrophobic part is also contained in this invention.
- the hydrophobic part (hydrophobic domain) is adsorbed on the vessel wall, and the hydrophilic part (hydrophilic domain) is overlaid on the vessel wall. It can be inferred that locking is performed.
- Figure 3 shows the model. Lipase does not show blocking ability because it is adsorbed but the adsorbed protein It is expected that further non-specific adsorption to the protein would have occurred because the quality was too hydrophobic.
- the ratio of the hydrophobic part adsorbing to the vessel wall and the hydrophilic part covering the hydrophobic part is the hydrophobic part
- the hydrophilic portion it is 0.3 to 10, preferably 0.5 to 5, and more preferably 0.7 to 2, the hydrophilic portion relative to 1. If the hydrophobic part is too large, it cannot be covered with the hydrophilic part, and other proteins will be further adsorbed on the hydrophobic part adsorbed on the vessel wall. On the other hand, if the hydrophilic portion is too large, the area where the hydrophobic portion is adsorbed on the vessel wall becomes too small, so that it cannot be sufficiently firmly adsorbed or the efficiency of blocking decreases.
- “dividing into two” does not mean that the entire sequence is divided by about 50%, but merely that it is divided into a hydrophobic part and a hydrophilic part.
- the hydrophilic / hydrophobic ratio of the plural hydrophilic parts and hydrophobic parts is calculated as an average value.
- the hydrophilic portion and the hydrophobic portion each have a lump portion, preferably having a domain structure, and each portion has at least 20%, preferably at least 30%, more preferably at least 40% of the entire sequence. % Or more.
- it is preferable and effective to analyze the amino acid sequence by dividing the amino acid sequence into N-terminal side and C-terminal side.
- the difference between the hydrophilic domain and the hydrophobic domain in the hydrophilic Z hydrophobicity varies among the proteins, and only the magnitude of the value reflects the blocking ability in detail. It may not be possible. One of the factors seems to be molecular weight.
- "consisting of more than 100 amino acids” means that the total number of amino acids in the entire amino acid sequence is at least 100 residues, preferably 150 residues. Consisting of more amino acids, more preferably more than 200 residues of amino acids. The upper limit is preferably 2000 amino acid residues, more preferably 1500 amino acid residues, and still more preferably 10000 amino acid residues.
- the number of amino acids in the hydrophilic portion or domain is preferably at least 30 amino acid residues, more preferably at least 50 amino acid residues, even more preferably at least 60 amino acid residues, particularly preferably at least 80 amino acid residues. It is preferably 100 amino acid residues or less, more preferably 500 amino acid residues or less.
- the number of amino acids in the hydrophobic portion or domain is preferably at least 30 amino acid residues, more preferably at least 50 amino acid residues, still more preferably at least 60 amino acid residues, particularly preferably at least 80 amino acid residues, and It is preferably at most 1,000 amino acid residues, more preferably at most 500 amino acid residues.
- the domain as referred to herein means a region having one unit in the structure or function of a molecule.
- the domain mainly means a unit having a structural unit.
- DnaK384-607 various deletion mutants of DnaK384-607 were prepared, and it was examined which structure of DnaK plays an important role in blocking.
- the mutants examined this time are shown in FIG.
- the five proteins examined were DnaK 384-638, DnaK 384-607, DnaK 384-578, DnaK 384-561, DnaK 508-607, and DnaK 525-607. These proteins can be expressed in large quantities using Escherichia coli as a host, and expressed by adding a histidine fragment to the N-terminal side of each protein, then easily purified using a nickel chelate column, and used in experiments. be able to.
- the blocking ability is impaired due to the shrinkage of the hydrophilic portion of the protein having the blocking ability or the disruption of the structure.
- the hydrophilic portion alone does not exhibit blocking ability.
- the hydrophilic part is important in addition to the hydrophobic part in order to exert the blocking ability, and the protein showing the blocking ability is adsorbed on the plate by the hydrophobic part as shown in Fig. 3, and the hydrophilic part is It is considered that the blocking effect can be considered as a result of covering the plate surface with the part.
- DnaK it is expected to be exactly as shown in the left diagram of FIG. In general, it is known that the secondary structure collapses due to denaturation or mutation, thereby losing the hydrophilicity of the protein. Thus, it is expected that preparing a partial sequence protein is not appropriate. On the contrary, it seems that it is possible to improve hydrophobicity by disrupting the hydrophobic domain as shown in FIG.
- the domains are important, and it appears that at least one more domain structure is required. Therefore, 100 amino acids required to construct one structural domain can be used as a guide. Therefore, it can be said that the present invention desirably comprises at least more than 100 amino acids, that is, has more than one domain structure.
- the present invention provides a method for screening a novel blocking protein or partial sequence protein having a blocking ability based on amino acid sequence information. Specifically, it is a method of screening for a protein or partial sequence protein that satisfies the following conditions.
- the hydrophilic part (higher value of hydrophilicity / hydrophobicity) is 0.5 or more
- D is aspartic acid
- E glutamic acid
- K is lysine
- H is histidine
- R is arginine
- Y is tyrosine
- G is glycine
- A is alanine
- V is valine
- L is leucine
- I is isoleucine
- M indicates methionine
- F indicates phenylalanine
- W indicates tributophan
- P indicates proline.
- partial sequence protein refers to a protein consisting of a partial amino acid sequence of a wild type protein, and is preferably a protein having more than one domain structure.
- the amino acid sequence When the amino acid sequence is divided into, for example, the N-terminal side and the C-terminal side, it is not always necessary to divide exactly, but it is preferable to divide the amino acid sequence so that the numbers of both amino acids are almost equal. If a signal peptide is expected from the amino acid sequence, it is advisable to exclude that part. Actually, in the present invention, the calculation was performed using the mature amino acid sequence from which the signal peptide was removed for both BSA, ⁇ casein and lipase. In addition, a dividing method other than bisecting the ⁇ terminal side and the C terminal side as shown in FIG. 2 is also preferably used. In such a case, a protein whose tertiary structure is known or a protein whose tertiary structure is predicted can be preferably applied.
- the present invention also relates to a protein or partial sequence protein having blocking ability, which is screened from an amino acid sequence by the above method, and which satisfies the condition of E in the following analysis step D. .
- Candidate protein that satisfies the conditions of claim 1 (diluted in 50-: L0 Omg / m1: 2 OmM Tris_HC1 (pH 7.0)) in each well of a polystyrene imino plate. And adding serum serum albumin (Fraction V) prepared in the same manner, blocking at 2 ° C to 10 ° C for 4 to 5 hours, and discarding the solution.
- Fraction V serum serum albumin
- Color development of the candidate protein is 2.5 times or less, preferably 2 times or less, more preferably 1.5 times or less, still more preferably 1.2 times or less, and especially 1 time of the color development of bovine serum albumin It is as follows.
- the blocking ability is measured based on the non-specific adsorption of IgG in human serum, which is known to have remarkable non-specific adsorption on a plastic plate.
- the polystyrene immunonotiter plate (96-well type) used here is a polystyrene 96-well immunonotiter plate generally used for immunoassay.
- the candidate protein is purified by an appropriate method and diluted with 2 OmMTris_HCl (pH 7.0) to a final concentration of 50 to 50 mg / ml.
- BSA serum albumin
- BSA FractiOnV commercially available from SIGMA or the like can be used.
- the performance is the same, it is not particularly required to be F ractio n V. After blocking for 4-5 hours at 2-8 ° C, completely remove the solution and proceed to the next step without washing.
- the human serum used here is not particularly limited as long as it is a serum separated from a normal adult. Since the stock solution has a high concentration, it is recommended to use a 25 to 50-fold dilution with PBS (-) before use. Since the amount of IgG in the individual varies, the dilution ratio may be slightly changed. Pre Non-specific adsorption to a batch is performed at 37: for 30 minutes. In addition, in order to accurately measure the amount of serum to be added at this time, it is preferable that the amount be smaller than the amount of the liquid that was initially blocked. For example, when blocking was performed at 100/21, 50 1 Add diluted serum solution from.
- washing is preferably performed three times or more, and more preferably four times.
- a dedicated plate washer may be used.
- the enzyme-labeled anti-human IgG antibody is diluted to an appropriate concentration with an appropriate solution, and added to the above-mentioned well.
- Appropriate reaction time is 37 ° C for 1 hour.
- the dilution of the antibody is usually preferably used for immunological detection, and the dilution of the antibody should preferably contain an appropriate blocking agent (BSA or casein), so that the dispersion will be more consistent and more preferably 0. 01M phosphate buffer (pH 7.4), 0.15M NaC 0.5% strength Use zein.
- peroxidase and alkaline phosphatase are preferably used, and particularly, peroxidase is preferably used.
- a coloring reagent for oxidase tetramethylbenzidine (TMBZ: 3, 3 ', 5, 5'-Tetramethy1 benzizidine) is preferably used.
- WT-1 can be used as a chromogenic substrate for alkaline phosphatase. It is desirable that the color development time is such that the absorbance of the target gel does not lose its quantitativeness (0.5 to 1.5). Note that the correct value cannot be obtained if the value exceeds the quantification range. In addition, accurate values cannot be obtained unless the plate is dried as much as possible throughout the entire operation.
- the novel blocking protein or partial sequence protein having the blocking ability of the present invention satisfies the conditions described in claim 1 and shows a value of 2.5 times or less the value of BSA in this assay, that is, It is a protein having blocking ability.
- Example 7 a method as shown in Example 7 can be used. That is, after serially diluting peroxidase in the candidate protein solution, apply it to the solid phase, allow it to adsorb for a certain period of time, and measure non-specific adsorption of peroxidase.
- the as a method for confirming the adsorbed peroxidase a color development method using tetramethylbenzidine (TMBZ: 3,3 ', 5,5'-Tetramethylbenzidine) is preferably used as in the above method. Also in this Atsushi, a value of 2.5 times or less of the BSA value is an index indicating the blocking ability.
- TMBZ tetramethylbenzidine
- a non-specific adsorption may be measured by adding a diluted peroxidase solution to a previously blocked solid phase. Even in this case, a value of 2.5 times or less of the BSA value is an indicator of the blocking ability.
- concentration of the peroxidase solution used here is preferably 0.05 mg / ml, but if adjusted and used so that it can be measured in a common sense range, it will lead to more accurate evaluation.
- the dilution of peroxidase is preferably performed with PBS (-), but is not particularly limited.
- the present invention preferably has more than one domain structure, but especially in the case of a hydrophobic domain, even if a part of one of the two domain structures is missing as in this example. good.
- the number of amino acids of the protein or partial sequence protein of the present invention is 100 or more, preferably 150 or more, and more preferably 180 or more.
- the present invention is a novel protein in which the amino acid sequence of the protein meeting the above-mentioned claim 1 is modified to further improve the blocking efficiency of the protein or its partial sequence protein.
- new as used herein means novel at the level of amino acid modification, and may be a known protein. In the case of a partial sequence, a sequence having a previously unknown partial sequence is also regarded as new.
- the amino acid sequence may be modified by any of amino acid substitution, removal (delivery), insertion (insertion), or overlapping.
- a mutation that further enhances the hydrophobicity of the hydrophobic region or a mutation that further enhances the hydrophilicity of the hydrophilic region is effective and is preferably used.
- the protein to be modified may be of prokaryotic or eukaryotic origin, such as E. coli.
- a prokaryotic protein is preferably used. More preferably, a protein derived from Escherichia coli is used.
- the protein used may be a partial structure such as a domain, but is preferably used.
- a blocking agent is often mixed with an enzyme or the like and used as a stabilizer / excipient in many cases, and it can be said that a protein having no special function of enzyme activity is suitable for the present invention. Further, a protein from which a domain having an enzymatic activity has been removed is also preferably used.
- a protein derived from the HSP70 family protein is preferably used, and more preferably, a protein derived from Escherichia coli DnaK protein is used. Further, preferably, the substrate binding domain of the HSP70 family protein from which the ATPase domain has been removed is used, and more preferably, the substrate binding domain of the DnaK protein from which the ATPase domain of Escherichia coli has been removed is used. Can be The substrate binding domain of the DnaK protein has already been introduced above as an example.
- the proteins belonging to the HSP70 family used in the present invention are not particularly specified, but include Escherichia coli DnaK, Ssa1p present in yeast cytoplasm, Ssc1p present in yeast mitochondria, and yeast endoplasmic reticulum.
- Kar2p HSP70 in the mammalian cytoplasm, Bip in the mammalian endoplasmic reticulum, mHsp70 in the mammalian mitochondria, and constitutive expression regardless of heat shock.
- HSP70 homologues such as HSC70. Many homologs are known in the HSP70 family, some of which are listed above. Naturally, it can be easily predicted that similar effects can be expected for homologs other than those listed above. In particular, since the research on E.
- This protein is composed of 638 amino acids and consists of the "ATPase (ATP binding) domain" composed of amino acids 1-385 and the amino acid composed of amino acids 386-638 It consists of a “substrate binding domain” ( Figure 6).
- SEQ ID NO: 1 shows the sequence of the DNA K protein
- SEQ ID NO: 2 shows the gene sequence.
- HSP70 binds to nascent polypeptides and partially folded proteins and is known to help refold proteins that cannot be spontaneously folded. Richer groups to work It is known to recognize quality.
- FIG. 9 A remarkable improvement in the blocking efficiency was observed (FIG. 9).
- a remarkable improvement in the blocking efficiency was observed in Dna K 419-607.
- This protein appears to exhibit blocking in the manner shown in FIG. That is, it is considered that the structure of the hydrophobic domain was changed due to the change in the structure of the hydrophobic domain, and the improved hydrophobicity of the hydrophobic domain was linked to the improvement of the blocking ability.
- improvement in blocking ability means that amino acid substitution, delivery, insertion, and the like are performed on a candidate protein, and the blocking ability is improved as compared with the original protein or partial protein sequence.
- This improvement in blocking ability is preferably measured by the method described in claim 2.
- To improve the blocking ability there are a long-term blocking ability and a short-time blocking ability. It is sufficient that the blocking ability is improved in either or both.
- the present invention is a DnaK protein with improved blocking efficiency, wherein at least the amino acid sequence from the ⁇ terminus to the 387th position, at most up to the 472th position, has been removed. Further, the present invention is a Dna ⁇ protein having improved blocking efficiency, characterized in that at least the amino acid sequence from the ⁇ terminus to the 387th position, at most to the 418th position, has been removed. More preferably, it is a protein comprising the amino acid sequence of positions 419 to 607 of the DnaK protein.
- the present invention relates to a protein having improved blocking efficiency, wherein a hydrophilic amino acid in the DnaK protein from which the ATPase domain or a part thereof has been removed is partially substituted with a hydrophobic amino acid. is there. More specifically, a protein in which the amino acid sequence of the Dna K protein from which the ATPase domain or a part thereof has been removed has been removed, and aspartic acids at amino acids 479 and 481 have been substituted with valine. It is a protein with improved blocking efficiency. Still more preferably, a protein consisting of the amino acid sequence at positions 384 to 607 of the DnaK protein, in which the aspartic acids of amino acids 479 and 481 are substituted with valine, is used.
- modified means that the amino acid sequence has been modified by amino acid substitution, deletion, insertion, or the like of the candidate protein. This modification, after selecting the candidate protein or partial sequence of the protein, is based on the considerations shown above, (1) not to destroy the hydrophilic domain, (2) to make the hydrophobic domain more hydrophobic It is preferable to modify amino acids for the purpose of, for example, the following. Although not shown in the present invention, measures to make the hydrophilic domain more hydrophilic should be naturally considered.
- the present invention also relates to a protein for blocking having one or more hydrophilic domains and one or more hydrophobic domains, wherein the hydrophobic domain can be adsorbed on the vessel wall, and the hydrophilic domain is adsorbed on the vessel wall.
- Blocking protein capable of covering the hydrophobic domain.
- the domain as referred to herein is preferably a structural amino acid group consisting of 50 or more amino acids, and a partially deleted or added domain is also regarded as a domain.
- the present invention also specifies the blocking speed. That is, it is a modified protein characterized in that the blocking rate is higher than that of BSA. More specifically, a modified protein characterized in that the blocking ability in less than 10 minutes is superior to BSA under the same amount of protein so that the blocking efficiency is the same as BSA in blocking for 3 hours. It is.
- altered indicates that the gene sequence encoding the wild-type protein has been converted by amino acid substitution, deletion, insertion, or the like.
- the evaluation method is not particularly limited, but the methods shown in Examples 5 and 7 are preferably used, and the measurement is performed using non-specific adsorption of IgG or peroxidase to a polystyrene plate as an index.
- I g G As an evaluation method using the I g G is 1 to 1 0 minutes, preferably after 2 to 10 minutes blocking, PBS (-) was added human serum diluted in, 3 7 ° C '6 0 min After the incubation, the plate is washed and reacted with an optimal concentration of anti-human IgG antibody (peroxidase-bound). After washing, the amount of non-specifically adsorbed IgG is measured by the color development of TMBZ.
- peroxidase first, horseradish-derived peroxidase for labeling (PEO_131, manufactured by Toyobo Co., Ltd.) is dissolved in a protein solution whose blocking ability is to be measured at a concentration of 2 mg / ml.
- a dilution series is prepared with the same solution up to 40 to 320 times that of the peroxidase solution, and each dilution 1001 is dispensed into a 96-well polystyrene microplate. After leaving at room temperature for 1 hour, the solution is removed, and the plate is washed with a PBS buffer containing 0.02% Tween 20. Repeat this washing operation 6 times. After returning, remove the washing solution well. After adding tetramethylbenzidine and incubating at 37 ° C. for exactly 10 minutes, 1N sulfuric acid is added to stop the reaction and develop color. This color development is measured with a microplate reader at a main wavelength of 450 nm and a subwavelength of 650 nm.
- Example 7 it is also possible to add a diluted peroxidase solution to the previously blocked solid phase and measure its non-specific adsorption.
- concentration of the peroxidase solution used here is preferably 0.05 mgZm1. However, adjusting and using it so that it can be measured within the common sense will lead to more accurate evaluation.
- the dilution of peroxidase is preferably performed with PBS (-), but is not particularly limited.
- BSA Band Absorbent A
- BSA concentration As the BSA concentration used in this measurement, an amount that shows the same blocking efficiency as that of the sample protein at the third hour is used, but it is necessary to examine the concentration in advance.
- a buffer for dissolving those proteins 2 OmM Tris-HC1 (pH 7.0) or PBS (-) is preferably used, but is not particularly limited.
- the protein or protein fragment used in the present invention may have a tag.
- Tags include histidine tag, GST (daltathione-S-transferase) tag, MBP (mal) binding protein tag, F1ag tag, My c tag, and TAP (tandem affinity pilification) tag. Any tag may be employed, and any protein may be fused and used as necessary. An arbitrary amino acid sequence or the like may be added to a known tag.
- a tag which is not generally known or an arbitrary amino acid sequence may be added.
- a tag which is not generally known or an arbitrary amino acid sequence
- expression enhancement and restriction enzyme The addition of several amino acids is also conceivable from the relation of the weight.
- four amino acids of MRGS are added to the N-terminus of DnaK419-607N in Example 7.
- the position to be added may be N-terminal side or C-terminal side.
- the method for expressing the present protein is not particularly limited, but is preferably a method of expression using a prokaryote, and more preferably a method of expression using Escherichia coli.
- the expression vector is not particularly limited, and may be any vector that is generally used for expression.
- the crude purification solution is heated at an appropriate temperature and the centrifuged supernatant is purified, whereby the protein can be purified efficiently. Heating is preferably performed at 50 ° C or higher, more preferably at 70 ° C or higher.
- the substrate-binding domain of DnaK used in this study is also resistant to heat.
- the protein of the present invention having improved blocking efficiency can be applied to a blocking agent, an excipient, a stabilizing agent, a refolding aid, a coating agent, a medical coating agent and the like.
- a blocking agent in particular, it is expected to be used as a blocking agent in a detection system that utilizes an immune reaction, and is expected to be applicable to ELISA, immunohistochemical staining, western blotting, and the like.
- ELISA Enzyme—Linke d Immuno sorbent Assay
- One embodiment of the present invention is a blocking agent, excipient, stabilizer, and refolding aid containing .DnaK419-607.
- One embodiment of the present invention is a blocking agent, excipient, stabilizer, and refolding aid containing DnaK384-607 (D479V, D481V).
- DnaK384-607 D479V, D481V.
- hydrophilic amino acids were used as hydrophilic amino acids according to the definition of GENETYX.
- the hydrophobic amino acids were glycine, alanine, valine, leucine, isoleucine, methionine, phenylalanine, tryptophan and proline.
- the DNA fragment was cloned by amplifying the target gene fragment by PCR using genomic DNA extracted from E. coli K-12 strain as type III.
- KOD-P 1 us manufactured by Toyobo was used.
- the reaction buffer, ImM MgS04, the primers shown in SEQ ID NOs: 3 and 4 were added to 15 pmo 1 e, polymerase 1 unit and
- the DNA was prepared so as to be 100 ng of Enterobacteriaceae DNA, and the cycle of 94 ° C for 2 minutes, followed by 25 cycles of 15 seconds at 94 ° C, 30 seconds at 55 and 68 ° C for 1 minute was performed 25 times.
- DnaK386-586 was carried out using the primers shown in SEQ ID NOS: 3 and 4.
- the amplified DNA fragment was digested with the restriction enzyme BamHI and cloned into the BamHI-SmaI site of pQE30 (the DNA fragment amplified by KOD-P1us was blunt-ended). Therefore, the downstream side of the amplified fragment was used as it was).
- the sequence of the cloned gene was confirmed by sequence analysis. Cloning into this vector allows a 6 X His sequence (histidine sequence) to be added to the N-terminus of the target protein. G) can be added.
- an expression plasmid pQE-DnaK384-638 was prepared.
- the gene-introduced JM109 was cultured with shaking in LB medium for 16 hours, and the cells were collected by centrifugation and suspended in 20 mM Tris-HCl (pH 7.0). After sonication, the suspension was centrifuged at 15,000 rpm for 10 minutes using a high-speed microcentrifuge, and the supernatant was used. Specifically, it was purified using HI S-S elect HC Nickel Affinity Gel (manufactured by SI GMA), and finally purified against 2 OmM Tris-HC 1 (pH 7.0). Dialyzed overnight and used for experiments.
- Example 3 Preparation of C-terminal-removed DnaK clone and point mutant
- the C-terminal-removed DnaK clone can be prepared by using the pQE-DnaK384-638 prepared in Example 1 as type ⁇ using the Quick Change method. Was prepared by introducing stop codon into the site.
- DnaK 384-607 (D 479 V, D 481 V) used pQE-DnaK384-607 as a type III, and mutagenesis was performed using SEQ ID NOS: 11 and 12. After confirming the sequence of each of the prepared mutants by sequence analysis, proteins were prepared according to the method described in Example 1.
- Example 4 Production of N-terminal-removed Dna K clone
- PCR amplification was performed using the pQE-DnaK384-607 type III primer prepared in Example 2 and the following primers, and according to the method of Example 1, the BamHI-SmaI site of the pQE30 vector was used. Introduced into Set of clones and primers used are as follows: DnaK 508-607: SEQ ID NOs: 13 and 2, DnaK 525-607: SEQ ID NOs: 14 and 2, DnaK 419-607: SEQ ID NOs: 15 and 2. After confirming the sequence of each of the produced mutants by sequence analysis, proteins were prepared according to the method described in Example 1. Example 5 Blocking effect
- the blocking efficiency was measured using the following method.
- the study was performed using non-specific adsorption of human serum IgG on polystyrene plates as an index.
- BSA Sigma, Fraction on V
- 20 mM Tris-HCl pH 7.0
- various mutant Dna K samples 1001 were mixed with a polystyrene 96 ⁇ Elymno plate (Co star product; E.I.A./RI A 8We11 Strip) and allowed to stand at 4 ° C for 4 hours (Basically allowed to stand for 4 hours, but consider the blocking time If you set any time).
- normal human serum was diluted 50-fold with PBS (-), 50 z1 was added, and the mixture was incubated at 37 ° C for 1 hour.
- each well is washed four times with a washing solution of 201 (PBS (—), 0.05% Tween 20), and the antibody diluent (0.01 M PB (pH 7.4)) is adjusted to the optimal concentration.
- Peroxidase-labeled anti-human IgG antibody Jacks on ImmunoResearch 50 i1 diluted with 0.15 M NaC 0.5% casein
- was added to each well and the mixture was added at 37. Time incubated.
- each well was washed four times with 200 1 of a washing solution (PBS (—), 0.05% Tween 20), and a color reagent (tetramethylbenzidine (TMBZ: 3, 3 ', 5, 5') was used.
- TMBZ tetramethylbenzidine
- BSA, DnaK 384—638, DnaK 384—607, DnaK384—578, DnaK508—607, and DnaK 525-607 prepared at 0.7 mg / ml in 4 hours
- DnaK 384-638, and DnaK 384-607 had low blocking effects.
- DnaK 384-607 and DnaK 384-578 were used for the ⁇ -helix-cut, DnaK 508-607, and DnaK 525-607 for the / 3 sheet. It was a deleted clone, and it was speculated that 0 was required for blocking using the substrate binding domain of DnaK; both a helical structure and a ⁇ -sheet structure were required.
- BSA was prepared with the same concentration as DnaK 384-607 (D479 V, D481V) and DnaK 419-607 (7 mg / m 1 each) to improve the hydrophobicity of the ⁇ -sheet part.
- the blocking effect of 4 hours of blocking was compared with that of DNA 384-607 as a control.
- both DnaK 384-607 (D479V, D481V) and DnaK 419-607 had higher blocking efficiency than BSA at the same concentration, and were particularly remarkable with DnaK 419-607 (FIG. 9).
- anti-hCEA MoAb was diluted to 10 ⁇ g / m 1 with 50 mM carbonate buffer (pH 9.6), and 100 ⁇ l of the diluted solution was added to a polystyrene 96 ⁇ Elymno plate (Costar; E.I.A. /R.I.A8We11StriP), and allowed to stand for 37 * 1 hour.
- the plate was washed four times with a 150/21 washing solution, and then diluted with an optimal concentration of peroxidase-labeled anti-hCEA antibody (Imnoflora: Toyobo) After the reaction at 37 ° C * lh, the wells were further washed three times with 150 il of a washing solution (PBS (—), 0.05% Tween 20) Then, the substrate solution (tetramethylbenzidine (TMB Z: 3, 3 ', 5, 5'-Tetra meth thy 1 benzidine)) 100 1 was added, and the color was developed at 37 ° C for 20 minutes in the absence of light. H2 S04) 100 1 was added, and the yellow color development was measured at 450 nm / 650 nm.
- TMB Z tetramethylbenzidine
- Dna K fragments constructed in Examples 2 to 4 all have a histidine tag at the N-terminus derived from the expression vector pQE30, the Dna K fragment The isoelectric point has shifted to neutral pH. Therefore, a DnaK fragment from which the histidine tag had been deleted was constructed so that the original ability of blocking by electrostatic interaction could be maintained.
- Histidine tag removal DnaK clone was prepared by using the pQE-DnaK4 9-607 prepared in Example 5 as a ⁇ type and using the Quick Change method to remove Dn containing a histidine tag from the start codon. It was prepared by deleting the amino acids up to the aK region. Actually, a BamHI site was introduced upstream of the histidine tag by using Quic kCh e nge sid e ire c ct i ve m u t a ene s e s s ki t (manufactured by s sta tta gen e). The operation was performed according to the instruction manual.
- the primer sequences used at that time are shown in SEQ ID NOs: 16 and 17.
- a BamHI site is also provided upstream of the cloned gene. Therefore, a clone from which the histidine tag sequence has been removed can be obtained by digesting and religating the vector obtained with BamHI.
- This expression vector was named PQE-DnaK419-607N.
- the native DnaK419-607 fragment was prepared by culturing a transformant obtained by transforming Escherichia coli JM109 with this pQE-DnaK419-607N. That is, E. coli JM109 (pQE-DnaK419-607N) containing 100 mg / L of ampicillin in trophic broth (1.2% polypeptone, 2.4% yeast extract, 0.5% glycerol, 17 mM potassium phosphate 1 mM) , 72 mM dibasic phosphate) and cultured at 32 ° C. for 20 hours.
- Cells of 1 L of the main culture were collected by centrifugation, suspended in 200 ml of 100 mM Tris-HCl buffer, pH 9.0, and disrupted by a French press. Polyethyleneimine was added to the crushed liquid to a final concentration of 0.1%, and the mixture was heated at 60 ° C for 2 hours, and the supernatant was collected by centrifugation. Then, 50% saturated ammonium sulfate was added, and the precipitate was collected by centrifugation, and then redissolved in 100 mM Tris-HCl buffer, pH 9.0. The mixture was further heated at 64 ° C for 14 hours, and the supernatant was collected by centrifugation.
- the comparison of the blocking efficiency between BSA and the native DnaK419-607 fragment was measured by the following method.
- horseradish-derived peroxidase for labeling (TOYOBO (PE-131 made of glue) was dissolved at 2 mg / ml in a PBS buffer containing BSA or native DNA K 419-607 fragment.
- the commercially available BSA (fraction V) was adjusted to 2 or 1 Omg / m 1
- the native DnaK419-607 fragment was adjusted to 0.1 or 0.5 mg Zm 1.
- a dilution series was prepared up to 320 times, and each diluted solution 100 1 was dispensed into a 96-well microplate made of polystyrene, allowed to stand at room temperature for 1 hour, and then the solution was removed, containing 0.02% Tween 20 After washing with PBS buffer 200 u I.
- the present invention it becomes possible to easily screen a novel protein or partial sequence protein having a blocking ability based on amino acid sequence information.
- production of a protein with improved blocking efficiency, which can be expressed in a large amount became possible.
- the protein obtained by the present invention has a high blocking ability, and simple and reliable results can be obtained as compared with the conventional method.
- INDUSTRIAL APPLICABILITY The present invention greatly contributes to fields such as clinical diagnosis and medical treatment to which immunoassay is applied.
Abstract
Description
Claims
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JP2005511428A JPWO2005003155A1 (ja) | 2003-07-03 | 2004-07-02 | ブロッキング効率の向上したタンパク質 |
CN200480019080.XA CN1816562B (zh) | 2003-07-03 | 2004-07-02 | 封闭效率提高的蛋白质 |
US10/562,776 US7601504B2 (en) | 2003-07-03 | 2004-07-02 | Protein achieving improved blocking efficiency |
EP04747253A EP1642904A4 (en) | 2003-07-03 | 2004-07-02 | PROTEIN HAVING BETTER BLOCKING POWER |
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Cited By (5)
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JP2009051773A (ja) * | 2007-08-27 | 2009-03-12 | Toyobo Co Ltd | 細胞接着能を有するhsp70ファミリータンパク質 |
JP2010538651A (ja) * | 2007-09-14 | 2010-12-16 | アムジエン・インコーポレーテツド | 均質な抗体集団 |
JP2012092095A (ja) * | 2010-09-30 | 2012-05-17 | Sekisui Medical Co Ltd | 液状保存可能なタンパク質溶液及びタンパク質溶液の液状での保存方法 |
WO2016136918A1 (ja) * | 2015-02-25 | 2016-09-01 | 積水メディカル株式会社 | 免疫学的測定方法及び該方法に用いられる測定試薬 |
WO2016136917A1 (ja) * | 2015-02-25 | 2016-09-01 | 積水メディカル株式会社 | 免疫学的測定方法及び該方法に用いられる測定試薬 |
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EP3364189B1 (en) * | 2015-10-16 | 2021-02-03 | Toyobo Co., Ltd. | Immunochromatographic test piece |
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JPH0666803A (ja) * | 1992-06-26 | 1994-03-11 | Becton Dickinson & Co | 固相へ抗体をコーティングするための2段階法 |
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EP1149909A1 (en) * | 2000-04-28 | 2001-10-31 | Boehringer Mannheim Gmbh | Methods for regulating protein conformation using molecular chaperones |
CN1418954A (zh) * | 2001-11-12 | 2003-05-21 | 杭州华大基因研发中心 | 耐高温hsp70分子伴侣基因及其编码的多肽和制备方法 |
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Non-Patent Citations (1)
Title |
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PETERFI Z, KOCSIS B: "Comparison of blocking agents for an elisa for lps", J. IMMUNOASSAY, vol. 21, no. 4, November 2000 (2000-11-01), pages 341 - 354, XP002981795 * |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009051773A (ja) * | 2007-08-27 | 2009-03-12 | Toyobo Co Ltd | 細胞接着能を有するhsp70ファミリータンパク質 |
JP2010538651A (ja) * | 2007-09-14 | 2010-12-16 | アムジエン・インコーポレーテツド | 均質な抗体集団 |
JP2016145259A (ja) * | 2007-09-14 | 2016-08-12 | アムジエン・インコーポレーテツド | 均質な抗体集団 |
JP2012092095A (ja) * | 2010-09-30 | 2012-05-17 | Sekisui Medical Co Ltd | 液状保存可能なタンパク質溶液及びタンパク質溶液の液状での保存方法 |
JP2016222718A (ja) * | 2010-09-30 | 2016-12-28 | 積水メディカル株式会社 | 液状保存可能なタンパク質溶液及びタンパク質溶液の液状での保存方法 |
WO2016136918A1 (ja) * | 2015-02-25 | 2016-09-01 | 積水メディカル株式会社 | 免疫学的測定方法及び該方法に用いられる測定試薬 |
WO2016136917A1 (ja) * | 2015-02-25 | 2016-09-01 | 積水メディカル株式会社 | 免疫学的測定方法及び該方法に用いられる測定試薬 |
JPWO2016136918A1 (ja) * | 2015-02-25 | 2017-11-30 | 積水メディカル株式会社 | 免疫学的測定方法及び該方法に用いられる測定試薬 |
JPWO2016136917A1 (ja) * | 2015-02-25 | 2018-02-01 | 積水メディカル株式会社 | 免疫学的測定方法及び該方法に用いられる測定試薬 |
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EP1642904A1 (en) | 2006-04-05 |
JPWO2005003155A1 (ja) | 2006-11-16 |
US7601504B2 (en) | 2009-10-13 |
US20060183173A1 (en) | 2006-08-17 |
EP1642904A4 (en) | 2008-11-05 |
CN1816562B (zh) | 2011-09-07 |
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