A screening method for molecularly mimicking bisphenol A-specific peptides

Abstract

This invention proposes a method for screening bisphenol A-specific peptides using molecular simulation, belonging to the field of food safety technology. The method includes the following steps: 1) Through protein stacking and molecular docking, the molecular structure and interactions of bisphenol A-protein cocrystal compounds in a protein structure database are comprehensively analyzed to obtain the receptor protein and the original parent chain; 2) Based on the original parent chain obtained in step 1), the parent peptide is obtained by truncation of the parent peptide segment by analyzing the main active amino acids in the molecular docking results; 3) By performing virtual amino acid mutations on the parent peptide obtained in step 2), a peptide library specifically binding to bisphenol A is constructed, and molecular dynamics is used for preliminary screening of the peptides; 4) The peptide chains screened in step 3) are used as specific recognition elements, and peptides labeled with fluorescein isothiocyanate are used to form specific recognition probes. The specific recognition probes are mixed with bisphenol A, and the peptide sequences with the strongest specific binding ability to bisphenol A are screened based on the different fluorescence differences. This invention is mainly applied to the screening of specific recognition elements for toxic and harmful small molecules, active ingredients, and functional factors. This method avoids the complex preparation steps of antibodies and the cumbersome screening process of aptamers, achieving high-throughput design of specific recognition elements.

Description

Technical Field

[0001] This invention belongs to the field of food safety technology, and in particular relates to a screening method for molecularly mimicking bisphenol A-specific peptides. Background Technology

[0002] Bisphenol A (BPA) is an endocrine disruptor. Its structure is similar to that of endogenous estrogen, giving it estrogen-like effects. It is widely used in the industrial production of polycarbonate plastics, epoxy resins, and thermal paper. Due to its large-scale production and widespread application, it is ubiquitous in the environment. BPA can enter the human body through various routes, such as the digestive tract, respiratory tract, and skin. Studies have shown that BPA can interfere with the endocrine system, reduce immune function, impair reproductive capacity, cause precocious puberty in newborns, increase the incidence of prostate cancer, breast cancer, and uterine cancer, and is also associated with obesity, diabetes, heart disease, and asthma.

[0003] my country's GB 9685-2016 "National Food Safety Standard for the Use of Additives in Food Contact Materials and Articles" stipulates relevant requirements for additives used in food contact materials and articles. The migration limit for bisphenol A (BPA) is 0.6 mg / kg, and it explicitly states that BPA cannot be used in the manufacture of food contact materials and articles specifically for infants and young children. In 2018, the European Commission issued Regulation (EU) 2018 / 213, revising the requirements for BPA migration in food contact materials and compliance declarations. The migration limit for BPA in food contact varnishes and coatings is 0.05 mg / kg, and BPA must not be detected in infant formula, follow-up formula, infant cereals, baby food, special medical purpose foods to meet the nutritional needs of young children, infant milk-based beverages, or similar products using varnishes and coatings. Therefore, establishing a rapid, sensitive, and accurate detection method is crucial.

[0004] Currently, one of the key steps in commonly used immunoassay techniques is the preparation of highly specific antibodies. However, antibody preparation is complex, and animal immunization has a certain failure rate. This "trial and error" approach is time-consuming and labor-intensive, becoming a bottleneck for rapid detection technologies.

[0005] With the accumulation of achievements in bioinformatics, research using molecular simulation to virtually bind, screen, and simulate interactions between components is constantly increasing. Computer simulation technology is used to simulate molecular docking between acceptors and ligands, and virtual amino acid mutations are used to explain the interactions between amino acid residues in the CDR region of proteins. The biological properties of the structure altered by virtual amino acid mutations can improve overall affinity and stability. Simultaneously, molecular dynamics can simulate real experimental environments, further optimizing conformations. Therefore, it is necessary to establish a method for screening bisphenol A-specific peptides using molecular simulation technology.

[0006] In recent years, antibody-specific recognition elements (aptamers, small molecule antibodies, molecularly imprinted polymers, etc.) have become a research hotspot. Peptides are a class of substances between amino acids and proteins, possessing advantages such as small molecular weight, high activity, strong specificity, non-immunogenicity, and ease of synthesis. They also exhibit structural diversity, specificity, and binding affinity to target analytes. Therefore, they can be used as specific recognition elements in the establishment of practical detection methods. Summary of the Invention

[0007] This invention proposes a method for screening molecularly simulated bisphenol A-specific peptides and a method for detecting bisphenol using bisphenol A-specific peptides, in order to solve the above-mentioned technical problems.

[0008] This invention proposes a method for screening molecularly mimicking bisphenol A-specific peptides, comprising the following steps:

[0009] 1) By protein stacking and molecular docking, the molecular structure and interactions of bisphenol A-protein cocrystal compounds in the protein structure database are comprehensively analyzed to obtain the receptor protein and the original parent chain;

[0010] 2) Based on the original parental chain obtained in step 1), the parental peptide was obtained by cleaving the parental peptide segment by analyzing the main amino acids in the molecular docking results.

[0011] 3) By performing virtual amino acid mutations on the parental peptides obtained in step 2), a peptide library that specifically binds to bisphenol A was constructed, and molecular dynamics was used to perform preliminary screening of the peptides.

[0012] 4) Using the polypeptide chains obtained in step 3) as specific recognition elements, label the polypeptides with fluorescein isothiocyanate to form specific recognition probes, mix the specific recognition probes with bisphenol A, and screen out the polypeptide sequences with the strongest specific binding ability to bisphenol A based on the different fluorescence differences.

[0013] Further, step 1) specifically includes:

[0014] Bisphenol A-protein cocrystal compounds were searched in the protein structure database. All retrieved protein structures were imported into the molecular simulation platform, molecular docking was run, and the docking results were analyzed. The protein with the highest interaction score in the docking results was selected as the original protein. Bisphenol A-protein cocrystal compounds were searched in the protein structure database, and all retrieved protein structures were imported into the molecular simulation platform. Protein superposition was run, and the superposition results were analyzed. The molecular structure and interaction sites of the bisphenol A-protein complex were analyzed, and the protein with the highest concentration of major interacting amino acids was selected as the parent chain.

[0015] Further, step 2) specifically includes:

[0016] Based on the original parent chain, the major amino acids of the ligand and the 2D interaction diagram in the molecular docking results were analyzed. Peptide chains were truncated according to the principle of including as many major amino acids as possible. Molecular docking was performed on all truncated peptide chains and ligands, and peptide chains with higher docking score function values ​​were selected.

[0017] Furthermore, in step 2), the range of ligand binding for peptide chain cleavage is... The temperature is 298.15K.

[0018] Further, in step 3), constructing a polypeptide library that specifically binds to bisphenol A by performing virtual amino acid mutations on the above-mentioned parental polypeptides specifically involves:

[0019] The peptide chains with high docking scoring function values ​​were subjected to virtual amino acid mutations. First, site-directed mutagenesis based on stability was used to determine the key amino acids. Then, saturation mutations were performed on the key amino acids to determine the optimal mutation type.

[0020] Randomly permutate and combine all saturation mutation results to obtain all combination result sequences;

[0021] All combined sequences were assembled into a peptide library, and all combined sequences in the peptide library were molecularly docked with bisphenol A. The functional scores of all docking results were analyzed, and then the six peptide chains with the higher energy scores of the result sequences were selected.

[0022] Furthermore, in step 3), the preliminary screening of peptides using molecular dynamics specifically involves:

[0023] Molecular dynamics simulations were performed on six polypeptide chains from the polypeptide library to simulate the specific recognition ability of the polypeptides with bisphenol A under room temperature solution conditions.

[0024] The peptide conformation of the last frame after molecular dynamics simulation was selected for molecular docking with bisphenol A. The docking results were analyzed, and the two peptide chains with the highest scores were selected.

[0025] The present invention also proposes a method for detecting bisphenol A using any of the aforementioned bisphenol A-specific peptides, comprising the following steps:

[0026] (1) Synthesis of specific fluorescent probes: The screened bisphenol A specific peptides were coupled with fluorescein isothiocyanate through a carbamate reaction. The fluorescein isothiocyanate labeled peptides were used to synthesize specific fluorescent probes that specifically recognize bisphenol A.

[0027] (2) Specific recognition of probe with bisphenol A: Add bisphenol A solution to the solution of the specific fluorescent probe obtained in step (1) and shake to incubate, so that the probe can specifically recognize the target.

[0028] (3) Fluorescence quenching: After the probe and target are incubated in step (2), graphene oxide dispersion is added to the system to quench the fluorescence of probes that have not bound to the target based on the principle of fluorescence resonance energy transfer;

[0029] (4) Detection of fluorescence intensity value: After the treatment in step (3), bisphenol A binds to a specific fluorescent probe, and after being quenched by graphene oxide, the fluorescence intensity of the solution is measured. The relationship between the fluorescence difference and the concentration of bisphenol A is analyzed.

[0030] This invention has the following advantages:

[0031] This invention proposes an optimized screening method for bisphenol A-specific peptides. Utilizing the Discovery Studio molecular simulation platform, it analyzes protein action sites, constructs a specific peptide library, and uses FITC-labeled peptides to form specific recognition probes. This optimized screening of specific peptides provides a novel approach for the preparation of specific recognition elements. This method avoids the complex antibody preparation steps and the tedious aptamer screening process, significantly shortening experimental time and saving costs. It also avoids interference from human error and uncontrollable environmental factors, enabling high-throughput design of specific recognition elements and providing strong technical support for the establishment of rapid detection methods. Attached Figure Description

[0032] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0033] Figure 1 This is a flowchart illustrating the steps of the screening method for molecularly simulated bisphenol A-specific peptides described in this embodiment of the invention.

[0034] Figure 2 This is a standard curve diagram as described in an embodiment of the present invention. Detailed Implementation

[0035] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0036] The present invention will be described in detail below with reference to embodiments.

[0037] One embodiment of the present invention proposes a method for screening molecularly mimicking bisphenol A-specific peptides, comprising the following steps:

[0038] 1) By protein stacking and molecular docking, the molecular structure and interactions of bisphenol A-protein cocrystal compounds in the protein structure database are comprehensively analyzed to obtain the receptor protein and the original parent chain;

[0039] 2) Based on the original parental chain obtained in step 1), the parental peptide was obtained by cleaving the parental peptide segment by analyzing the main amino acids in the molecular docking results.

[0040] 3) By performing virtual amino acid mutations on the parental peptides obtained in step 2), a peptide library that specifically binds to bisphenol A was constructed, and molecular dynamics was used to perform preliminary screening of the peptides.

[0041] 4) Using the polypeptide chains screened in step 3) as specific recognition elements, label the polypeptides with fluorescein isothiocyanate (FITC) to form specific recognition probes. Mix the specific recognition probes with bisphenol A, and screen out the polypeptide sequences with the strongest specific binding ability to bisphenol A based on the different fluorescence differences.

[0042] This invention proposes an optimized screening method for bisphenol A-specific peptides. Utilizing the Discovery Studio molecular simulation platform, protein interaction sites are analyzed, a specific peptide library is constructed, and specific peptides are optimized for screening. This method can be applied to the screening of small molecule specific peptides. The peptide is used as a specific recognition element and conjugated with fluorescein isothiocyanate (FITC) to synthesize a specific recognition fluorescent probe. After fluorescence quenching by adding the target analyte probe, the peptide with the best specific recognition ability for the target analyte is screened based on the difference in fluorescence values.

[0043] Further, step 1) specifically includes:

[0044] Bisphenol A-protein cocrystal compounds were searched in the protein structure database. All retrieved protein structures were imported into the molecular simulation platform, molecular docking was run, and the docking results were analyzed. The protein with the highest interaction score in the docking results was selected as the original protein. Bisphenol A-protein cocrystal compounds were searched in the protein structure database, and all retrieved protein structures were imported into the molecular simulation platform. Protein superposition was run, and the superposition results were analyzed. The molecular structure and interaction sites of the bisphenol A-protein complex were analyzed, and the protein with the highest concentration of major interacting amino acids was selected as the parent chain.

[0045] Further, step 2) specifically includes:

[0046] Based on the original parent chain, the major amino acids of the ligand and the 2D interaction diagram in the molecular docking results were analyzed. Peptide chains were truncated according to the principle of including as many major amino acids as possible. Molecular docking was performed on all truncated peptide chains and ligands, and peptide chains with higher docking score function values ​​were selected.

[0047] Furthermore, in step 2), the range of ligand binding for peptide chain cleavage is... The temperature is 298.15K.

[0048] Furthermore, in step 2), the seven peptide chains with higher docking values ​​are selected based on the scoring function value for further research.

[0049] Step 3 in this embodiment of the invention is mainly to further improve the stability of the specific binding between the polypeptide and bisphenol A.

[0050] Further, in step 3), the construction of a polypeptide library specifically binding to bisphenol A by performing virtual amino acid mutations on the parental polypeptide obtained in step 2) is specifically as follows:

[0051] The peptide chains with high docking scoring function values ​​were subjected to virtual amino acid mutations. First, site-directed mutagenesis based on stability was used to determine the key amino acids. Then, saturation mutations were performed on the key amino acids to determine the optimal mutation type.

[0052] Randomly permutate and combine all saturation mutation results to obtain all combination result sequences;

[0053] All combined sequences were assembled into a peptide library, and all combined sequences in the peptide library were molecularly docked with bisphenol A. The functional scores of all docking results were analyzed, and then the six peptide chains with the higher energy scores of the result sequences were selected.

[0054] Furthermore, in step 3), the preliminary screening of peptides using molecular dynamics specifically involves:

[0055] Molecular dynamics simulations were performed on six polypeptide chains from the polypeptide library to simulate the specific recognition ability of the polypeptides with bisphenol A under room temperature solution conditions.

[0056] The peptide conformation of the last frame after molecular dynamics simulation was selected for molecular docking with bisphenol A. The docking results were analyzed, and the two peptide chains with the highest scores were selected.

[0057] In step 4) of this embodiment, the polypeptide is labeled with fluorescein isothiocyanate (FITC) to form a specific recognition probe. Fluorescein isothiocyanate (FITC) is a yellow or orange-yellow crystalline powder with stable physicochemical properties, exhibiting bright yellow-green fluorescence in solution. The FITC molecule contains an isothiocyanate group, which, under alkaline conditions, can carbamate with the primary amine group of a protein to form a thiourea bond, thereby enabling protein labeling without altering the protein's biological activity.

[0058] Furthermore, the same amount of bisphenol A can be added to the reaction system, and the polypeptide sequence with the strongest specific binding ability to bisphenol A can be screened based on the different fluorescence differences.

[0059] An embodiment of the present invention also proposes a method for detecting bisphenol using any of the above-mentioned bisphenol A-specific polypeptides, comprising the following steps:

[0060] (1) Synthesis of specific fluorescent probes: The screened bisphenol A specific peptides were coupled with fluorescein isothiocyanate through a carbamate reaction. The fluorescein isothiocyanate labeled peptides were used to synthesize specific fluorescent probes that specifically recognize bisphenol A.

[0061] (2) Specific recognition of probe with bisphenol A: Add bisphenol A solution to the solution of the specific fluorescent probe obtained in step (1) and shake to incubate, so that the probe can specifically recognize the target.

[0062] (3) Fluorescence quenching: After the probe and target are incubated in step (2), graphene oxide dispersion is added to the system to quench the fluorescence of probes that have not bound to the target based on the principle of fluorescence resonance energy transfer;

[0063] (4) Detection of fluorescence intensity value: After the treatment in step (3), bisphenol A binds to a specific fluorescent probe, and after being quenched by graphene oxide, the fluorescence intensity of the solution is measured. The relationship between the fluorescence difference and the concentration of bisphenol A is analyzed.

[0064] Further, step (1) specifically involves: slowly adding the FITC solution to the peptide solution at a FITC to peptide mass ratio of 2:1 to 5:1, and stirring magnetically for 3-8 hours at room temperature in the dark.

[0065] Further, step (2) specifically involves incubating the probe obtained in step (1) and bisphenol A in a constant temperature shaking mixer for 5-10 minutes.

[0066] Further, step (3) specifically involves adding the graphene oxide dispersion dropwise to the reaction system of step (2) and incubating it in a constant temperature shaking mixer for 5-30 minutes; wherein the concentration of the graphene oxide dispersion is 1 mg / mL.

[0067] Further, step (4) specifically involves transferring 200 μL of the reaction system solution from step (3) into a quartz cuvette and measuring it using a fluorescence spectrophotometer.

[0068] In this embodiment of the invention, different concentrations of bisphenol A can be configured to measure fluorescence intensity according to steps (1)-(4) to establish a bisphenol A fluorescence detection method.

[0069] The applications described in the embodiments of this invention can be extended to the construction of rapid detection methods for food safety, such as test strips, reagent kits, and immunosensors; they can also be extended to the field of food quality control for the monitoring of active ingredients in food.

[0070] The present invention will now be described in detail with reference to the embodiments.

[0071] Example 1 A method for screening molecularly mimicking bisphenol A-specific peptides includes the following steps:

[0072] First, a comprehensive analysis of the molecular structure and interactions of bisphenol A-protein cocrystal compounds in the PDB library was conducted to obtain the receptor protein.

[0073] Search for bisphenol A-protein cocrystals in the PDB library. Import all retrieved protein structures into Discovery Studio molecular simulation software. Delete water molecules from the complex. Run Prepare Protein to process the protein, define the protein docking site, set the input acceptor to 2E2R, select bisphenol A:All as the input ligand, set the conformational cluster radius to 0.5, and leave other parameters as default. Click Run to perform CDOCKER semi-flexible molecular docking. Analyze the molecular docking results, and use the protein with the highest interaction score as the original parent chain.

[0074] Second, molecular docking and peptide chain truncation

[0075] Based on the molecular docking and protein superposition results, 2E2R was selected as the original parent chain. The major binding amino acids of the ligands and the 2D interaction diagram in the molecular docking results were analyzed to determine the major binding amino acid peptide. Peptide truncation was performed based on the principle of including as many major binding amino acids as possible. The binding range of the ligands in the truncated peptide segment was [not specified]. The temperature was 298.15 K. Molecular docking was performed on all the truncated peptide chains and ligands, and the 7 peptide chains with the highest docking score function values ​​were selected.

[0076] Third, constructing a peptide library that specifically binds to bisphenol A through virtual amino acid mutation.

[0077] Select the ligand-binding chains from the docking results. Amino acid residues within the range were used as major amino acids. Stability-based virtual amino acid site-directed mutagenesis was performed on the major amino acids to determine key amino acids. Then, saturation mutagenesis was performed on the key amino acids to determine the optimal mutation type. The consistency with the stability mutation results was verified by affinity-based virtual amino acid mutagenesis. Finally, the mutation results were randomly arranged and combined to form a polypeptide sequence library. Molecular docking was used to dock all polypeptide sequences in the library with bisphenol A. The docking results were analyzed to screen out the 6 peptide chains with the highest energy scores.

[0078] Fourth, molecular dynamics is used for preliminary screening of peptides.

[0079] Molecular dynamics simulations were performed on the six selected polypeptide chains under room temperature conditions. Further structural optimization was conducted on specific polypeptide chains to best represent their actual state, with a temperature parameter set at 298.15 K. After the molecular dynamics simulations were completed, the last frame was selected as the receptor structure for molecular docking with the ligand. Based on the scoring, the two polypeptide chains S1 and S2 were selected for final practical validation. The specific amino acid sequences and interaction energies are shown in Table 1.

[0080] Table 1. Peptide chain sequence and molecular docking energy score

[0081]

[0082] Fifth, specific peptides are screened using a rapid fluorescence detection method for final selection.

[0083] The difference in fluorescence intensity generated by the different binding abilities of specific fluorescent probes to graphene oxide and bisphenol A is used to compare the specificity of polypeptide chains, thereby screening for polypeptides suitable for practical experiments. The specific steps are as follows:

[0084] (1) Synthesis of specific fluorescent probes: The specific method is as follows: Fluorescein isothiocyanate (FITC) solution is slowly added to the peptide solution at a ratio of FITC to peptide of 3:1, and the solution is stirred magnetically for 4 hours in the dark at room temperature.

[0085] (2) The probe specifically recognizes bisphenol A. The specific method is as follows: Add 150 μL of the specific fluorescent probe to a brown centrifuge tube, and add 80 μL of bisphenol A standard solution to the centrifuge tube. Place the centrifuge tube in a constant temperature shaking mixer and incubate in the dark for ten minutes.

[0086] (3) Fluorescence quenching of specific fluorescent probes: After adding bisphenol A and incubating for ten minutes, add 60 μL of 0.5 mg / mL graphene oxide (fluorescence quencher) dispersion to the centrifuge tube and continue incubation for 5 minutes.

[0087] (4) Based on the principle of fluorescence resonance energy transfer, specific peptides were evaluated and screened. The order of specific binding ability of peptide chains to bisphenol A was S1>S2. Therefore, S1 can be selected as the specific recognition element for subsequent research.

[0088] Experimental Example 1 Establishment of a rapid fluorescence detection method based on S1

[0089] The specific steps are as follows:

[0090] (1) Synthesis of specific fluorescent probes, the specific method is as follows:

[0091] Take 300 μL of 0.01 mg / mL FITC solution and slowly add it dropwise to 1 mL of 0.001 mg / mL peptide solution. Place the brown glass bottle containing the reaction solution on a magnetic stirrer and stir at room temperature in the dark for 4 hours.

[0092] (2) The probe specifically recognizes bisphenol A, and the specific method is as follows:

[0093] Take 100 μL of the synthesized specific fluorescent probe into a 1.5 mL brown centrifuge tube, add 100 μL of bisphenol A standard solution to the centrifuge tube, and place the centrifuge tube in a constant temperature mixing shaker and incubate at 37 °C in the dark for 7 minutes.

[0094] (3) Quenching of specific fluorescent probes, the specific method is as follows:

[0095] Add 30 μL of 1 mg / mL graphene oxide dispersion to the brown centrifuge tube from step (2) and continue incubation at 37°C in the dark for ten minutes.

[0096] (4) The specific method for measuring the fluorescence intensity of the solution is as follows:

[0097] Take 200 μL of the solution from the brown centrifuge tube and transfer it to a quartz fluorescence cuvette. Place the cuvette in a fluorescence spectrophotometer to measure the fluorescence intensity of the solution.

[0098] (5) Method establishment

[0099] 100 μL of bisphenol A standard solutions of different concentrations were added dropwise to 100 μL of a specific fluorescent probe solution and incubated at room temperature in the dark for 7 min. Immediately after 7 min, 30 μL of 1 mg / mL graphene oxide was added dropwise to the reaction system, and the system was incubated at room temperature in the dark for 10 min. The fluorescence intensity of the solution was measured immediately after the incubation period. The fluorescence difference between the blank control group (without bisphenol A solution) and the experimental group was calculated to show a linear relationship with the bisphenol A concentration in the range of 60-500 mg / mL. A standard curve was constructed for bisphenol A concentration versus fluorescence difference. The results are shown below. Figure 2 As shown.

[0100] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for detecting bisphenol A using a bisphenol A specific polypeptide, characterized by, Comprise the following steps: (1) synthesis of specific fluorescent probe: the bisphenol A specific polypeptide obtained by screening is coupled with fluorescein isothiocyanate by carbamidation reaction, and the fluorescein isothiocyanate labeled polypeptide is synthesized into specific fluorescent probe which specifically recognizes bisphenol A; (2) specific recognition of probe and bisphenol A: add bisphenol A solution to the solution of specific fluorescent probe obtained in step (1) and shake incubate, so that the probe specifically recognizes the target; (3) fluorescence quenching: after the incubation of probe and target in step (2) is completed, add graphene oxide dispersion to the system, and based on the principle of fluorescence resonance energy transfer, quench the fluorescence of the probe which does not combine with the target; (4) detect the fluorescence intensity value: after step (3), bisphenol A combines with specific fluorescent probe, and the fluorescence intensity of the solution is measured after being quenched by graphene oxide, and the relationship between the fluorescence difference value and the concentration of bisphenol A is analyzed; Wherein, the bisphenol A specific polypeptide is obtained by the screening method of molecular simulation bisphenol A specific polypeptide, and the screening method comprises the following steps: Step 1) by protein superposition and molecular docking, comprehensively analyze the molecular structure and interaction of bisphenol A-protein co-crystal compound in protein structure database to obtain receptor protein and original parent chain; Step 2) according to the original parent chain obtained in step 1), analyze the main action amino acid in the molecular docking result to obtain the parent peptide segment, and obtain the parent polypeptide; Step 3) by virtual amino acid mutation of the parent polypeptide obtained in step 2), construct a polypeptide library which specifically binds with bisphenol A, and use molecular dynamics to preliminarily screen the polypeptide; Step 4) the polypeptide chain obtained by screening in step 3) is used as a specific recognition element, and the fluorescein isothiocyanate labeled polypeptide is used to form a specific recognition probe, the specific recognition probe is mixed with bisphenol A, and the polypeptide sequence with the strongest specific binding ability with bisphenol A is screened according to the different fluorescence difference values.

2. The method of claim 1, wherein: Step 1) is specifically: Search for bisphenol A-protein co-crystal compounds in the protein structure database, import all retrieved protein structures into the molecular simulation platform, run molecular docking and analyze the molecular docking results, and select the protein with the highest docking score as the original protein; search for bisphenol A-protein co-crystal compounds in the protein structure database, import all retrieved protein structures into the molecular simulation platform, run protein superposition and analyze the protein superposition results, analyze the molecular structure and action site of bisphenol A-protein complex, and select the protein with the most concentrated main action amino acid as the parent chain.

3. The method of claim 1, wherein: Step 2) is specifically: According to the original parent chain, analyze the main action amino acid and 2D interaction diagram in the molecular docking result, and cut the peptide chain according to the principle of containing as many main action amino acids as possible; molecular docking is carried out on all cut peptide chains and ligands, and the peptide chain with higher docking scoring function value is selected.

4. The method of claim 3, wherein: In step 2), the range of ligand binding of peptide chain cutting is 2-4 Å, and the temperature is 298.15 K.

5. The method of claim 3, wherein: in step 3), the polypeptide library specifically binding to bisphenol A is constructed by virtual amino acid mutation of the parent polypeptide; the peptide chains with higher docking score function values are subjected to virtual amino acid mutation, and the key amino acids are determined by using virtual amino acid site-directed mutation based on stability, and then the key amino acids are subjected to saturation mutation to determine the optimal mutation type; all the saturation mutation results are subjected to random permutation and combination to obtain all the combined result sequences; all the combined result sequences are combined to form a polypeptide library, and all the combined result sequences in the polypeptide library are subjected to molecular docking with bisphenol A; the docking result function score values are analyzed, and then 6 polypeptide chains with higher energy score values are selected from the result sequences.

6. The method of claim 5, wherein: in step 3), the preliminary screening of the polypeptide by using molecular dynamics is specifically as follows: the 6 polypeptide chains in the polypeptide library are subjected to molecular dynamics simulation to simulate the specific recognition ability of the polypeptide and bisphenol A in a solution at room temperature; the conformation of the polypeptide in the last frame after the molecular dynamics simulation is subjected to molecular docking with bisphenol A, the docking result is analyzed, and 2 polypeptide chains with the highest score values are selected.

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