Simulated enzymatic cleavage and activity analysis of phycoerythrin- derived bioactive peptides

Abstract

Red algae are naturally growing algae, and phycoerythrin is the main bioactive substance in red algae, possessing rich amino acid species and various biological activities, which is a high-quality protein raw material for the preparation of bioactive peptides. With the improvement of science and technology, bioinformatics technology can now be used to study the preparation of bioactive peptides. Compared with the method of conducting traditional experiments, the use of bioinformatics tools to study the target object has the advantages of reducing experimental costs and improving experimental efficiency. In this study, algal red protein was used as the research object. Firstly, bioinformatics tools were used to simulate enzymatic cleavage of seven algal red protein chains using pepsin (pH=1.3) and proteinase K together and to predict the bioactivity of the resulting peptides, and 65 biologically active peptides were found out of 302 peptides. Secondly, bioinformatics tools were used to predict the physicochemical properties and biological activities of the peptides, and 9 peptides with good non-toxic water solubility, immunomodulatory, antioxidant and antimicrobial properties with one or more biological activities were found. Finally, the peptides with high affinity to TLR2 receptor and KEAP1 receptor were screened by molecular docking software, and the molecular docking results of the peptides were visualized and analyzed using Pymol software. Through the above steps, nine active peptides of phycoerythrin such as SAADAAGRF, RDM, DAF, AGDP, KKF, SGDCSAL, SGDP, CRY and CAKGM were finally found to meet the expectation. Among these peptides, a total of 9 peptides had immunomodulatory properties, 6 peptides SAADAAGRF, DAF, AGDP, KKF, SGDCSAL and SGDP had antioxidant properties, and 4 peptides RDM, DAF, KKF and CAKGM had antimicrobial properties. The peptides SAADAAGRF, AGDP and DAF can spontaneously generate interaction force with TLR2 receptor, and all 9 peptides can spontaneously generate interaction force with KEAP1 receptor. All 9 peptides can be used as novel phycoerythrin active peptides, which can provide biological value for future research.