The Study Of A Novel Chemical Synthetic Method And Structure Of Disulfide-rich Peptide/Protein

In recent years, peptide and protein drugs which have strong targetting, high effect of the drug, low toxicity and easy metabolism in vivo have attracted considerable attention. Polypeptide/protein of toxin is a class of disulfide-rich peptide and have specific functions which take work through combining specific receptor protein of cell (as of the channel protein) with itself. These receptor proteins are usually important ion channels (as of the membrane protein) which related closely to cell differentiation and a variety of human diseases. Since the toxin protein is generated by the long-term evolutionary process of the nature, the specificity and efficiency with specific receptors of its are more well than the small molecule compounds obtained by high-throughput screening. Based on this, the toxin peptide/protein becomes the focus of attention in the area of peptide drug development, for it has well biological activity and high specificity. However, it is difficult to obtain this kind of protein with correct structure and function in great numbers by using recombinant expression of genes because of the special structure of the protein. In recent times, protein chemical synthesis has been developed to make up for shortness of traditional method, moreover, it has obvious advantages in productivity and efficiency. So protein chemical synthesis has been considered the most powerful means of obtaining polypeptide and protein by far. In this paper, the author obtained a series of disulfide-rich toxin peptide (Human ?-defensin-4, ?-conotoxin SIIIA and the sea anemone peptide APETX2) efficiently by using the method of peptide hydrazide and polypeptide/protein solid phase synthesis, and then got the homologous protein with spatial structure after refolding the peptides successfully. However, toxin polypeptides have low refolding yield and hard to isolate and purify due to abundant disulfide. To solve this problem, we learn from Tian group which introduce diaminodiacid into protein synthesis to optimize the synthesis and refolding of toxin polypeptide. Specifically, the use of diaminodiacid can reduce the rate of mispairing during the process of refolding and then improve the efficiency of synthesis and refolding significantly. An analogue of Hepcidin, which replace a pair of cysteine with diaminodiacid, was obtained successfully by using this strategy. Meanwhile it is proved that the strategy did improve combination efficiency and refolding efficiency of the analogue of Hepcidin.