The Chemical Synthesis And Modification Of Bio-functional Protein Via The Development Of New Strategy Of Protein Chemical Synthesis

With the end of the Human Genome Project, the relationship between protein structure and function has become the forefront of the direction of the life sciences. Protein methylation, phosphorylation, glycosylation and ubiquitination received extensive attention to researchers. How to get high purity such proteins is the key studies to be carried out. Expression of conventional biological methods can only obtain a protein native amino acid sequence, but post-translational modified proteins are often difficult to obtain. Recently, artificial encode unnatural amino acids developed Schultz can be embedded into the non-natural amino acid in the target protein, thereby obtaining post-translational modifications of certain proteins. However, this method is low efficiency of protein expression, and can be embedded in a limited number of non-natural amino acid. Protein chemical synthesis technology is considered a powerful means for post-translational modification of proteins. Native chemical ligation developed by Kent has been successfully applied in many important protein synthesis. NCL involves a chemoselective amide formation reaction between a C-terminal peptide thioester and an N-terminal Cys peptide. However, C-terminal thioester for NCL could not be obtained by Fmoc solid phase synthesis method. To overcome this, Liu developed a peptide hydrazide method to achieve the C-terminal thioester peptide by Fmoc method. This method is simple and high efficiency coupling. In this paper, by using peptide hydrazide method, the author successfully synthetized the medicinal peptide Nesiritide. And by using peptide hydrazide as precursor, we prepared thioacid under mild conditions. Through this method, we synthetized the toxins Trifolitoxin and labeled the LC3 by fluorescent. In addition, we developed a new thiol reagent (MTG), it can be applied to one-pot ligation and desulfurization. We achieved the synthesis of ubiquitin protein by three fragments and two fragments.