The Study Of Chemical Synthesis Of Important Post-translational Modifier Poly-SUMO Protein

With the completion of the Human Genome Project,the relationship between protein structure and function has become a hot issue in current biology research.Particularly,the post-translational modifications(PTMs)of proteins has attracted extensive attention from researchers,such as methylation,phosphorylation,ubiquitination and ubiquitination-like.These post-translational modifications of proteins play important physiological functions in the organism.SUMO protein is a ubiquitin-like protein,which can be covalently coupled to certain substrate proteins by E1,E2,E3 tertiary enzyme-linked reaction to form SUMOylation protein.SUMOylation protein play an important role in nuclear translocation,signal transduction,DNA damage and repair and protein degradation in vivo.In the SUMOylation process,the SUMO protein itself can also be acetylated or polymerized,whereas the SUMO protein itself has the same effect on the function of the SUMOylation protein.To further study the function of acetylated SUMO and poly-SUMO proteins,it is critical task to obtain acetylated SUMO and poly-SUMO proteins in high purity.The traditional biological expression method can only obtain the protein composed of natural amino acids,while not obtain the post-translational modified protein,such as acetylated or polymerized proteins.Protein chemical synthesis is due to its ability to precisely build proteins at the atomic scale,becoming a very effective means to obtain these translational modified protein.Recently,Liu group developed hydrazide as a C-terminal thioester of masking group,simplifying the C-terminal thioester synthesis in the peptide fragment ligation,with the advantages of simple operation and high efficiency.We used peptide hydrazide method to the chemical synthesis of SUMO,acetylated SUMO,D-SUMO and Di-SUMO protein and obtained two fragments synthesis of SUMO,acetylated SUMO,D-SUMO,and N-to-C-terminal four fragments synthesis of Di-SUMO protein.And the correctness of the synthetic proteins was verified by biochemical experiments.This work provides a universal approach for further chemical synthesis of poly-ubiquitin and poly-ubiquitin-like proteins,which provide an effective tool to the study of the biochemical mechanisms of protein ubiquitination-specific synthesis,recognition,and degradation processes.