Site-specific modification of proteins is the modification of specific sites of proteins via chemical reactions so as to modify or label proteins. The site-specific modification of proteins requires strict reaction conditions: the reaction needs to be carried out in aqueous solution, while other side chain groups of the protein do not participate in the reaction. Prof. Ping Wang’s group at Shanghai Jiao Tong University (SJTU) has been working on the chemical synthesis and modification of proteins and peptides. Recently, Wang’s group collaborated with Researcher Yongtang Zheng’s group at Kunming Institute of Zoology of Chinese Academy of Sciences. They proposed a selective and rapid method for modifying the N-termini of proteins via a quinone-mediated oxidation and applied it to protein labeling, anti-HIV drug screening and other fields successfully.

The authors developed the method of protein bionic transamination. 

Figure 1. N-terminal selective transamination of proteins

Figure 2. Transamination of model peptides with different N-termini.

 
Figure 3. Quinone-mediated transamination reaction with proteins bearing free-Cys residues.

This method was applied to the modification of protein targets ubiquitin and myoglobin, and both the target oxime products and biotin-labeled myoglobin modification products were obtained with more than 70% conversion.

 
Figure 4. Late-stage modification of MIP-1β proteins via quinone-mediated selective oxidation of N-terminal amine.


MIP-1β (CCL4) exhibits potent anti-HIV-1 activity58 by binding to the hydrophobic transmembrane helix bundle of CCR5 via its N-terminal domain. The authors used this strategy to transaminase the N-terminus of CCL4 to swiftly obtain a series of modified proteins 29-45. The anti-HIV-1 activity assay demonstrated that the modified proteins 30 and 31 displayed significantly increased activity compared to CCL4. Their experiments showed that a large number of differently modified proteins could be obtained rapidly via the combination of protein chemical synthesis and site-specific modification, which paved the way for the preparation of anti-HIV protein-based drugs.


This paper was published in the journal Nature Communications (https://doi.org/10.1038/s41467-021-22654-7) with Prof. Ping Wang and Researcher Yangtang Zheng as co-corresponding authors and Siyao Wang, Qingqing Zhou, Xiaoping Chen and Ronghua Luo as co-first authors. Dr. Siyao Wang graduated from School of Chemistry at University of Sidney, Australia and joined Wang's group at SJTU as a postdoctoral fellow with the support of the China Postdoctoral Exchange Program. This work was also funded by the National Natural Science Foundation of China.

Translator:  Chenyun SUN

Reviser:  Xiaoke HU