新型毒素/抗毒素 z-bo 2020-10-16 306

　　Recently, Wang Xiaoxue, a researcher at the South China Sea Institute of Oceanology, the Chinese Academy of Sciences (the main research institute of tropical marine biological resources and ecology), worked with Professor Ouyang Songying from Fujian Normal University to study bacteria and paleontology. We discovered a large toxoid/antitoxin (TA) widely distributed in Japan. It has been proposed to name the new mechanism of action of the system "VIITA type".

　　TA systems are widely distributed in the prokaryotic genome, and 6 types of TA systems have been identified. In 2015, Dr. Wang Xiaoxue’s team Yao Jianyun and his colleagues discovered two adjacent genes in marine bacteria, including HEPN and MNT domains, forming a pair of TA systems. The toxin HepT has RNase activity and substrate. Discovery is a kind of mRNA. The special ratio of 6:2 constitutes a heterooctamer. Recent studies have shown that the antitoxin in the TA system antagonizes the toxicity of toxins in a new way. The antagonism is based on the antitoxin polyadenylation of the antitoxin. This mechanism of action is similar to the six reported so far. All types are different. Combining genetic, biochemical and structural analysis, MntA antitoxin has nuclear transferase activity and uses ATP as a substrate to place three AMPs in a tyrosine (Y) near the active site of toxin protein RNase. It turned out to be moving one by one. This change effectively reduces the toxicity of the toxin. The antitoxin MntA is the smallest member of the nucleic acid transferase family and the first novel nucleic acid transferase known to catalyze the transfer of multiple AMP molecules to the same amino acid residue in the protein. The study also found that the antitoxin active domain GSX10DXD and the key site Y of the toxin-modified RX4HXY are highly conserved in the TA family, indicating that this modification method is common in bacteria and paleontology.

　　related results have been published in "Nucleic Acid Research". The research team of Jianyun Yao and Dr. Xiangkai Ouyang are co-authors, and Xiaoxue Wang and Songying Ouyang are co-authors. This research was funded by the Postdoctoral Innovative Talent Support Program, the National Science Fund for Distinguished Young Scholars, the major projects of the Major Hydrosphere Microbiology Research Program, and the National Key Research and Development Program.