Mechanism for producing mycotoxin

October 27, 2020

Three-dimensional structure of tenuazonic acid synthetase

A joint research team from RIKEN CSRS and Tottori University has ravealed the three-dimensional structure of the ketosynthase (KS) domain of TAS1, a biosynthetic enzyme of tenuazonic acid known as a mycotoxin (mold poison), providing important insights into the mechanism of the key reactions in tenuazonic acid biosynthesis.

Mycotoxins are chemical substances produced by fungi including plant pathogenic filamentous fungi. Their contamination on agricultural products leads to damage on human health and plant diseases, and the economic loss from this mycotoxin has been a serious concern.

The research team conducted an X-ray crystal structural analysis to reveal the three-dimensional structure of the KS domain of TAS1 from the rice blast fungus Pyricularia oryzae. By analyzing the functions of the enzyme based on the three-dimensional structure, the team obtained important findings on the cyclization reaction mechanism during the biosynthesis. The findings suggest that in the TAS1 KS domain, conserved amino acid residues among the ordinary KS domains are involved in the unique reaction. It was also suggested that the TAS1 KS domain has evolved to accept larger substrates than ordinary KS domains.

The results of this study are expected to enable highly efficient production control of tenuazonic acid. In addition, changing of the structure of tenuazonic acid may lead to creation of novel useful bioactive substances.

Original article
Journal of Biological Chemistry doi:10.1074/jbc.RA120.013105
C. Yun, K. Nishimoto, T. Motoyama, T. Shimizu, T. Hino, N. Dohmae, S. Nagano, H. Osada,
"Unique features of the ketosynthase domain in a nonribosomal peptide synthetase-polyketide synthase hybrid enzyme, tenuazonic acid synthetase 1".
Choong-Soo Yun; Research Scientist
Takayuki Motoyama; Senior Research Scientist
Hiroyuki Osada; Group Director
Chemical Biology Research Group