Open AccessStructural basis for selectivity in a highly reducing type II polyketide synthase
Author(s) -
Danyao Du,
Yoshihiko Katsuyama,
Masanobu Horiuchi,
Shinya Fushinobu,
Aochiu Chen,
Thomas B. Davis,
Michael D. Burkart,
Yasuo Ohnishi
Publication year - 2020
Publication title -
nature chemical biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.412
H-Index - 216
eISSN - 1552-4469
pISSN - 1552-4450
DOI - 10.1038/s41589-020-0530-0
Subject(s) - acyl carrier protein , polyketide , polyketide synthase , stereochemistry , chemistry , polyene , biosynthesis , mutagenesis , escherichia coli , active site , protein structure , enzyme , biochemistry , gene , mutation
In type II polyketide synthases (PKSs), the ketosynthase-chain length factor (KS-CLF) complex catalyzes polyketide chain elongation with the acyl carrier protein (ACP). Highly reducing type II PKSs, represented by IgaPKS, produce polyene structures instead of the well-known aromatic skeletons. Here, we report the crystal structures of the Iga11-Iga12 (KS-CLF) heterodimer and the covalently cross-linked Iga10=Iga11-Iga12 (ACP=KS-CLF) tripartite complex. The latter structure revealed the molecular basis of the interaction between Iga10 and Iga11-Iga12, which differs from that between the ACP and KS of Escherichia coli fatty acid synthase. Furthermore, the reaction pocket structure and site-directed mutagenesis revealed that the negative charge of Asp 113 of Iga11 prevents further condensation using a β-ketoacyl product as a substrate, which distinguishes IgaPKS from typical type II PKSs. This work will facilitate the future rational design of PKSs.