Expanding the Structural Diversity of Drimentines by Exploring the Promiscuity of Two N-methyltransferases

Tingting Yao; Jing Liu; Enjing Jin; Zengzhi Liu; Huayue Li; Qian Che; Tianjiao Zhu; Dehai Li; Wenli Li

doi:10.1016/j.isci.2020.101323

Expanding the Structural Diversity of Drimentines by Exploring the Promiscuity of Two N-methyltransferases

iScience. 2020 Jul 24;23(7):101323. doi: 10.1016/j.isci.2020.101323. Epub 2020 Jun 28.

Authors

Tingting Yao¹, Jing Liu¹, Enjing Jin¹, Zengzhi Liu¹, Huayue Li², Qian Che², Tianjiao Zhu², Dehai Li², Wenli Li³

Affiliations

¹ Key Laboratory of Marine Drugs, Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China.
² Key Laboratory of Marine Drugs, Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China; Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
³ Key Laboratory of Marine Drugs, Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China; Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao, China. Electronic address: liwenli@ouc.edu.cn.

Abstract

Methylation is envisioned as a promising way to rationally improve key pharmacokinetic characteristics of lead compounds. Although diverse tailoring enzymes are found to be clustered with cyclodipeptide synthases (CDPSs) to perform further modification reactions on the diketopiperazine (DKP) rings generating complex DKP-containing compounds, so far, a limited number of methyltransferases (MTs) co-occurring with CDPS have been experimentally characterized. Herein, we deciphered the methylation steps during drimentines (DMTs) biosynthesis with identification and characterization of DmtMT2-1 (from Streptomyces sp. NRRL F-5123) and DmtMT1 (from Streptomyces youssoufiensis OUC6819). DmtMT2-1 catalyzes N4-methylation of both pre-DMTs and DMTs; conversely, DmtMT1 recognizes the DKP rings, functioning before the assembly of the terpene moiety. Notably, both MTs display broad substrate promiscuity. Their combinatorial expression with the dmt1 genes in different Streptomyces strains successfully generated eight unnatural DMT analogs. Our results enriched the MT tool-box, setting the stage for exploring the structural diversity of DKP derivatives for drug development.

Keywords: Enzyme Engineering; Kinetic Chemistry; Structural Biology.