Structural and Functional Analyses of the Tridomain‐Nonribosomal Peptide Synthetase FmoA3 for 4‐Methyloxazoline Ring Formation. (17th May 2021)

• Record Type: Journal Article
• Authors: Katsuyama, Yohei; Sone, Kaoru; Harada, Ayaka; Kawai, Seiji; Urano, Naoki; Adachi, Naruhiko; Moriya, Toshio; Kawasaki, Masato; Shin‐ya, Kazuo; Senda, Toshiya; Ohnishi, Yasuo
• Is Part Of: Angewandte Chemie. Volume 133:Number 26(2021)
• Page Start: 14675
• Page End: 14683
• Publication Date: 2021-05-17
• Subjects: cryogenic electron microscopy -- heterocyclization -- nonribosomal peptide synthetase -- X-ray crystallography; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202102760
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: Nonribosomal peptide synthetases (NRPSs) are attractive targets for bioengineering to generate useful peptides. FmoA3 is a single modular NRPS composed of heterocyclization (Cy), adenylation (A), and peptidyl carrier protein (PCP) domains. It uses α‐methyl‐l ‐serine to synthesize a 4‐methyloxazoline ring, probably with another Cy domain in the preceding module FmoA2. Here, we determined the head‐to‐tail homodimeric structures of FmoA3 by X‐ray crystallography ( apo ‐form, with adenylyl‐imidodiphosphate and α‐methyl‐l ‐seryl‐AMP) and cryogenic electron microscopy single particle analysis, and performed site‐directed mutagenesis experiments. The data revealed that α‐methyl‐l ‐serine can be accommodated in the active site because of the extra space around Ala688. The Cy domains of FmoA2 and FmoA3 catalyze peptide bond formation and heterocyclization, respectively. FmoA3's Cy domain seems to lose its donor PCP binding activity. The collective data support a proposed catalytic cycle of FmoA3. Abstract : The dimeric structure of the nonribosomal peptide synthetase (NRPS), FmoA3 which consists of Cy‐A‐PCP domains, was solved by two strategies, X‐ray crystallography and cryogenic electron microscopy. The molecular basis of the α, α‐disubstituted amino acid recognition mechanism of the A domain of FmoA3 was proposed. The Cy domain of FmoA3 was expected to lose peptide bond formation activity by eliminating its ability to bind with a donor PCP.