Download MendeleyO-Methyltransferase-Mediated Incorporation of a beta-Amino Acid in Lanthipeptides.
Acedo, J.Z., Bothwell, I.R., An, L., Trouth, A., Frazier, C., van der Donk, W.A.(2019) J Am Chem Soc 141: 16790-16801
- PubMed: 31568727
- DOI: https://doi.org/10.1021/jacs.9b07396
- Primary Citation of Related Structures:
6PQF, 6PQG - PubMed Abstract:
Lanthipeptides represent a large class of cyclic natural products defined by the presence of lanthionine (Lan) and methyllanthionine (MeLan) cross-links. With the advances in DNA sequencing technologies and genome mining tools, new biosynthetic enzymes capable of installing unusual structural features are continuously being discovered. In this study, we investigated an O -methyltransferase that is a member of the most prominent auxiliary enzyme family associated with class I lanthipeptide biosynthetic gene clusters. Despite the prevalence of these enzymes, their function has not been established. Herein, we demonstrate that the O -methyltransferase OlvS A encoded in the olv gene cluster from Streptomyces olivaceus NRRL B-3009 catalyzes the rearrangement of a highly conserved aspartate residue to a β-amino acid, isoaspartate, in the lanthipeptide OlvA(BCS A ). We elucidated the NMR solution structure of the GluC-digested peptide, OlvA(BCS A ) GluC , which revealed a unique ring topology comprising four interlocking rings and positions the isoaspartate residue in a solvent exposed loop that is stabilized by a MeLan ring. Gas chromatography-mass spectrometry analysis further indicated that OlvA(BCS A ) contains two dl-MeLan rings and two Lan rings with an unusual ll-stereochemistry. Lastly, in vitro reconstitution of OlvS A activity showed that it is a leader peptide-independent and S -adenosyl methionine-dependent O -methyltransferase that mediates the conversion of a highly conserved aspartate residue in a cyclic substrate into a succinimide, which is hydrolyzed to generate an Asp or isoAsp containing peptide. This overall transformation converts an α-amino acid into a β-amino acid in a ribosomally synthesized peptide, via an electrophilic intermediate that may be the intended product.
Organizational Affiliation:
Department of Chemistry and Howard Hughes Medical Institute , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States.
