title: The B12-Radical SAM Enzyme PoyC Catalyzes Valine Cβ-Methylation during Polytheonamide Biosynthesis.
abstract: Genomic and metagenomic investigations have recently led to the delineation of a novel class of natural products called ribosomally synthesized and post-translationally modified peptides (RiPPs). RiPPs are ubiquitous among living organisms and include pharmaceutically relevant compounds such as antibiotics and toxins. A prominent example is polytheonamide A, which exhibits numerous post-translational modifications, some of which were unknown in ribosomal peptides until recently. Among these post-translational modifications, C-methylations have been proposed to be catalyzed by two putative radical S-adenosylmethionine (rSAM) enzymes, PoyB and PoyC. Here we report the in vitro activity of PoyC, the first B12-dependent rSAM enzyme catalyzing peptide Cβ-methylation. We show that PoyC catalyzes the formation of S-adenosylhomocysteine and 5'-deoxyadenosine and the transfer of a methyl group to l-valine residue. In addition, we demonstrate for the first time that B12-rSAM enzymes have a tightly bound MeCbl cofactor that during catalysis transfers a methyl group originating from S-adenosyl-l-methionine. Collectively, our results shed new light on polytheonamide biosynthesis and the large and emerging family of B12-rSAM enzymes.
authors.affiliation: Micalis Institute, ChemSyBio, INRA, AgroParisTech, Université Paris-Saclay , F-78350 Jouy-en-Josas, France.
authors.forename: Aubérie
authors.initials: A
authors.lastname: Parent
authors.affiliation: Micalis Institute, ChemSyBio, INRA, AgroParisTech, Université Paris-Saclay , F-78350 Jouy-en-Josas, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Guillot
authors.affiliation: Micalis Institute, ChemSyBio, INRA, AgroParisTech, Université Paris-Saclay , F-78350 Jouy-en-Josas, France.
authors.forename: Alhosna
authors.initials: A
authors.lastname: Benjdia
authors.affiliation: Micalis Institute, ChemSyBio, INRA, AgroParisTech, Université Paris-Saclay , F-78350 Jouy-en-Josas, France.
authors.forename: Gwladys
authors.initials: G
authors.lastname: Chartier
authors.affiliation: INSERM U982, Université Rouen-Normandie , F-76821 Mont-Saint-Aignan, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Leprince
authors.affiliation: Micalis Institute, ChemSyBio, INRA, AgroParisTech, Université Paris-Saclay , F-78350 Jouy-en-Josas, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Berteau
mesh_terms: D055162:Biocatalysis; D005609:Free Radicals / Q000737:chemistry / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D008745:Methylation; D008780:Methyltransferases / Q000737:chemistry / Q000378:metabolism*; D008968:Molecular Conformation; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*; D012436:S-Adenosylmethionine / Q000737:chemistry / Q000378:metabolism*; D014805:Vitamin B 12 / Q000737:chemistry / Q000378:metabolism*
chemical_list: D005609:Free Radicals; D047908:Intracellular Signaling Peptides and Proteins; D011506:Proteins; C111717:polytheonamide B; D012436:S-Adenosylmethionine; D008780:Methyltransferases; D014805:Vitamin B 12