Feryel Soualmia, Mickael V Cherrier, Timothée Chauviré, Mickaël Mauger, Philip Tatham, Alain Guillot, Xavier Guinchard, Lydie Martin, Patricia Amara, Jean-Marie Mouesca, Meriem Daghmoum, Alhosna Benjdia, Serge Gambarelli, Olivier Berteau, Yvain Nicolet
PylB is a radical S -adenosyl-l-methionine (SAM) enzyme predicted to convert l-lysine into (3 R )-3-methyl-d-ornithine, a precursor in the biosynthesis of the 20 s proteogenic amino acid pyrrolysine. This protein highly resembles that of the radical SAM tyrosine and tryptophan lyases, which activate their substrate by abstracting a H atom from the amino-nitrogen position. Here, combining in vitro assays, analytical methods, electron paramagnetic resonance spectroscopy, and theoretical methods, we demonstrated that instead, PylB activates its substrate by abstracting a H atom from the Cγ position of l-lysine to afford the radical-based β-scission...
March 1, 2024: Journal of the American Chemical Society