L-tyrosine-bound ThiH structure reveals C–C bond break differences within radical SAM aromatic amino acid lyases

Abstract

ThiH is a radical SAM L-tyrosine lyase involved in the biosynthesis of the thiazole ring of vitamin B1. Here, the authors report the crystal structure of ThiH in complex with its L-tyrosine substrate, revealing an unexpected protonation state and tunneling effect that lowers the reaction energy barrier.