Anaerobic 5-Hydroxybenzimidazole Formation from Aminoimidazole Ribotide: An Unanticipated Intersection of Thiamin and Vitamin B Biosynthesis. Academic Article uri icon


  • Comparative genomics of the bacterial thiamin pyrimidine synthase (thiC) revealed a paralogue of thiC (bzaF) clustered with anaerobic vitamin B12 biosynthetic genes. Here we demonstrate that BzaF is a radical S-adenosylmethionine enzyme that catalyzes the remarkable conversion of aminoimidazole ribotide (AIR) to 5-hydroxybenzimidazole (5-HBI). We identify the origin of key product atoms and propose a reaction mechanism. These studies represent the first step in solving a long-standing problem in anaerobic vitamin B12 assembly and reveal an unanticipated intersection of thiamin and vitamin B12 biosynthesis.

published proceedings

  • J Am Chem Soc

altmetric score

  • 3.5

author list (cited authors)

  • Mehta, A. P., Abdelwahed, S. H., Fenwick, M. K., Hazra, A. B., Taga, M. E., Zhang, Y., Ealick, S. E., & Begley, T. P.

citation count

  • 22

complete list of authors

  • Mehta, Angad P||Abdelwahed, Sameh H||Fenwick, Michael K||Hazra, Amrita B||Taga, Michiko E||Zhang, Yang||Ealick, Steven E||Begley, Tadhg P

publication date

  • August 2015