Anaerobic 5-Hydroxybenzimidazole Formation from Aminoimidazole Ribotide: An Unanticipated Intersection of Thiamin and Vitamin B12 Biosynthesis

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• 作者：Angad P. Mehta ; Sameh H. Abdelwahed ; Michael K. Fenwick ; Amrita B. Hazra ; Michiko E. Taga ; Yang Zhang ; Steven E. Ealick ; Tadhg P. Begley
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：August 26, 2015
• 年：2015
• 卷：137
• 期：33
• 页码：10444-10447
• 全文大小：362K
• ISSN：1520-5126

文摘

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.