Biosynthetic Versatility and Coordinated Action of 5′-Deoxyadenosyl Radicals in Deazaflavin Biosynthesis Academic Article uri icon

abstract

  • Coenzyme F420 is a redox cofactor found in methanogens and in various actinobacteria. Despite the major biological importance of this cofactor, the biosynthesis of its deazaflavin core (8-hydroxy-5-deazaflavin, F(o)) is still poorly understood. F(o) synthase, the enzyme involved, is an unusual multidomain radical SAM enzyme that uses two separate 5'-deoxyadenosyl radicals to catalyze F(o) formation. In this paper, we report a detailed mechanistic study on this complex enzyme that led us to identify (1) the hydrogen atoms abstracted from the substrate by the two radical SAM domains, (2) the second tyrosine-derived product, (3) the reaction product of the CofH-catalyzed reaction, (4) the demonstration that this product is a substrate for CofG, and (5) a stereochemical study that is consistent with the formation of a p-hydroxybenzyl radical at the CofH active site. These results enable us to propose a mechanism for F(o) synthase and uncover a new catalytic motif in radical SAM enzymology involving the use of two 5'-deoxyadenosyl radicals to mediate the formation of a complex heterocycle.

published proceedings

  • J Am Chem Soc

altmetric score

  • 4

author list (cited authors)

  • Philmus, B., Decamps, L., Berteau, O., & Begley, T. P.

citation count

  • 34

complete list of authors

  • Philmus, Benjamin||Decamps, Laure||Berteau, Olivier||Begley, Tadhg P

publication date

  • April 2015