GenK-catalyzed C-6' methylation in the biosynthesis of gentamicin: isolation and characterization of a cobalamin-dependent radical SAM enzyme.

ABSTRACT: The existence of cobalamin (Cbl)-dependent enzymes that are members of the radical S-adenosyl-l-methionine (SAM) superfamily was previously predicted on the basis of bioinformatic analysis. A number of these are Cbl-dependent methyltransferases, but the details surrounding their reaction mechanisms have remained unclear. In this report we demonstrate the in vitro activity of GenK, a Cbl-dependent radical SAM enzyme that methylates an unactivated sp(3) carbon during the biosynthesis of gentamicin, an aminoglycoside antibiotic. Experiments to investigate the stoichiometry of the GenK reaction revealed that 1 equiv each of 5'-deoxyadenosine and S-adenosyl-homocysteine are produced for each methylation reaction catalyzed by GenK. Furthermore, isotope-labeling experiments demonstrate that the S

SUBMITTER: Kim HJ 

PROVIDER: S-EPMC3796153 | biostudies-literature | 2013 Jun

REPOSITORIES: biostudies-literature