required, binding structure analysis. The rearrangement of FAD between the out and in positions is required in the catalytic mechanism comprised of reductive and oxidative reactions, which are shared among NahG and other flavin-dependent monooxygenases
required, contribution of individual pieces of the FAD cofactor to the observed enzymatic activity for turnover of the whole cofactor. Comparison of the kinetic parameters and products for the NahG-catalyzed reactions of FMN and riboflavin cofactor fragments reveal that the adenosine monophosphate (AMP) and ribitol phosphate pieces of FAD act to anchor the flavin to the enzyme and to direct the partitioning of the C(4a)-hydroperoxyflavin reaction intermediate towards hydroxylation of salicylate. The addition of AMP or ribitol phosphate pieces to solutions of the truncated flavins results in a partial restoration of the enzymatic activity lost upon truncation of FAD, and the pieces direct the reaction of the C(4a)-hydroperoxyflavin intermediate towards hydroxylation of salicylate