Chemical rescue and inhibition studies to determine the role of Arg301 in phosphite dehydrogenase.

ABSTRACT: Phosphite dehydrogenase (PTDH) catalyzes the NAD(+)-dependent oxidation of phosphite to phosphate. This reaction requires the deprotonation of a water nucleophile for attack on phosphite. A crystal structure was recently solved that identified Arg301 as a potential base given its proximity and orientation to the substrates and a water molecule within the active site. Mutants of this residue showed its importance for efficient catalysis, with about a 100-fold loss in k cat and substantially increased K m,phosphite for the Ala mutant (R301A). The 2.35 Å resolution crystal structure of the R301A mutant with NAD(+) bound shows that removal of the guanidine group renders the active site solvent exposed, suggesting the possibility of chemical rescue of activity. We show that the catalytic activi

SUBMITTER: Hung JE 

PROVIDER: S-EPMC3909101 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature