Mechanistic and structural analyses of the roles of Arg409 and Asp402 in the reaction of the flavoprotein nitroalkane oxidase.

ABSTRACT: The flavoprotein nitroalkane oxidase (NAO) catalyzes the oxidation of primary and secondary nitroalkanes to the corresponding aldehydes and ketones. The enzyme is a homologue of acyl-CoA dehydrogenase. Asp402 in NAO has been proposed to be the active site base responsible for removing the substrate proton in the first catalytic step; structurally it corresponds to the glutamate which acts as the base in medium chain acyl-CoA dehydrogenase. In the active site of NAO, the carboxylate of Asp402 forms an ionic interaction with the side chain of Arg409. The R409K enzyme has now been characterized kinetically and structurally. The mutation results in a decrease in the rate constant for proton abstraction of 100-fold. Analysis of the three-dimensional structure of the R409K enzyme, determined by

SUBMITTER: Fitzpatrick PF 

PROVIDER: S-EPMC2526231 | biostudies-literature | 2007 Dec

REPOSITORIES: biostudies-literature