Gene identification and structural characterization of the pyridoxal 5'-phosphate degradative protein 3-hydroxy-2-methylpyridine-4,5-dicarboxylate decarboxylase from mesorhizobium loti MAFF303099.

ABSTRACT: The function of the mlr6791 gene from Mesorhizobium loti MAFF303099 has been identified. This gene encodes 3-hydroxy-2-methylpyridine-4,5-dicarboxylate decarboxylase (HMPDdc), an enzyme involved in the catabolism of pyridoxal 5'-phosphate (Vitamin B6). This enzyme was overexpressed in Escherichia coli and characterized. HMPDdc is a 26 kDa protein that catalyzes the decarboxylation of 3-hydroxy-2-methylpyridine-4,5-dicarboxylate to 3-hydroxy-2-methylpyridine-5-carboxylate. The KM and kcat were found to be 366 microM and 0.6 s-1, respectively. The structure of this enzyme was determined at 1.9 A resolution using SAD phasing and belongs to the class II aldolase/adducin superfamily. While the decarboxylation of hydroxy-substituted benzene rings is a common motif in biosynthesis, the mechanism

SUBMITTER: Mukherjee T 

PROVIDER: S-EPMC2587025 | biostudies-literature | 2007 Nov

REPOSITORIES: biostudies-literature