Allosteric feedback inhibition of pyridoxine 5'-phosphate oxidase from Escherichia coli.

ABSTRACT: In Escherichia coli, the synthesis of pyridoxal 5'-phosphate (PLP), the catalytically active form of vitamin B₆, takes place through the so-called deoxyxylulose 5-phosphate-dependent pathway, whose last step is pyridoxine 5'-phosphate (PNP) oxidation to PLP, catalyzed by the FMN-dependent enzyme PNP oxidase (PNPOx). This enzyme plays a pivotal role in controlling intracellular homeostasis and bioavailability of PLP. PNPOx has been proposed to undergo product inhibition resulting from PLP binding at the active site. PLP has also been reported to bind tightly at a secondary site, apparently without causing PNPOx inhibition. The possible location of this secondary site has been indicated by crystallographic studies as two symmetric surface pockets present on the PNPOx homodi

SUBMITTER: Barile A 

PROVIDER: S-EPMC6816108 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature