A bicarbonate cofactor modulates 1,4-dihydroxy-2-naphthoyl-coenzyme a synthase in menaquinone biosynthesis of Escherichia coli.

ABSTRACT: 1,4-Dihydroxy-2-naphthoyl coenzyme A (DHNA-CoA) synthase is a typical crotonase-fold protein catalyzing an intramolecular Claisen condensation in the menaquinone biosynthetic pathway. We have characterized this enzyme from Escherichia coli and found that it is activated by bicarbonate in a concentration-dependent manner. The bicarbonate binding site has been identified in the crystal structure of a virtually identical ortholog (96.8% sequence identity) from Salmonella typhimurium through comparison with a bicarbonate-insensitive orthologue. Kinetic properties of the enzyme and its site-directed mutants of the bicarbonate binding site indicate that the exogenous bicarbonate anion is essential to the enzyme activity. With this essential catalytic role, the simple bicarbonate anion is an enzy

SUBMITTER: Jiang M 

PROVIDER: S-EPMC2943303 | biostudies-literature | 2010 Sep

REPOSITORIES: biostudies-literature