Structural and biochemical studies on the regulation of biotin carboxylase by substrate inhibition and dimerization.

ABSTRACT: Biotin carboxylase (BC) activity is shared among biotin-dependent carboxylases and catalyzes the Mg-ATP-dependent carboxylation of biotin using bicarbonate as the CO(2) donor. BC has been studied extensively over the years by structural, kinetic, and mutagenesis analyses. Here we report three new crystal structures of Escherichia coli BC at up to 1.9 Å resolution, complexed with different ligands. Two structures are wild-type BC in complex with two ADP molecules and two Ca(2+) ions or two ADP molecules and one Mg(2+) ion. One ADP molecule is in the position normally taken by the ATP substrate, whereas the other ADP molecule occupies the binding sites of bicarbonate and biotin. One Ca(2+) ion and the Mg(2+) ion are associated with the ADP molecule in the active site, and the other Ca(2+) io

SUBMITTER: Chou CY 

PROVIDER: S-EPMC3129220 | biostudies-literature | 2011 Jul

REPOSITORIES: biostudies-literature