Characterization of metal binding of bifunctional kinase/phosphatase AceK and implication in activity modulation.

ABSTRACT: A unique bifunctional enzyme, isocitrate dehydrogenase kinase/phosphatase (AceK) regulates isocitrate dehydrogenase (IDH) by phosphorylation and dephosphorylation in response to nutrient availability. Herein we report the crystal structure of AceK in complex with ADP and Mn²⁺ ions. Although the overall structure is similar to the previously reported structures which contain only one Mg²⁺ ion, surprisingly, two Mn²⁺ ions are found in the catalytic center of the AceK-Mn²⁺ structure. Our enzymatic assays demonstrate that AceK-Mn²⁺ showed higher phosphatase activity than AceK-Mg²⁺, whereas the kinase activity was relatively unaffected. We created mutants of AceK for all metal-coordinating residues. The phosphatase activities of

SUBMITTER: Zhang X 

PROVIDER: S-EPMC6591243 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature