Conformational changes on substrate binding revealed by structures of Methylobacterium extorquens malate dehydrogenase.

ABSTRACT: Three high-resolution X-ray crystal structures of malate dehydrogenase (MDH; EC 1.1.1.37) from the methylotroph Methylobacterium extorquens AM1 are presented. By comparing the structures of apo MDH, a binary complex of MDH and NAD⁺, and a ternary complex of MDH and oxaloacetate with ADP-ribose occupying the pyridine nucleotide-binding site, conformational changes associated with the formation of the catalytic complex were characterized. While the substrate-binding site is accessible in the enzyme resting state or NAD⁺-bound forms, the substrate-bound form exhibits a closed conformation. This conformational change involves the transition of an α-helix to a 3₁₀-helix, which causes the adjacent loop to close the active site following coenzyme and substrate bin

SUBMITTER: Gonzalez JM 

PROVIDER: S-EPMC6168771 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature