Primary Citation of Related Structures: 3EY9, 3EYA
PubMed Abstract:
The thiamin- and flavin-dependent peripheral membrane enzyme pyruvate oxidase from E. coli catalyzes the oxidative decarboxylation of the central metabolite pyruvate to CO(2) and acetate. Concomitant reduction of the enzyme-bound flavin triggers membrane binding of the C terminus and shuttling of 2 electrons to ubiquinone 8, a membrane-bound mobile carrier of the electron transport chain ...
The thiamin- and flavin-dependent peripheral membrane enzyme pyruvate oxidase from E. coli catalyzes the oxidative decarboxylation of the central metabolite pyruvate to CO(2) and acetate. Concomitant reduction of the enzyme-bound flavin triggers membrane binding of the C terminus and shuttling of 2 electrons to ubiquinone 8, a membrane-bound mobile carrier of the electron transport chain. Binding to the membrane in vivo or limited proteolysis in vitro stimulate the catalytic proficiency by 2 orders of magnitude. The molecular mechanisms by which membrane binding and activation are governed have remained enigmatic. Here, we present the X-ray crystal structures of the full-length enzyme and a proteolytically activated truncation variant lacking the last 23 C-terminal residues inferred as important in membrane binding. In conjunction with spectroscopic results, the structural data pinpoint a conformational rearrangement upon activation that exposes the autoinhibitory C terminus, thereby freeing the active site. In the activated enzyme, Phe-465 swings into the active site and wires both cofactors for efficient electron transfer. The isolated C terminus, which has no intrinsic helix propensity, folds into a helical structure in the presence of micelles.
Organizational Affiliation:
Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Kurt-Mothes Strasse 3, D-06120 Halle/Saale, Germany.
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AA [auth B], BC [auth L], CC [auth L], DB [auth G], DC [auth L], EA [auth C], EB [auth G], EC [auth L], FA [auth C], FB [auth G], FC [auth L], JA [auth D], JB [auth H], KA [auth D], KB [auth H], LA [auth D], MA [auth D], NA [auth D], OA [auth D], OB [auth I], P [auth A], PA [auth D], PB [auth I], Q [auth A], R [auth A], S [auth A], T [auth A], TA [auth E], TB [auth J], U [auth A], UA [auth E], XB [auth K], Y [auth B], YA [auth F], Z [auth B], ZA [auth F]
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AC [auth L], CB [auth G], DA [auth C], IA [auth D], IB [auth H], NB [auth I], O [auth A], SA [auth E], SB [auth J], WB [auth K], X [auth B], XA [auth F]
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