3EY9

Structural basis for membrane binding and catalytic activation of the peripheral membrane enzyme pyruvate oxidase from Escherichia coli

Summary for 3EY9

• Entry DOI: 10.2210/pdb3ey9/pdb
• Related: 1POW 3EYA
• Descriptor: Pyruvate dehydrogenase [cytochrome], THIAMINE DIPHOSPHATE, FLAVIN-ADENINE DINUCLEOTIDE, ... (5 entities in total)
• Functional Keywords: pyruvate oxidase, membrane-associated flavoprotein dehydrogenase, interactions with lipids, cell membrane, fad, flavoprotein, lipid-binding, magnesium, membrane, oxidoreductase, thiamine pyrophosphate
• Biological source: Escherichia coli
• Cellular location: Cell membrane; Peripheral membrane protein: P07003
• Total number of polymer chains: 2
• Total formula weight: 126828.95

Authors

Neumann, P.,Weidner, A.,Pech, A.,Stubbs, M.T.,Tittmann, K. (deposition date: 2008-10-20, release date: 2008-11-04, Last modification date: 2023-11-01)

Primary citation

Neumann, P.,Weidner, A.,Pech, A.,Stubbs, M.T.,Tittmann, K.
Structural basis for membrane binding and catalytic activation of the peripheral membrane enzyme pyruvate oxidase from Escherichia coli.
Proc.Natl.Acad.Sci.USA, 105:17390-17395, 2008

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. 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.

PubMed: 18988747
DOI: 10.1073/pnas.0805027105

Experimental method

X-RAY DIFFRACTION (2.9 Å)