1cyw
QUINOL OXIDASE (PERIPLASMIC FRAGMENT OF SUBUNIT II) (CYOA)
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OverviewOverview
Cytochrome oxidase is a membrane protein complex that catalyzes reduction, of molecular oxygen to water and utilizes the free energy of this reaction, to generate a transmembrane proton gradient during respiration. The, electron entry site in subunit II is a mixed-valence dinuclear copper, center in enzymes that oxidize cytochrome c. This center has been lost, during the evolution of the quinoloxidizing branch of cytochrome oxidases, but can be restored by engineering. Herein we describe the crystal, structures of the periplasmic fragment from the wild-type subunit II, (CyoA) of Escherichia coli quinol oxidase at 2.5-A resolution and of the, mutant with the engineered dinuclear copper center (purple CyoA) at 2.3-A, resolution. CyoA is folded as an 11-stranded mostly antiparallel, beta-sandwich followed by three alpha-helices. The dinuclear copper center, is located at the loops between strands beta 5-beta 6 and beta 9-beta 10., The two coppers are at a 2.5-A distance and symmetrically coordinated to, the main ligands that are two bridging cysteines and two terminal, histidines. The residues that are distinct in cytochrome c and quinol, oxidases are around the dinuclear copper center. Structural comparison, suggests a common ancestry for subunit II of cytochrome oxidase and blue, copper-binding proteins.
About this StructureAbout this Structure
1CYW is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of the membrane-exposed domain from a respiratory quinol oxidase complex with an engineered dinuclear copper center., Wilmanns M, Lappalainen P, Kelly M, Sauer-Eriksson E, Saraste M, Proc Natl Acad Sci U S A. 1995 Dec 19;92(26):11955-9. PMID:8618822
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