1cyx
QUINOL OXIDASE (PERIPLASMIC FRAGMENT OF SUBUNIT II WITH ENGINEERED CU-A BINDING SITE)(CYOA)
Structural highlights
FunctionCYOA_ECOLI Cytochrome bo(3) ubiquinol terminal oxidase is the component of the aerobic respiratory chain of E.coli that predominates when cells are grown at high aeration. Has proton pump activity across the membrane in addition to electron transfer, pumping 2 protons/electron.[1] [2] [3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCytochrome 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. 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[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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