Primary Citation of Related Structures: 1CYW, 1CYX
PubMed Abstract:
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 ...
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.
Related Citations:
Crystallization and Preliminary X-Ray Analysis of the Periplasmic Fragment of Cyoa-A Subunit of the Escherichia Coli Cytochrome O Complex Van Der Oost, J., Musacchio, A., Pauptit, R.A., Ceska, T.A., Wierenga, R.K., Saraste, M. (1993) J Mol Biol 229: 794
Two Cysteines, Two Histidines and One Methionine are Ligands of a Binuclear Purple Copper Center Kelly, M., Lappalainen, P., Talbo, G., Haltia, T., Van Der Oost, J., Saraste, M. (1993) J Biol Chem 268: 16781
Restoration of a Lost Metal-Binding Site: Construction of Two Different Copper Sites Into a Subunit of the E. Coli Cytochrome O Quinol Oxidase Complex Van Der Oost, J., Lappalainen, P., Musacchio, A., Warne, A., Lemieux, L., Rumbley, J., Gennis, R.B., Aasa, R., Pascher, T., Malmstrom, B.M., Saraste, M. (1992) EMBO J 11: 3209
Organizational Affiliation:
European Molecular Biology Laboratory, Heidelberg, Germany.
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