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Structure and mechanism of the aberrant ba 3 ‐cytochrome c oxidase from Thermus thermophilus
Author(s) -
Soulimane Tewfik,
Buse Gerhard,
Bourenkov Gleb P,
Bartunik Hans D,
Huber Robert,
Than Manuel E
Publication year - 2000
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/19.8.1766
Subject(s) - thermus thermophilus , cytochrome c oxidase , cytochrome c1 , biology , electron transport complex iv , active site , electron transfer , cytochrome b , coenzyme q – cytochrome c reductase , oxidoreductase , electron transport chain , cytochrome , oxidase test , cytochrome c , crystallography , stereochemistry , biochemistry , enzyme , chemistry , photochemistry , mitochondrion , mitochondrial dna , escherichia coli , gene
Cytochrome c oxidase is a respiratory enzyme catalysing the energy‐conserving reduction of molecular oxygen to water. The crystal structure of the ba 3 ‐cytochrome c oxidase from Thermus thermophilus has been determined to 2.4 Å resolution using multiple anomalous dispersion (MAD) phasing and led to the discovery of a novel subunit IIa. A structure‐based sequence alignment of this phylogenetically very distant oxidase with the other structurally known cytochrome oxidases leads to the identification of sequence motifs and residues that seem to be indispensable for the function of the haem copper oxidases, e.g. a new electron transfer pathway leading directly from Cu A to Cu B . Specific features of the ba 3 ‐oxidase include an extended oxygen input channel, which leads directly to the active site, the presence of only one oxygen atom (O 2− , OH − or H 2 O) as bridging ligand at the active site and the mainly hydrophobic character of the interactions that stabilize the electron transfer complex between this oxidase and its substrate cytochrome c . New aspects of the proton pumping mechanism could be identified.