1EHK: Crystal Structure of the Aberrant Ba3-cytochrome-c Oxidase From Thermus Thermophilus

Citation:
Abstract
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 A 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.
PDB ID: 1EHKDownload
MMDB ID: 15645
PDB Deposition Date: 2000/2/21
Updated in MMDB: 2012/11 
Experimental Method:
x-ray diffraction
Resolution: 2.4  Å
Source Organism:
Similar Structures:
Biological Unit for 1EHK: trimeric; determined by author and by software (PISA)
Molecular Components in 1EHK
Label Count Molecule
Proteins (3 molecules)
1
Ba3-type Cytochrome-c Oxidase
Molecule annotation
1
Ba3-type Cytochrome-c Oxidase
Molecule annotation
1
Ba3-type Cytochrome-c Oxidase
Molecule annotation
Chemicals (7 molecules)
1
3
2
1
3
1
4
1
5
1
* Click molecule labels to explore molecular sequence information.

Citing MMDB
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