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  • The EMBO Journal (2000) 19, 1766 - 1776
  • doi:10.1093/emboj/19.8.1766

Structure and mechanism of the aberrant ba3-cytochrome c oxidase from Thermus thermophilus

Tewfik Soulimane1, Gerhard Buse1, Gleb P Bourenkov2, Hans D Bartunik2, Robert Huber3 and Manuel E Than3

  1. Rheinisch-Westfälische Technische Hochschule Aachen, Institut für Biochemie, Pauwelsstrasse 30, D-52057 Aachen, Germany
  2. Max-Planck-Arbeitsgruppen für Strukturelle Molekularbiologie, Gruppe Proteindynamik, MPG-ASMB, c/o DESY, Notkestrasse 85, D-22603 Hamburg Germany
  3. Max-Planck-Institut für Biochemie, Am Klopferspitz 18 A, 82152 Martinsried, Germany

Correspondence to:

Tewfik Soulimane, E-mail: tsoulimane@post.klinikum.rwth-aachen.de

Hans D BartunikManuel E Than, E-mail: than@biochem.mpg.de

Received 17 January 2000; Accepted 1 March 2000; Revised 29 February 2000

Cytochrome c oxidase is a respiratory enzyme catalysing the energy-conserving reduction of molecular oxygen to water. The crystal structure of the ba3-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 CuA to CuB. Specific features of the ba3-oxidase include an extended oxygen input channel, which leads directly to the active site, the presence of only one oxygen atom (O2-, OH- or H2O) 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.

  • Keywords:

    • ba3-cytochrome c oxidase,
    • MAD phasing,
    • membrane protein,
    • Thermus thermophilus,
    • X-ray structure