The membrane-extrinsic domain of cytochrome b(558/566) from the archaeon Sulfolobus acidocaldarius performs pivoting movements with respect to the membrane surface.
The orientation of the membrane-attached cytochrome b(558/566)-haem with respect to the membrane was determined by electron paramagnetic resonance spectroscopy on two-dimensionally ordered oxidised membrane fragments from Sulfolobus acidocaldarius. Unlike the other redox centres in the membrane, the cytochrome b(558/566)-haem was found to cover a range of orientations between 25 degrees and 90 degrees. The described results are reminiscent of those obtained on the Rieske cluster of bc complexes and indicate that the membrane-extrinsic domain of cytochrome b(558/566) can perform pivoting motion between two extreme positions. Such a conformational flexibility is likely to play a role in electron transfer with its redox partners.
Schoepp-Cothenet
B
B
Laboratoire de Bioenérgétique et Ingénierie des Protéines, CNRS, UPR 9036, Institut de Biologie Structurale et Microbiologie, Marseille, France. schoepp@ibsm.cnrs-mrs.fr
Schütz
M
M
Baymann
F
F
Brugna
M
M
Nitschke
W
W
Myllykallio
H
H
Schmidt
C
C
D000595:Amino Acid Sequence; D002462:Cell Membrane / Q000737:chemistry; D003573:Cytochrome b Group / Q000737:chemistry* / Q000235:genetics; D004578:Electron Spin Resonance Spectroscopy; D004579:Electron Transport; D008969:Molecular Sequence Data; D019255:NADPH Oxidases; D010084:Oxidation-Reduction; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D016944:Sulfolobus / Q000737:chemistry / Q000235:genetics; D016945:Sulfolobus acidocaldarius / Q000737:chemistry* / Q000235:genetics
D003573:Cytochrome b Group; C020730:cytochrome b566; C036888:cytochrome b558; D019255:NADPH Oxidases