Bacteriorhodopsin-like proteins of eubacteria and fungi: the extent of conservation of the haloarchaeal proton-pumping mechanism.
A stereotypical image of a retinal-binding proton pump derived from extensive studies of halobacterial ion-transporting and sensory rhodopsins is a fast-cycling protein which possesses two strategically placed carboxylic acids serving as proton donor and acceptor for the retinal Schiff base. We review recent biophysical and bioinformatic data on the novel eubacterial and eucaryotic rhodopsins to analyze the extent of conservation of the haloarchaeal mechanism of transmembrane proton transport. We show that only the most essential elements of the haloarchaeal proton-pumping machinery are conserved universally, and that a mere presence of these elements in primary structures does not guarantee the proton-pumping ability.
Brown
Leonid S
LS
Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1, Canada. leonid@physics.uoguelph.ca
Jung
Kwang-Hwan
KH
D000595:Amino Acid Sequence; D001105:Archaea / Q000737:chemistry*; D001419:Bacteria / Q000737:chemistry*; D001436:Bacteriorhodopsins / Q000737:chemistry*; D005658:Fungi / Q000737:chemistry*; D008969:Molecular Sequence Data; D017494:Proton Pumps / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid
D017494:Proton Pumps; D001436:Bacteriorhodopsins