Structure-function studies on bacteriorhodopsin. X. Individual substitutions of arginine residues by glutamine affect chromophore formation, photocycle, and proton translocation

摘要: We have individually replaced all 7 of the arginine residues in bacteriorhodopsin by glutamine. The mutants with substitutions at positions 7, 164, 175, and 225 showed essentially wild-type phenotype regard to chromophore regeneration, lambda max, proton pumping, although mutant Arg-175----Gln decreased rate regeneration. Glutamine Arg-82, -134, -227 affected pumping ability, caused specific alterations photocycle. Finally, electrostatic interactions are proposed between Arg-82 -227, carboxylic acid helices C G, which regulate purple blue transition transfers during