• 25 August 1989
    • journal article
    • research article
    • Vol. 264  (24) , 14202-14208
Abstract
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 the wild-type phenotype in regard to chromophore regeneration, chromophore .lambda.max, and proton pumping, although the mutant Arg-175 .fwdarw. Gln showed decreased rate of chromophore regeneration. Glutamine substitutions of Arg-82, -134, and -227 affected proton pumping ability, and caused specific alterations in the bacteriorhodopsin photocycle. Finally, electrostatic interactions are proposed between Arg-82 and -227, and specific carboxylic acid residues in helices C and G, which regulate the purple to blue transition and proton transfers during the photocycle.