Structure-function studies on bacteriorhodopsin. X. Individual substitutions of arginine residues by glutamine affect chromophore formation, photocycle, and proton translocation
- Massachusetts Institute of Technology, Cambridge (USA)
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----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.
- OSTI ID:
- 5479297
- Journal Information:
- Journal of Biological Chemistry; (USA), Vol. 264:24; Other Information: Databank sent to: GENBANK/J04983; EMBL/J04983; ISSN 0021-9258
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
RHODOPSIN
STRUCTURE-ACTIVITY RELATIONSHIPS
AMINO ACID SEQUENCE
ARGININE
BACTERIA
GLUTAMINE
MEMBRANE PROTEINS
MUTATIONS
PHENOTYPE
PHOTOSYNTHESIS
PROTONS
TRANSLOCATION
AMIDES
AMINO ACIDS
BARYONS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
ELEMENTARY PARTICLES
FERMIONS
HADRONS
MICROORGANISMS
MOLECULAR STRUCTURE
NUCLEONS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PIGMENTS
PROTEINS
SYNTHESIS
550200* - Biochemistry