title: Photochemistry of monomethylated and permethylated bacteriorhodopsin.
abstract: Methylation of the nonactive site lysines of bacteriorhodopsin to form permethylated bacteriorhodopsin does not interfere with the formation of the short wavelength intermediate M412 or light-induced proton release/uptake. The absorption spectrum is similar to that of the native bacteriorhodopsin. However, additional monomethylation of the active site lysine of bacteriorhodopsin causes a red shift of the absorption maximum from 568 nm in light-adapted bacteriorhodopsin [BR] to 630 nm. The photochemistry of active-site methylated BR does not proceed beyond the L-photointermediate. In particular, the photointermediate corresponding to M412 does not form, and there is no proton pumping. Moreover, there is no tyrosine deprotonation. Thus, the formation of an M-type photointermediate is required for proton pumping by BR.
authors.affiliation: Department of Physiology, University of Illinois, Urbana 61801.
authors.forename: R
authors.initials: R
authors.lastname: Govindjee
authors.forename: Z
authors.initials: Z
authors.lastname: Dancshazy
authors.forename: T G
authors.initials: TG
authors.lastname: Ebrey
authors.forename: C
authors.initials: C
authors.lastname: Longstaff
authors.forename: R R
authors.initials: RR
authors.lastname: Rando
mesh_terms: D001436:Bacteriorhodopsins / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000528:radiation effects; D006217:Halobacterium / Q000378:metabolism; D007700:Kinetics; D007834:Lasers; D008745:Methylation; D010777:Photochemistry; D013053:Spectrophotometry
chemical_list: D001436:Bacteriorhodopsins