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MOLECULAR ASPECTS OF LIGHT‐INDUCED UPTAKE AND RELEASE OF PROTONS BY PURPLE MEMBRANES
Author(s) -
Packer Lester,
Quintanilha Alexandre T.,
Carmeli Chanoch,
Sullivan Paul D.,
Scherrer Peter,
Tristram Stephanie,
Herz Jeffrey,
Pfeifhofer Albert,
Mehlhorn Rolf J.
Publication year - 1981
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1981.tb05462.x
Subject(s) - protonation , bacteriorhodopsin , chemistry , amino acid , membrane , side chain , lysine , proton transport , aromatic amino acids , proton , kinetics , arginine , biophysics , tyrosine , chromosomal translocation , molecular dynamics , photochemistry , biochemistry , ion , computational chemistry , organic chemistry , biology , physics , quantum mechanics , gene , polymer
— The precise molecular description of the time dependent steps in the uptake, translocation and release of protons by bacteriorhodopsin following photon absorption requires information on the time resolved changes in protonation of the side chains of specific amino acid residues and the correlation of these changes with photocycle kinetics. Thus far, the use of chemical modification to probe the role of amino acid side chains in this process has proven of value in demonstrating a role for tyrosine residues in release and uptake of protons associated with early and later stages (before and after M 412 formation) of the photocycle. In addition, it has demonstrated the essential role of ionic interactions between negatively charged carboxyl groups and positively charged guanidinium groups of arginine, and amino groups of lysine. The transmembrane regulatory effect of Δμ H + on the M 412 species of the photocycle provides additional evidence for the participation of reversible protonation of amino acid side chains at the surfaces of the purple membrane in the mechanism of proton translocation. Thus, our studies relate molecular events of proton translocation to the bioenergetics of the purple membrane.