| TITLE: | Glutamate-194 to cysteine mutation inhibits fast light-induced proton release in bacteriorhodopsin. |
|---|---|
| AUTHOR: | Balashov SP; Imasheva ES; Ebrey TG; Chen N; Menick DR; Crouch RK |
| AUTHOR AFFILIATION: | Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA. sbalasho@uiuc.edu |
| SOURCE: | Biochemistry 1997 Jul 22;36(29):8671-6 |
| NLM CIT. ID: | 97427802 |
| ABSTRACT: | Substitution of glutamic acid-194, a residue on the extracellular surface of bacteriorhodopsin, with a cysteine inhibits the fast light-induced proton release that normally is coupled with the deprotonation of the Schiff base during the L to M transition. Proton release in this mutant occurs at the very end of the photocycle and coincides with deprotonation of the primary proton acceptor, Asp-85, during the O to bR transition. the E194C mutation also results in a slowing down of the photocycle by about 1 order of magnitude as compared to the wild type and produces a strong effect on the pH dependence of dark adaptation that is interpreted as a drastic reduction or elimination of the coupling between the primary proton acceptor Asp-85 and the proton release group. These data indicate that Glu-194 is a critical component of the proton release complex in bacteriorhodopsin. |
| MAIN MESH SUBJECTS: | Bacteriorhodopsin/*METABOLISM
Cysteine/*GENETICS Glutamic Acid/*GENETICS *Light *Protons |
| ADDITIONAL MESH SUBJECTS: | Dark Adaptation
Halobacterium Hydrogen-Ion Concentration Kinetics Mutation Spectrophotometry, Atomic Absorption Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. |
| PUBLICATION TYPES: | JOURNAL ARTICLE |
| LANGUAGE: | Eng |
| REGISTRY NUMBERS: | 0 (Protons)
4371-52-2 (Cysteine) 53026-44-1 (Bacteriorhodopsin) 56-86-0 (Glutamic Acid) |
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