Proton transfers in the bacteriorhodopsin photocycle
نویسندگان
چکیده
منابع مشابه
A correlation between proton pumping and the bacteriorhodopsin photocycle.
In an attempt to establish a relationship between proton pumping and the photocycle intermediates of bacteriorhodopsin, we have studied the effects of pH and temperature on flash-induced proton pumping and the photointermediates O640 and M412. The relative quantum yield of flash-induced proton pumping is both pH and temperature dependent. It is high in the acid pH range and at low temperatures ...
متن کاملProton affinity changes driving unidirectional proton transport in the bacteriorhodopsin photocycle.
Bacteriorhodopsin is the smallest autonomous light-driven proton pump. Proposals as to how it achieves the directionality of its trans-membrane proton transport fall into two categories: accessibility-switch models in which proton transfer pathways in different parts of the molecule are opened and closed during the photocycle, and affinity-switch models, which focus on changes in proton affinit...
متن کاملCalculation of proton transfers in Bacteriorhodopsin bR and M intermediates.
Residue ionization states were calculated in nine crystal structures of bacteriorhodopsin trapped in bR, early M, and late M states by multiconformation continuum electrostatics. This combines continuum electrostatics and molecular mechanics, deriving equilibrium distributions of ionization states and polar residue and water positions. The three central cluster groups [retinal Schiff base (SB),...
متن کاملProtein conformational changes in the bacteriorhodopsin photocycle.
We report a comprehensive electron crystallographic analysis of conformational changes in the photocycle of wild-type bacteriorhodopsin and in a variety of mutant proteins with kinetic defects in the photocycle. Specific intermediates that accumulate in the late stages of the photocycle of wild-type bacteriorhodopsin, the single mutants D38R, D96N, D96G, T46V, L93A and F219L, and the triple mut...
متن کاملStructure changes upon deprotonation of the proton release group in the bacteriorhodopsin photocycle.
In the photocycle of bacteriorhodopsin at pH 7, a proton is ejected to the extracellular medium during the protonation of Asp-85 upon formation of the M intermediate. The group that releases the ejected proton does not become reprotonated until the prephotolysis state is restored from the N and O intermediates. In contrast, at acidic pH, this proton release group remains protonated to the end o...
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ژورنال
عنوان ژورنال: Biochimica et Biophysica Acta (BBA) - Bioenergetics
سال: 2006
ISSN: 0005-2728
DOI: 10.1016/j.bbabio.2005.11.003