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The photochemical reaction cycle of retinal reconstituted bacteriorhodopsin

Paper ID Volume ID Publish Year Pages File Format Full-Text
30570 44487 2006 5 PDF Available
Title
The photochemical reaction cycle of retinal reconstituted bacteriorhodopsin
Abstract

The function of three types of bacteriorhodopsins was compared: the wild-type, the bleached and retinal reconstituted and retinal deficient bacteriorhodopsin after retinal addition. The apparent pKa of the proton acceptor group for the bleached BR and retinal deficient BR shifted toward higher pH values compared to the wild-type BR. Fitting the photocycle model to the absorption kinetic signals for all three proteins showed the existence of the same intermediates, but the time-dependent concentration of the intermediates was different. Although measurements were made at pH 7, the absorption kinetics and photoelectric signals in both retinal reconstituted samples acted as wild-type bacteriorhodopsin at significantly higher pH. Below pH 3 the retinal deficient and reconstituted sample bleached. These results suggested that the added retinal was not able to rebind in the same position in the protein as in native bacteriorhodopsin. This points out that care should be taken, when bleached bacteriorhodopsin is reconstituted with different retinal analogs.

Keywords
Retinal protein; Photocycle; Absorption kinetics; Retinal reconstitution
First Page Preview
The photochemical reaction cycle of retinal reconstituted bacteriorhodopsin
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 85, Issue 2, 1 November 2006, Pages 140–144
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering