The photochemical reaction cycle of retinal reconstituted bacteriorhodopsin

Klára Magyari, Zoltán Bálint, Viorica Simon, György Váró

Research output: Contribution to journalArticle

4 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)140-144
Number of pages5
JournalJournal of Photochemistry and Photobiology B: Biology
Volume85
Issue number2
DOIs
Publication statusPublished - Nov 1 2006

Keywords

  • Absorption kinetics
  • Photocycle
  • Retinal protein
  • Retinal reconstitution

ASJC Scopus subject areas

  • Radiation
  • Radiological and Ultrasound Technology
  • Biophysics
  • Radiology Nuclear Medicine and imaging

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