Trans/13-cis isomerization is essential for both the photocycle and proton pumping of bacteriorhodopsin

Journal Article · Mon Apr 01 00:00:00 EST 1985 · Biophys. J.; (United States)

DOI:https://doi.org/10.1016/S0006-3495(85)83944-8· OSTI ID:5267140

Chang, C H; Govindjee, R; Ebrey, T; Bagley, K A; Dollinger, G; Eisenstein, L; Marque, J; Roder, H; Vittitow, J; Fang, J M

An analogue of bacteriorhodopsin whose chromophore is based on all-trans retinal was studied. A five-membered ring was built around the 13-14 double bond so as to prohibit trans to 13-cis isomerization. No light-induced photochemical changes were seen, other than those due to a small amount (approximately 5%) of unbleached bacteriorhodopsin remaining in the apomembrane used for regeneration. The techniques used included flash photolysis at room and liquid nitrogen temperatures and Fourier-transform infrared difference spectroscopy. When the trans-fixed pigment was incorporated into phospholipid vesicles, no evidence of light-initiated proton pumping could be found. The results indicate that trans to 13-cis isomerization is essential for the photochemical transformation and function of bacteriorhodopsin.

• Research Organization: Univ. of Illinois at Urbana-Champaign, IL (United States)
• OSTI ID: 5267140
• Journal Information: Biophys. J.; (United States), Vol. 4
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
RHODOPSIN
MEMBRANE TRANSPORT
PHOTOLYSIS
CAROTENOIDS
ISOMERIZATION
PHOTOCHEMISTRY
PROTONS
SPECTROPHOTOMETRY
BARYONS
CHEMICAL REACTIONS
CHEMISTRY
DECOMPOSITION
ELEMENTARY PARTICLES
FERMIONS
HADRONS
HYDROCARBONS
NUCLEONS
ORGANIC COMPOUNDS
PHOTOCHEMICAL REACTIONS
PIGMENTS
PROTEINS
TERPENES
550500* - Metabolism