Bacteriorhodopsin's L sub 550 intermediate contains a C14-C15 s-trans-retinal chromophore

Journal Article · Thu Mar 31 23:00:00 EST 1988 · Proceedings of the National Academy of Sciences of the United States of America; (USA)

DOI:https://doi.org/10.1073/pnas.85.7.2156· OSTI ID:6891634

Fodor, S P.A.; Pollard, W T; Mathies, R A ^[1]; Gebhard, R; Van Den Berg, E M.M.; Lugtenburg, J ^[2]

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1. Univ. of California, Berkeley (USA)
2. Leiden Univ. (Netherlands)

Conformational changes of the retinal chromophore about the C14-C15 bond in bacteriorhodopsin (BR) have been proposed in models for the mechanism of light-driven proton transport. To determine the C14-C15 conformation in BR's L{sub 550} intermediate, the authors have examined the resonance Raman spectra of BR derivatives regenerated with retinal deuterated at the 14 and 15 positions. Vibrational calculations show that the C14-{sup 2}H and C15-{sup 2}H rocking modes form symmetric (A) and antisymmetric (B) combinations in (14,15-{sup 2}H)retinal chromophores. When there is a trans conformation about the single bond between C14 and C15 (14-s-trans), a small frequency separation or splitting is observed between the A and B modes. In addition, the monodeuterium rock should appear at an unusually low frequency in the 14-{sup 2}H-labeled 14-s-cis molecules. These patterns are insensitive to computational details. Time-resolved resonance Raman spectra were obtained of BR's L{sub 550} intermediate regenerated with (14-{sup 2}H)-, (15-{sup 2}H)- and (14,15-{sup 2}H)retinal. These results show that L{sub 550} contains a 14-s-trans chromophore and suggest that only 14-2-trans structures are involved in the proton pumping photocycle of BR.

• OSTI ID: 6891634
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (USA), Journal Name: Proceedings of the National Academy of Sciences of the United States of America; (USA) Vol. 85:7; ISSN 0027-8424; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140505* -- Solar Energy Conversion-- Photochemical
Photobiological
& Thermochemical Conversion-- (1980-)
550201 -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
BARYONS
BIOPHYSICS
CHEMICAL REACTIONS
CONFORMATIONAL CHANGES
DEUTERIUM COMPOUNDS
ELEMENTARY PARTICLES
FERMIONS
HADRONS
HYDROGEN COMPOUNDS
HYDROGEN TRANSFER
ISOMERIZATION
MEMBRANES
NUCLEONS
ORGANIC COMPOUNDS
PHOTOSYNTHETIC BACTERIA
PIGMENTS
PROTEINS
PROTONS
RAMAN SPECTRA
RHODOPSIN
SPECTRA