Fourier transform infrared evidence for proline structural changes during the bacteriorhodopsin photocycle

Journal Article · Fri Dec 01 04:00:00 EST 1989 · Proceedings of the National Academy of Sciences of the United States of America; (USA)

DOI:https://doi.org/10.1073/pnas.86.24.9832· OSTI ID:7152020

Rothschild, K J; He, Y W; Gray, D; Roepe, P D; Pelletier, S L; Brown, R S; Herzfeld, J ^[1]

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1. Boston Univ., MA (USA)

Structural changes involving bacteriohodopsin proline residues have been investigated by Fourier transform infrared difference spectroscopy. Bacteriohodopsin (bR)-producing Halobacteria halobium were grown on a stringent medium containing either ring-perdeuterated proline or 15N-labeled proline. Comparison of the difference spectra obtained from the photoreactions of these labeled bR samples with those for unlabeled bR has led to the assignment of peaks due to proline vibrations. (proline-N15)bR exhibited a 15-cm-1 isotopic downshift of peaks in the 1420- to 1440-cm-1 region of the bR----K and bR----M difference spectra as well as a similar downshift of peaks found in the absolute absorption spectrum of bR. In contrast, (proline-D7)bR did not cause shifts in this region of the difference spectra. These results indicate that one or more prolines undergo a structural rearrangement during the bR photocycle involving the Xaa-Pro C--N peptide bond. This change may be directly coupled to the light-induced isomerization of the retinal chromophore from all-trans-retinal to 13-cis-retinal.

• OSTI ID: 7152020
• 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. 86:24; ISSN PNASA; ISSN 0027-8424
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ABSORPTION SPECTRA
AMINES
AMINO ACIDS
AZOLES
BIOCHEMICAL REACTION KINETICS
CARBOXYLIC ACID ESTERS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
DEUTERIUM
ESTERS
FOURIER TRANSFORMATION
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROGEN ISOTOPES
INFRARED SPECTRA
INTEGRAL TRANSFORMATIONS
ISOMERIZATION
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIGHT NUCLEI
MORPHOLOGICAL CHANGES
NITROGEN 15
NITROGEN ISOTOPES
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOSYNTHETIC BACTERIA
PIGMENTS
PROLINE
PROTEINS
PYRROLES
PYRROLIDINES
REACTION KINETICS
RETINOIC ACID
RHODOPSIN
SPECTRA
STABLE ISOTOPES
TRACER TECHNIQUES
TRANSFORMATIONS
ULTRASTRUCTURAL CHANGES