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Structural changes in the photoactive site of proteorhodopsin during the primary photoreaction.

Publication ,  Journal Article
Bergo, V; Amsden, JJ; Spudich, EN; Spudich, JL; Rothschild, KJ
Published in: Biochemistry
July 2004

Proteorhodopsin (PR), found in marine gamma-proteobacteria, is a newly discovered light-driven proton pump similar to bacteriorhodopsin (BR). Because of the widespread distribution of proteobacteria in the worldwide oceanic waters, this pigment may contribute significantly to the global solar energy input in the biosphere. We examined structural changes that occur during the primary photoreaction (PR --> K) of wild-type pigment and two mutants using low-temperature FTIR difference spectroscopy. Several vibrations detected in the 3500-3700 cm(-1) region are assigned on the basis of H(2)O --> H(2)(18)O exchange to the perturbation of one or more internal water molecules. Substitution of the negatively charged Schiff base counterion, Asp97, with the neutral asparagine caused a downshift of the ethylenic (C=C) and Schiff base (C=N) stretching modes, in agreement with the 27 nm red shift of the visible lambda(max). However, this replacement did not alter the normal all-trans to 13-cis isomerization of the chromophore or the environment of the detected water molecule(s). In contrast, substitution of Asn230, which is in a position to interact with the Schiff base, with Ala induces a 5 nm red shift of the visible lambda(max) and alters the PR chromophore structure, its isomerization to K, and the environment of the detected internal water molecules. The combination of FTIR and site-directed mutagenesis establishes that both Asp97 and Asn230 are perturbed during the primary phototransition. The environment of Asn230 is further altered during the thermal decay of K. These results suggest that significant differences exist in the conformational changes which occur in the photoactive sites of proteorhodopsin and bacteriorhodopsin during the primary photoreaction.

Duke Scholars

Published In

Biochemistry

DOI

EISSN

1520-4995

ISSN

0006-2960

Publication Date

July 2004

Volume

43

Issue

28

Start / End Page

9075 / 9083

Related Subject Headings

  • Spectroscopy, Fourier Transform Infrared
  • Schiff Bases
  • Rhodopsins, Microbial
  • Rhodopsin
  • Proteobacteria
  • Mutation
  • Molecular Structure
  • Liposomes
  • Light
  • Isomerism
 

Citation

APA
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ICMJE
MLA
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Bergo, V., Amsden, J. J., Spudich, E. N., Spudich, J. L., & Rothschild, K. J. (2004). Structural changes in the photoactive site of proteorhodopsin during the primary photoreaction. Biochemistry, 43(28), 9075–9083. https://doi.org/10.1021/bi0361968
Bergo, Vladislav, Jason J. Amsden, Elena N. Spudich, John L. Spudich, and Kenneth J. Rothschild. “Structural changes in the photoactive site of proteorhodopsin during the primary photoreaction.Biochemistry 43, no. 28 (July 2004): 9075–83. https://doi.org/10.1021/bi0361968.
Bergo V, Amsden JJ, Spudich EN, Spudich JL, Rothschild KJ. Structural changes in the photoactive site of proteorhodopsin during the primary photoreaction. Biochemistry. 2004 Jul;43(28):9075–83.
Bergo, Vladislav, et al. “Structural changes in the photoactive site of proteorhodopsin during the primary photoreaction.Biochemistry, vol. 43, no. 28, July 2004, pp. 9075–83. Epmc, doi:10.1021/bi0361968.
Bergo V, Amsden JJ, Spudich EN, Spudich JL, Rothschild KJ. Structural changes in the photoactive site of proteorhodopsin during the primary photoreaction. Biochemistry. 2004 Jul;43(28):9075–9083.
Journal cover image

Published In

Biochemistry

DOI

EISSN

1520-4995

ISSN

0006-2960

Publication Date

July 2004

Volume

43

Issue

28

Start / End Page

9075 / 9083

Related Subject Headings

  • Spectroscopy, Fourier Transform Infrared
  • Schiff Bases
  • Rhodopsins, Microbial
  • Rhodopsin
  • Proteobacteria
  • Mutation
  • Molecular Structure
  • Liposomes
  • Light
  • Isomerism