Skip to main content
NCBI home page
Biophysical Journal logoLink to Biophysical Journal
. 1982 Feb;37(2):405–415. doi: 10.1016/S0006-3495(82)84686-9

Photoacoustic photocalorimetry and spectroscopy of Halobacterium halobium purple membranes.

H Garty, S R Caplan, D Cahen
PMCID: PMC1328822  PMID: 7059648

Abstract

Enthalpy changes associated with intermediates of the photocycle of bacteriorhodopsin (bR) in light-adapted Halobacterium halobium purple membranes, and decay times of these intermediates, are obtained from photoacoustic measurements on purple membrane fragments. Our results, mainly derived from modulation frequency spectra, show changes in the amount of energy stored in the intermediates and in their decay times as a function of pH and/or salt concentration. Especially affected are the slowest step (endothermic) and a spectroscopically unidentified intermediate (both at pH 7). This effect is interpreted in terms of cation binding to the protein, conformational changes of which are thought to be connected with the endothermic process. Wavelength spectra are used to obtain heat dissipation spectra, which allow identification of wavelength regions with varying photoactivity, and estimation of the amounts of enthalpy stored in the photointermediates. Because of bleaching and accumulation of intermediates, however, and because of the small fraction of light energy stored during photocycle, quantitative information cannot be obtained. From photoacoustic wavelength spectra of purple membrane fragments equilibrated at 63% relative humidity, rise and decay times of the bR570 and M412 intermediates are calculated.

Full text

PDF
405

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Alfano R. R., Govindjee R., Becher B., Ebrey T. G. Picosecond kinetics of the fluorescence from the chromophore of the purple membrane protein of Halobacterium halobium. Biophys J. 1976 May;16(5):541–545. doi: 10.1016/S0006-3495(76)85709-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Becher B., Ebrey T. G. The quantum efficiency for the photochemical conversion of the purple membrane protein. Biophys J. 1977 Feb;17(2):185–191. doi: 10.1016/S0006-3495(77)85636-1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Becher B., Tokunaga F., Ebrey T. G. Ultraviolet and visible absorption spectra of the purple membrane protein and the photocycle intermediates. Biochemistry. 1978 Jun 13;17(12):2293–2300. doi: 10.1021/bi00605a006. [DOI] [PubMed] [Google Scholar]
  4. Cahen D., Garty H., Caplan S. R. Spectroscopy and energetics of the purple membrane of Halobacterium halobium: a photoacoustic study. FEBS Lett. 1978 Jul 1;91(1):131–134. doi: 10.1016/0014-5793(78)80033-7. [DOI] [PubMed] [Google Scholar]
  5. Cooper A., Converse C. A. Energetics of primary processes in visula escitation: photocalorimetry of rhodopsin in rod outer segment membranes. Biochemistry. 1976 Jul 13;15(14):2970–2978. doi: 10.1021/bi00659a006. [DOI] [PubMed] [Google Scholar]
  6. Cooper A. Energetics of rhodopsin and isorhodopsin. FEBS Lett. 1979 Apr 15;100(2):382–384. doi: 10.1016/0014-5793(79)80375-0. [DOI] [PubMed] [Google Scholar]
  7. Cooper A. Energy uptake in the first step of visual excitation. Nature. 1979 Nov 29;282(5738):531–533. doi: 10.1038/282531a0. [DOI] [PubMed] [Google Scholar]
  8. Eisenbach M., Cooper S., Garty H., Johnstone R. M., Rottenberg H., Caplan S. R. Light-driven sodium transport in sub-bacterial particles of Halobacterium halobium. Biochim Biophys Acta. 1977 Mar 17;465(3):599–613. doi: 10.1016/0005-2736(77)90276-0. [DOI] [PubMed] [Google Scholar]
  9. Eisenbach M., Garty H., Bakker E. P., Klemperer G., Rottenberg H., Caplan S. R. Kinetic analysis of light-induced pH changes in bacteriorhodopsin-containing particles from Halobacterium halobium. Biochemistry. 1978 Oct 31;17(22):4691–4698. doi: 10.1021/bi00615a016. [DOI] [PubMed] [Google Scholar]
  10. Garty H., Cahen D., Caplan S. R. Photoacoustic calorimetry of Halobacterium halobium photocycle. Biochem Biophys Res Commun. 1980 Nov 17;97(1):200–206. doi: 10.1016/s0006-291x(80)80154-9. [DOI] [PubMed] [Google Scholar]
  11. Goldschmidt C. R., Kalisky O., Rosenfeld T., Ottolenghi M. The quantum efficiency of the bacteriorhodopsin photocycle. Biophys J. 1977 Feb;17(2):179–183. doi: 10.1016/S0006-3495(77)85635-X. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Hurley J. B., Becher B., Ebrey T. G. More evidence that light isomerises the cheomophore of purple membrane protein. Nature. 1978 Mar 2;272(5648):87–88. doi: 10.1038/272087a0. [DOI] [PubMed] [Google Scholar]
  13. Korenstein R., Hess B. Hydration effects on the photocycle of bacteriorhodopsin in thin layers of purple membrane. Nature. 1977 Nov 10;270(5633):184–186. doi: 10.1038/270184a0. [DOI] [PubMed] [Google Scholar]
  14. Oesterhelt D., Stoeckenius W. Isolation of the cell membrane of Halobacterium halobium and its fractionation into red and purple membrane. Methods Enzymol. 1974;31:667–678. doi: 10.1016/0076-6879(74)31072-5. [DOI] [PubMed] [Google Scholar]
  15. Oesterhelt D., Stoeckenius W. Rhodopsin-like protein from the purple membrane of Halobacterium halobium. Nat New Biol. 1971 Sep 29;233(39):149–152. doi: 10.1038/newbio233149a0. [DOI] [PubMed] [Google Scholar]
  16. Ort D. R., Parson W. W. Enthalpy changes during the photochemical cycle of bacteriorhodopsin. Biophys J. 1979 Feb;25(2 Pt 1):355–364. doi: 10.1016/s0006-3495(79)85297-2. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Ort D. R., Parson W. W. Flash-induced volume changes of bacteriorhodopsin-containing membrane fragments and their relationship to proton movements and absorbance transients. J Biol Chem. 1978 Sep 10;253(17):6158–6164. [PubMed] [Google Scholar]
  18. Ort D. R., Parson W. W. The quantum yield of flash-induced proton release by bacteriorhodopsin-containing membrane fragments. Biophys J. 1979 Feb;25(2 Pt 1):341–353. doi: 10.1016/s0006-3495(79)85296-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Slifkin M. A., Garty H., Sherman W. V., Vincent M. F., Caplan S. R. Light-induced conductivity changes in purple membrane suspensions. Biophys Struct Mech. 1979 Aug;5(4):313–320. doi: 10.1007/BF02426665. [DOI] [PubMed] [Google Scholar]
  20. Somoano R. B. Photoacoustic spectroscopy of condensed matter. Angew Chem Int Ed Engl. 1978 Apr;17(4):238–245. doi: 10.1002/anie.197802381. [DOI] [PubMed] [Google Scholar]
  21. Sperling W., Carl P., Rafferty Ch, Dencher N. A. Photochemistry and dark equilibrium of retinal isomers and bacteriorhodopsin isomers. Biophys Struct Mech. 1977 Jun 29;3(2):79–94. doi: 10.1007/BF00535798. [DOI] [PubMed] [Google Scholar]
  22. Stoeckenius W., Lozier R. H., Bogomolni R. A. Bacteriorhodopsin and the purple membrane of halobacteria. Biochim Biophys Acta. 1979 Mar 14;505(3-4):215–278. doi: 10.1016/0304-4173(79)90006-5. [DOI] [PubMed] [Google Scholar]

Articles from Biophysical Journal are provided here courtesy of The Biophysical Society

RESOURCES