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. 1987 May;51(5):839–841. doi: 10.1016/S0006-3495(87)83411-2

Bacteriorhodopsin Is a Powerful Light-Driven Proton Pump

Tsutomu Kouyama, Akemi N- Kouyama, Akira Ikegami
PMCID: PMC1329972  PMID: 19431698

Abstract

The activity of bacteriorhodopsin was investigated with Halobacterium halobium cell envelopes, which lack cytoplasmic constituents. It was found that the physiological concentration of magnesium ion greatly enhanced the light-induced pH change; under optimal conditions, the pH change of the external medium was as large as 3.5 pH units, even though the volume fraction of the envelope vesicles was as low as 0.01. This pH change is about three times larger than the largest change reported thus far. This same effect was observed with transition metal ions, but not with other alkaline divalent cations. That is, divalent cations that formed hydroxides below pH 10 were effective in enhancing the light-induced pH change. This result suggests that some divalent cations acted as buffers against a large increase in the internal pH, and that the internal pH was an important factor in determining the activity of bacteriorhodopsin. It was also shown that a high level of the proton-pump activity was maintained in a wide range of external pHs, at least between 4.5 and 9.4.

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Selected References

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

  1. Blaurock A. E., Stoeckenius W., Oesterhelt D., Scherfhof G. L. Structure of the cell envelope of Halobacterium halobium. J Cell Biol. 1976 Oct;71(1):1–22. doi: 10.1083/jcb.71.1.1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. 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]
  3. Govindjee R., Ebrey T. G., Crofts A. R. The quantum efficiency of proton pumping by the purple membrane of Halobacterium halobium. Biophys J. 1980 May;30(2):231–242. doi: 10.1016/S0006-3495(80)85091-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Helgerson S. L., Mathew M. K., Bivin D. B., Wolber P. K., Heinz E., Stoeckenius W. Coupling between the bacteriorhodopsin photocycle and the protonmotive force in Halobacterium halobium cell envelope vesicles. III. Time-resolved increase in the transmembrane electric potential and modeling of the associated ion fluxes. Biophys J. 1985 Nov;48(5):709–719. doi: 10.1016/S0006-3495(85)83829-7. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Hwang S. B., Stoeckenius W. Purple membrane vesicles: morphology and proton translocation. J Membr Biol. 1977 May 12;33(3-4):325–350. doi: 10.1007/BF01869523. [DOI] [PubMed] [Google Scholar]
  6. Kanner B. I., Racker E. Light-dependent proton and rubidium translocation in membrane vesicles from Halobacterium halobium. Biochem Biophys Res Commun. 1975 Jan 2;64(3):1054–1061. doi: 10.1016/0006-291x(75)90154-0. [DOI] [PubMed] [Google Scholar]
  7. Kayushin L. P., Skulachev V. P. Bacteriorhodopsin as an electrogenic proton pump: reconstitution of bacteriorhodopsin proteoliposomes generating delta psi and delta pH. FEBS Lett. 1974 Feb 1;39(1):39–42. doi: 10.1016/0014-5793(74)80011-6. [DOI] [PubMed] [Google Scholar]
  8. Lind C., Höjeberg B., Khorana H. G. Reconstitution of delipidated bacteriorhodopsin with endogenous polar lipids. J Biol Chem. 1981 Aug 25;256(16):8298–8305. [PubMed] [Google Scholar]
  9. Lozier R. H., Niederberger W., Bogomolni R. A., Hwang S., Stoeckenius W. Kinetics and stoichiometry of light-induced proton release and uptake from purple membrane fragments, Halobacterium halobium cell envelopes, and phospholipid vesicles containing oriented purple membrane. Biochim Biophys Acta. 1976 Sep 13;440(3):545–556. doi: 10.1016/0005-2728(76)90041-4. [DOI] [PubMed] [Google Scholar]
  10. MacDonald R. E., Lanyi L. K. Light-induced leucine transport in Halobacterium halobium envelope vesicles: a chemiosmotic system. Biochemistry. 1975 Jul;14(13):2882–2889. doi: 10.1021/bi00684a014. [DOI] [PubMed] [Google Scholar]
  11. Renthal R., Lanyi J. K. Light-induced membrane potential and pH gradient in Halobacterium halobium envelope vesicles. Biochemistry. 1976 May 18;15(10):2136–2143. doi: 10.1021/bi00655a017. [DOI] [PubMed] [Google Scholar]
  12. 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]
  13. Yoshida M., Sone N., Hirata H., Kagawa Y. ATP synthesis catalyzed by purified DCCD-sensitive ATPase incorporated into reconstituted purple membrane vesicles. Biochem Biophys Res Commun. 1975 Dec 15;67(4):1295–1300. doi: 10.1016/0006-291x(75)90167-9. [DOI] [PubMed] [Google Scholar]

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