Skip to main content
NCBI home page
Biophysical Journal logoLink to Biophysical Journal
. 1996 Sep;71(3):1545–1553. doi: 10.1016/S0006-3495(96)79357-8

Catalysis of the retinal subpicosecond photoisomerization process in acid purple bacteriorhodopsin and some bacteriorhodopsin mutants by chloride ions.

S L Logunov 1, M A el-Sayed 1, J K Lanyi 1
PMCID: PMC1233621  PMID: 8874028

Abstract

The dynamics and the spectra of the excited state of the retinal in bacteriorhodopsin (bR) and its K-intermediate at pH 0 was compared with that of bR and halorhodopsin at pH 6.5. The quantum yield of photoisomerization in acid purple bR was estimated to be at least 0.5. The change of pH from 6.5 to 2 causes a shift of the absorption maximum from 568 to 600 nm (acid blue bR) and decreases the rate of photoisomerization. A further decrease in pH from 2 to 0 shifts the absorption maximum back to 575 nm when HCl is used (acid purple bR). We found that the rate of photoisomerization increases when the pH decreases from 2 to 0. The effect of chloride anions on the dynamics of the retinal photoisomerization of acid bR (pH 2 and 0) and some mutants (D85N, D212N, and R82Q) was also studied. The addition of 1 M HCl (to make acid purple bR, pH 0) or 1 M NaCl to acid blue bR (pH 2) was found to catalyze the rate of the retinal photoisomerization process. Similarly, the addition of 1 M NaCl to the solution of some bR mutants that have a reduced rate of retinal photoisomerization (D85N, D212N, and R82Q) was found to catalyze the rate of their retinal photoisomerization process up to the value observed in wild-type bR. These results are explained by proposing that the bound Cl- compensates for the loss of the negative charges of the COO- groups of Asp85 and/or Asp212 either by neutralization at low pH or by residue replacement in D85N and D212N mutants.

Full text

PDF
1545

Selected References

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

  1. Albeck A., Friedman N., Sheves M., Ottolenghi M. Factors affecting the absorption maxima of acidic forms of bacteriorhodopsin. A study with artificial pigments. Biophys J. 1989 Dec;56(6):1259–1265. doi: 10.1016/S0006-3495(89)82773-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Aton B., Doukas A. G., Callender R. H., Becher B., Ebrey T. G. Resonance Raman studies of the purple membrane. Biochemistry. 1977 Jun 28;16(13):2995–2999. doi: 10.1021/bi00632a029. [DOI] [PubMed] [Google Scholar]
  3. Bagley K., Dollinger G., Eisenstein L., Singh A. K., Zimányi L. Fourier transform infrared difference spectroscopy of bacteriorhodopsin and its photoproducts. Proc Natl Acad Sci U S A. 1982 Aug;79(16):4972–4976. doi: 10.1073/pnas.79.16.4972. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Brown L. S., Bonet L., Needleman R., Lanyi J. K. Estimated acid dissociation constants of the Schiff base, Asp-85, and Arg-82 during the bacteriorhodopsin photocycle. Biophys J. 1993 Jul;65(1):124–130. doi: 10.1016/S0006-3495(93)81064-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Brown L. S., Sasaki J., Kandori H., Maeda A., Needleman R., Lanyi J. K. Glutamic acid 204 is the terminal proton release group at the extracellular surface of bacteriorhodopsin. J Biol Chem. 1995 Nov 10;270(45):27122–27126. doi: 10.1074/jbc.270.45.27122. [DOI] [PubMed] [Google Scholar]
  6. Dér A., Száraz S., Tóth-Boconádi R., Tokaji Z., Keszthelyi L., Stoeckenius W. Alternative translocation of protons and halide ions by bacteriorhodopsin. Proc Natl Acad Sci U S A. 1991 Jun 1;88(11):4751–4755. doi: 10.1073/pnas.88.11.4751. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Fahmy K., Weidlich O., Engelhard M., Sigrist H., Siebert F. Aspartic acid-212 of bacteriorhodopsin is ionized in the M and N photocycle intermediates: an FTIR study on specifically 13C-labeled reconstituted purple membranes. Biochemistry. 1993 Jun 8;32(22):5862–5869. doi: 10.1021/bi00073a020. [DOI] [PubMed] [Google Scholar]
  8. Fischer U., Oesterhelt D. Chromophore equilibria in bacteriorhodopsin. Biophys J. 1979 Nov;28(2):211–230. doi: 10.1016/S0006-3495(79)85172-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Harbison G. S., Herzfeld J., Griffin R. G. Solid-state nitrogen-15 nuclear magnetic resonance study of the Schiff base in bacteriorhodopsin. Biochemistry. 1983 Jan 4;22(1):1–4. doi: 10.1021/bi00270a600. [DOI] [PubMed] [Google Scholar]
  10. Henderson R., Baldwin J. M., Ceska T. A., Zemlin F., Beckmann E., Downing K. H. Model for the structure of bacteriorhodopsin based on high-resolution electron cryo-microscopy. J Mol Biol. 1990 Jun 20;213(4):899–929. doi: 10.1016/S0022-2836(05)80271-2. [DOI] [PubMed] [Google Scholar]
  11. Honig B., Greenberg A. D., Dinur U., Ebrey T. G. Visual-pigment spectra: implications of the protonation of the retinal Schiff base. Biochemistry. 1976 Oct 19;15(21):4593–4599. doi: 10.1021/bi00666a008. [DOI] [PubMed] [Google Scholar]
  12. Kouyama T., Kinosita K., Jr, Ikegami A. Excited-state dynamics of bacteriorhodopsin. Biophys J. 1985 Jan;47(1):43–54. doi: 10.1016/S0006-3495(85)83875-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Koyama Y., Kubo K., Komori M., Yasuda H., Mukai Y. Effect of protonation on the isomerization properties of n-butylamine Schiff base of isomeric retinal as revealed by direct HPLC analyses: selection of isomerization pathways by retinal proteins. Photochem Photobiol. 1991 Sep;54(3):433–443. doi: 10.1111/j.1751-1097.1991.tb02038.x. [DOI] [PubMed] [Google Scholar]
  14. Lanyi J. K. Proton translocation mechanism and energetics in the light-driven pump bacteriorhodopsin. Biochim Biophys Acta. 1993 Dec 7;1183(2):241–261. doi: 10.1016/0005-2728(93)90226-6. [DOI] [PubMed] [Google Scholar]
  15. Lozier R. H., Bogomolni R. A., Stoeckenius W. Bacteriorhodopsin: a light-driven proton pump in Halobacterium Halobium. Biophys J. 1975 Sep;15(9):955–962. doi: 10.1016/S0006-3495(75)85875-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Marti T., Otto H., Rösselet S. J., Heyn M. P., Khorana H. G. Anion binding to the Schiff base of the bacteriorhodopsin mutants Asp-85----Asn/Asp-212----Asn and Arg-82----Gln/Asp-85----Asn/Asp-212----Asn. J Biol Chem. 1992 Aug 25;267(24):16922–16927. [PubMed] [Google Scholar]
  17. Marti T., Rösselet S. J., Otto H., Heyn M. P., Khorana H. G. The retinylidene Schiff base counterion in bacteriorhodopsin. J Biol Chem. 1991 Oct 5;266(28):18674–18683. [PubMed] [Google Scholar]
  18. Mathies R. A., Brito Cruz C. H., Pollard W. T., Shank C. V. Direct observation of the femtosecond excited-state cis-trans isomerization in bacteriorhodopsin. Science. 1988 May 6;240(4853):777–779. doi: 10.1126/science.3363359. [DOI] [PubMed] [Google Scholar]
  19. Metz G., Siebert F., Engelhard M. Asp85 is the only internal aspartic acid that gets protonated in the M intermediate and the purple-to-blue transition of bacteriorhodopsin. A solid-state 13C CP-MAS NMR investigation. FEBS Lett. 1992 Jun 1;303(2-3):237–241. doi: 10.1016/0014-5793(92)80528-o. [DOI] [PubMed] [Google Scholar]
  20. Mowery P. C., Lozier R. H., Chae Q., Tseng Y. W., Taylor M., Stoeckenius W. Effect of acid pH on the absorption spectra and photoreactions of bacteriorhodopsin. Biochemistry. 1979 Sep 18;18(19):4100–4107. doi: 10.1021/bi00586a007. [DOI] [PubMed] [Google Scholar]
  21. Needleman R., Chang M., Ni B., Váró G., Fornés J., White S. H., Lanyi J. K. Properties of Asp212----Asn bacteriorhodopsin suggest that Asp212 and Asp85 both participate in a counterion and proton acceptor complex near the Schiff base. J Biol Chem. 1991 Jun 25;266(18):11478–11484. [PubMed] [Google Scholar]
  22. 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]
  23. Polland H. J., Franz M. A., Zinth W., Kaiser W., Kölling E., Oesterhelt D. Early picosecond events in the photocycle of bacteriorhodopsin. Biophys J. 1986 Mar;49(3):651–662. doi: 10.1016/S0006-3495(86)83692-X. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Popp A., Wolperdinger M., Hampp N., Brüchle C., Oesterhelt D. Photochemical conversion of the O-intermediate to 9-cis-retinal-containing products in bacteriorhodopsin films. Biophys J. 1993 Oct;65(4):1449–1459. doi: 10.1016/S0006-3495(93)81214-1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Sasaki J., Brown L. S., Chon Y. S., Kandori H., Maeda A., Needleman R., Lanyi J. K. Conversion of bacteriorhodopsin into a chloride ion pump. Science. 1995 Jul 7;269(5220):73–75. doi: 10.1126/science.7604281. [DOI] [PubMed] [Google Scholar]
  26. Schulenberg P. J., Rohr M., Gärtner W., Braslavsky S. E. Photoinduced volume changes associated with the early transformations of bacteriorhodopsin: a laser-induced optoacoustic spectroscopy study. Biophys J. 1994 Mar;66(3 Pt 1):838–843. doi: 10.1016/s0006-3495(94)80860-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Song L., El-Sayed M. A., Lanyi J. K. Protein catalysis of the retinal subpicosecond photoisomerization in the primary process of bacteriorhodopsin photosynthesis. Science. 1993 Aug 13;261(5123):891–894. doi: 10.1126/science.261.5123.891. [DOI] [PubMed] [Google Scholar]
  28. Tittor J., Oesterhelt D., Maurer R., Desel H., Uhl R. The photochemical cycle of halorhodopsin: absolute spectra of intermediates obtained by flash photolysis and fast difference spectra measurements. Biophys J. 1987 Dec;52(6):999–1006. doi: 10.1016/S0006-3495(87)83292-7. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Xu D., Martin C., Schulten K. Molecular dynamics study of early picosecond events in the bacteriorhodopsin photocycle: dielectric response, vibrational cooling and the J, K intermediates. Biophys J. 1996 Jan;70(1):453–460. doi: 10.1016/S0006-3495(96)79588-7. [DOI] [PMC free article] [PubMed] [Google Scholar]

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

RESOURCES