Modulation of the metarhodopsin I/metarhopdopsin II equilibrium of bovine rhodopsin by ionic strength. Evidence for a surface-charge effect
| Autor: | Willem J. DeGrip, Arthur M.A. Pistorius, Frank DeLange, Petra H. M. Bovee-Geurts, Maarten Merkx |
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| Jazyk: | angličtina |
| Rok vydání: | 1997 |
| Předmět: |
Rhodopsin
Surface Properties Analysis of the dynamics of the photoreceptormembrane by means of UV/Vis and FTIR-spectroscopy Kinetics Analytical chemistry Photochemistry Biochemistry Ion Potassium Chloride Spectrophotometry Spectroscopy Fourier Transform Infrared medicine Animals Surface charge Spectroscopy GeneralLiterature_REFERENCE(e.g. dictionaries encyclopedias glossaries) medicine.diagnostic_test biology urogenital system Chemistry Osmolar Concentration Membrane Proteins Intracellular Membranes Rod Cell Outer Segment Analyse van de dynamiek van het fotoreceptormembraan met behulp van UV/Vis- en FTIR-spectroscopie Membrane Ionic strength biology.protein Cattle Spectrophotometry Ultraviolet |
| Zdroj: | European Journal of Biochemistry, 243, 1, pp. 174-180 European Journal of Biochemistry, 243, 174-180. Springer verlag European Journal of Biochemistry, 243, 1-2, pp. 174-180 European Journal of Biochemistry, 243, 174-180 European Journal of Biochemistry, 243, pp. 174-180 |
| ISSN: | 0014-2956 |
| Popis: | The effects of ionic strength on formation and decay of metarhodopsin II (MII), the active photointermediate of bovine rhodopsin, were studied in the native membrane environment by means of ultraviolet/ visible and Fourier-transform infrared (FTIR) spectroscopy. By increasing the concentration of KCl in the range from hypotonic to 4 M, the apparent pKa of the metarhodopsin I(MI)/MII equilibrium is shifted by approximately pH three, in favor of the MII intermediate. In addition, the apparent rate of MII formation is enhanced by an increase in ionic strength (about twofold in the presence of 2 M KCl). MIII decay is independent of the salt concentration. Attenuated-total-reflectance/FTIR data show that the high-salt conditions have no effect on the rigidity of the membrane matrix and do not induce structural changes in the intermediates themselves. Different salts were tested for their ability to shift the MI/MII equilibrium; however, no clear ion dependence was observed. We interpret these results as an indication for direct involvement of the cytosolic surface charge in the regulation of the photochemical activity of bovine rhodopsin. |
| Databáze: | OpenAIRE |
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