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A comparison of the second harmonic generation from light-adapted, dark-adapted, blue, and acid purple membrane

Authors :
Mordechai Sheves
Aaron Lewis
O. Bouevitch
Zhongping Chen
Source :
Biophysical Journal. 67:1155-1160
Publication Year :
1994
Publisher :
Elsevier BV, 1994.

Abstract

The second order nonlinear polarizability and dipole moment changes upon light excitation of light-adapted bacteriorhodopsin (BR), dark-adapted BR, blue membrane, and acid purple membrane have been measured by second harmonic generation. Our results indicate that the dipole moment changes of the retinal chromophore, delta mu, are very sensitive to both the chromophore structure and protein/chromophore interactions. Delta mu of light-adapted BR is larger than that of dark-adapted BR. The acid-induced formation of the blue membrane results in an increase in the delta mu value, and formation of acid purple membrane, resulting from further reduction of pH to 0, returns the delta mu to that of light-adapted BR. The implications of these findings are discussed.

Details

ISSN :
00063495
Volume :
67
Database :
OpenAIRE
Journal :
Biophysical Journal
Accession number :
edsair.doi.dedup.....5a1b2f491db13a8422b70704318a34e0
Full Text :
https://doi.org/10.1016/s0006-3495(94)80583-1