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ID 20663
file
creator
Kawamura, Izuru
Degawa, Yoshiaki
Yamaguchi, Satoru
Nishimura, Katsuyuki
Tuzi, Satoru
Saito, Hazime
Naito, Akira
NDC
Biology
abstract
Bacteriorhodopsin (bR), a retinal protein in purple membrane of H.salinarum, shows functions as a light-driven proton pump. We have detected pressure induced isomerization of retinal in bR by 15N cross polarization-magic angle spinning (CP-MAS) NMR spectra of [ε-15N]Lys-labeled bR. In the 15N NMR spectra, both all-trans and 13-cis retinal configurations have been observed at 148.0 and 155.0 ppm, respectively, at the MAS frequency of 4 kHz in the dark. When the MAS frequency was increased up to 12 kHz corresponding to the sample pressure of 80 atm, the 15N NMR signals of Schiff Base of retinal were broadened. The signal intensity of 13-cis retinal at 155.0 ppm was increased when the MAS frequency was decreased from 12 kHz to 4 kHz. These results showed that the equilibrium constant of [13-cis –bR] /[all-trans-bR] increased by the pressure of 80 atm. It was also revealed that the changes induced by the pressure were quite local. Therefore, microscopically, hydrogen-bond network around retinal would be disrupted or distorted by a constantly applied pressure. It is, therefore, clearly demonstrated that increased pressure induced by fast MAS frequencies generated 13-cis isomerization of retinal in the membrane protein bR.
journal title
Photochemistry and Photobiology
volume
Volume 83
issue
Issue 2
start page
346
end page
350
date of issued
2007-03
publisher
American Society of Photobiology
issn
0031-8655
ncid
publisher doi
language
eng
nii type
Journal Article
HU type
Journal Articles
DCMI type
text
format
application/pdf
text version
author
rights
Author Posting. (c) The Authors (2007) This is the author's version of the work. It is posted here for personal use, not for redistribution. The definitive version was published in PHOTOCHEMISTRY AND PHOTOBIOLOGY, 83(2): 346-350. http://dx.doi.org/10.1562/2006-06-20-RC-941
relation url
department
Ohters