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Pressure-induced isomerization of retinal on bacteriorhodopsin as disclosed by fast magic angle spinning NMR.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Kawamura, Izuru Degawa, Yoshiaki Yamaguchi, Satoru Nishimura, Katsuyuki Tuzi, Satoru Saitǒ, Hazime Naito, Akira |
| Copyright Year | 2007 |
| Abstract | Bacteriorhodopsin (bR) is a retinal protein in purple membrane of Halobacterium salinarum, which functions as a light-driven proton pump. We have detected pressure-induced isomerization of retinal in bR by analyzing 15N cross polarization-magic angle spinning (CP-MAS) NMR spectra of [zeta-15N]Lys-labeled bR. In the 15N-NMR spectra, both all-trans and 13-cis retinal configurations have been observed in the Lys N(zeta) in protonated Schiff base 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 63 bar, the 15N-NMR signals of [zeta-15N]Lys in Schiff base of retinal were broadened. On the other hand, other [zeta-15N]Lys did not show broadening. Subsequently, the increased signal intensity of [zeta-15N]Lys in Schiff base of 13-cis retinal at 155.0 ppm was observed when the MAS frequency was decreased from 12 to 4 kHz. These results showed that the equilibrium constant of [all-trans-bR]/[13-cis-bR] in retinal decreased by the pressure of 63 bar. It was also revealed that the structural changes induced by the pressure occurred in the vicinity of retinal. 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 isomerization of retinal from all-trans to 13-cis state in the membrane protein bR. |
| File Format | PDF HTM / HTML |
| PubMed reference number | 17076543 |
| Journal | Medline |
| Volume Number | 83 |
| Issue Number | 2 |
| Alternate Webpage(s) | http://ir.lib.hiroshima-u.ac.jp/files/public/2/20663/20141016135419401671/PhotochemPhotobiol_83-2_346.pdf |
| Alternate Webpage(s) | https://doi.org/10.1562/2006-06-20-RC-941 |
| Journal | Photochemistry and photobiology |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
