Exploring the active site structure of a photoreceptor protein by Raman optical activity.
We have developed a near-infrared excited Raman optical activity (ROA) spectrometer and report the first measurement of near-infrared ROA spectra of a light-driven proton pump, bacteriorhodopsin. Our results demonstrate that a near-infrared excitation enables us to measure the ROA spectra of the chromophore within a protein environment. Furthermore, the ROA spectra of the all-trans, 15-anti and 13-cis, 15-syn isomers differ significantly, indicating a high structural sensitivity of the ROA spectra. We therefore expect that future applications of the near-infrared ROA will allow the experimental elucidation of the active site structures in other proteins as well as reaction intermediates.
Department of Chemistry and Applied Chemistry, Graduate School of Science and Engineering, Saga University, Saga 840-8502, Japan. unno@cc.saga-u.ac.jp
Masashi
M
Unno
Takashi
T
Kikukawa
Masato
M
Kumauchi
Naoki
N
Kamo
D001436:Bacteriorhodopsins / Q000737:chemistry* / Q000378:metabolism; D020134:Catalytic Domain; D019617:Halobacterium salinarum; D008958:Models, Molecular; D013059:Spectrum Analysis, Raman
D001436:Bacteriorhodopsins