標題: Primary Conformation Change in Bacteriorhodopsin on Photoexcitation
作者: Yabushita, Atsushi
Kobayashi, Takayoshi
電子物理學系
Department of Electrophysics
公開日期: 18-二月-2009
摘要: Ultrafast dynamics of bacteriorhodopsin (bR) has been extensively studied experimentally and theoretically. However, there are several contradictory results reported, indicating that its detailed dynamics and initial process have not yet been fully clarified. In this work, changes in the amplitude and phase of molecular vibration in the isomerization process of bR were real-time probed simultaneously at 128 different wavelengths through intensity modulation of the electronic transition. Systematic information on the transient change in continuous spectrum extending from 505 nm (2.45 eV) to 675 nm (1.84 eV) showed different dynamics in each spectral region reflecting the difference in the excited states and intermediates dominating the dynamics during the photoisomerization. Careful analysis of the transient spectral changes and spectrograms calculated from the vibrational real-time traces elucidated that the primary event just after photoexcitation is the deformation of the retinal configuration, which decays within 30 fs near the C=N bond in the protonated Schiff base. The intensity of C=N stretching mode starts to decrease before the initiation of the frequency modulation of the C=C stretching mode. The C=C stretching mode frequency was modulated by a coupled torsion around the C(13)=C(14) bond, leading to the photoisomerization around the bond. This study clarified the dynamics of the C=N and C=C stretching modes working as key vibration modes in the photoisomerization of bR. Furthermore, we have elucidated the modulation and decay dynamics of the C=C stretching mode in the photoreaction starting from H (Franck-Condon excited state) followed by I (twisted excited), and J (first intermediate) states.
URI: http://dx.doi.org/10.1016/j.bpj.2008.10.050
http://hdl.handle.net/11536/7618
ISSN: 0006-3495
DOI: 10.1016/j.bpj.2008.10.050
期刊: BIOPHYSICAL JOURNAL
Volume: 96
Issue: 4
起始頁: 1447
結束頁: 1461
顯示於類別:期刊論文


文件中的檔案:

  1. 000266377800020.pdf