Between the ground‐ and M‐state of bacteriorhodopsin the retinal transition dipole moment tilts out of the plane of the membrane by only 3°

FEBS Letters

Heyn, Maarten P.¹  Otto, Harald¹ 

[1] Biophysics Group, Department of Physics, Freie Universität Berlin, Arnimallee 14, D-1000 Berlin 33, Germany

关键词: Bacteriorhodopsin;    Flash spectroscopy;    Linear dichroism;    Isomerization: Retinal;   

DOI  :  10.1016/0014-5793(91)81163-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The orientation of the transition dipole moments in the ground state and the M-intermediate of bacteriorhodopsin were determined by time-resolved and steady-state polarized absorption spectroscopy on samples of oriented immobilized purple membranes. The angle between the transition dipole moment and the membrane normal decreases from 66.8±0.5° in the all-trans ground state to 64.1±0.8° in the 13-cis M-state. The light-induced isomerization of the chromophore is thus accompanied by an orientational change of only about 3° out of the plane of the membrane. The absorption anisotropy at 410 nm remains constant over more than 4 decades of time covering both the rise and decay of M. Conformational changes accompanying a sequential M₁→M₂ transition thus do not affect the chromophore orientation.

【 授权许可】

Unknown