Evidence for light-induced 13-cis, 14-s-cis isomerization in bacteriorhodopsin obtained by FTIR difference spectroscopy using isotopically labelled retinals |
| |
Authors: | Gerwert K Siebert F |
| |
Affiliation: | Institut für Biophysik und Strahlenbiologie der Universität, Albertstrasse 23, D-7800 Freiburg i. Brsg., FRG |
| |
Abstract: | We have obtained by Fourier transformed infra-red (FTIR)-spectroscopy BR-K, BR-L and BR-M difference spectra of bacteriorhodopsin regenerated with isotopically labelled retinals. Thereby, we are able to assign reliably the C14–C15 and C=N stretching vibrations of the various intermediates. The lower C14–C15 stretching vibration frequency in L as compared with 13-cis protonated Schiff base model compounds indicates a 13-cis, 14-s-cis configuration of the retinal in this species. The unusually low C=N stretching vibration in K at 1615 cm−1 indicates less stabilization of the positive charge at the Schiff base by the protein environment. Based on these results, a mechanism is suggested by which the stored light energy is transformed into proton transfers. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|