Table of Contents
Laser Chemistry
Volume 19 (1999), Issue 1-4, Pages 165-168
http://dx.doi.org/10.1155/1999/93486

Time-Resolved Ultraviolet Resonance Raman of Protein Structural Changes in The KI-Intermediate Of Bacteriorhodopsin

Department of Chemistry, University of California, Berkeley CA 94720, USA

Received 7 April 1997

Copyright © 1999 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

To obtain high quality time-resolved ultraviolet resonance Raman (UVRR) spectra of transient intermediates in the bacteriorhodopsin (BR) photocycle, we developed a new UVRR spectrometer. A home-made F=3.5 prism prefilter was used in front of a 50 cm CCD detected spectrograph to give high throughput, wide tunability, and excellent stray light rejection along with low dispersion. Using this system, we obtained 239.5 nm excited time-resolved UVRR spectra of BR which revealed small but significant features associated with the formation of the KL-intermediate at 10 ns delays. This difference spectrum exhibits intensity decreases at 1624, 1561, 1012 and 763cm-1 due to an altered environment of one or more Trp residues and a frequency shift of the Tyr ʋ8b band at 1602 cm-1. These signals show that the photoisomerization of retinal from all-trans to 13-cis induces significant changes in the structure and environment of aromatic residues that line the retinal binding pocket in only 10 ns.