Taylor, Tom
- Department of Molecular Biology, Swedish University of Agricultural Sciences
Abstract
X-ray and electron diffraction studies of specific reaction intermediates, or reaction intermediate analogues, have produced a consistent picture of the structural mechanism of light-driven proton pumping by bacteriorhodopsin. Of central importance within this picture is the structure of the L-intermediate, which follows the retinal all-trans to 13-cis photoisomerization step of the K-intermediate and sets the stage for the primary proton transfer event from the positively charged Schiff base to the negatively charged Asp-85. Here we report the structural changes in bacteriorhodopsin following red light illumination at 150 K. Single crystal microspectrophotometry showed that only the L-intermediate is populated in three-dimensional crystals under these conditions. The experimental difference Fourier electron density map and refined crystallographic structure were consistent with those previously presented (Royant, A., Edman, K., Ursby, T., Pebay-Peyroula, E., Landau, E. M., and Neutze, R. ( 2000) Nature 406, 645 - 648; Royant, A., Edman, K., Ursby, T., Pebay- Peyroula, E., Landau, E. M., and Neutze, R. ( 2001) Photochem. Photobiol. 74, 794 - 804). Based on the refined crystallographic structures, molecular dynamic simulations were used to examine the influence of the conformational change of the protein that is associated with the K-to-L transition on retinal dynamics. Implications regarding the structural mechanism for proton pumping by bacteriorhodopsin are discussed
Published in
Journal of Biological Chemistry
2004, volume: 279, number: 3, pages: 2147-2158
Publisher: AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
SLU Authors
UKÄ Subject classification
Food Science
Agricultural Science
Environmental Sciences and Nature Conservation
Publication identifier
- DOI: https://doi.org/10.1074/jbc.M300709200
Permanent link to this page (URI)
https://res.slu.se/id/publ/6071