Energy Transduction on the Nanosecond Time Scale: Early Structural Events in a Xanthopsin Photocycle
- 20 March 1998
- journal article
- other
- Published by American Association for the Advancement of Science (AAAS) in Science
- Vol. 279 (5358), 1946-1950
- https://doi.org/10.1126/science.279.5358.1946
Abstract
Photoactive yellow protein (PYP) is a member of the xanthopsin family of eubacterial blue-light photoreceptors. On absorption of light, PYP enters a photocycle that ultimately transduces the energy contained in a light signal into an altered biological response. Nanosecond time-resolved x-ray crystallography was used to determine the structure of the short-lived, red-shifted, intermediate state denoted [pR], which develops within 1 nanosecond after photoelectronic excitation of the chromophore of PYP by absorption of light. The resulting structural model demonstrates that the [pR] state possesses the cis conformation of the 4-hydroxyl cinnamic thioester chromophore, and that the process oftrans to cis isomerization is accompanied by the specific formation of new hydrogen bonds that replace those broken upon excitation of the chromophore. Regions of flexibility that compose the chromophore-binding pocket serve to lower the activation energy barrier between the dark state, denoted pG, and [pR], and help initiate entrance into the photocycle. Direct structural evidence is provided for the initial processes of transduction of light energy, which ultimately translate into a physiological signal.Keywords
This publication has 33 references indexed in Scilit:
- Structure of a Protein Photocycle Intermediate by Millisecond Time-Resolved CrystallographyScience, 1997
- Spectral Tuning, Fluorescence, and Photoactivity in Hybrids of Photoactive Yellow Protein, Reconstituted with Native or Modified ChromophoresJournal of Biological Chemistry, 1996
- Evidence for trans‐cis isomerization of the p‐coumaric acid chromophore as the photochemical basis of the photocycle of photoactive yellow proteinFEBS Letters, 1996
- Reconstitution photoactive yellow protein from apoprotein and p‐coumaric acid derivativesFEBS Letters, 1995
- Resonance Raman evidence that the thioester-linked 4-hydroxycinnamyl chromophore of photoactive yellow protein is deprotonatedBiochemistry, 1995
- Optical Studies of a Bacterial Photoreceptor Protein, Photoactive Yellow Protein, in Single CrystalsBiochemistry, 1995
- Structure and functions of arrestinsProtein Science, 1994
- Slow-cooling protocols for crystallographic refinement by simulated annealingActa Crystallographica Section A Foundations of Crystallography, 1990
- Isolation and characterization of soluble cytochromes, ferredoxins and other chromophoric proteins from the halophilic phototrophic bacterium Ectothiorhodospira halophilaBiochimica et Biophysica Acta (BBA) - Bioenergetics, 1985
- β-turns in proteinsJournal of Molecular Biology, 1977