Probing how initial retinal configuration controls photochemical dynamics in retinal proteins
1 Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
2 Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
3 Department of Life Science, Sogang University, Seoul 121-742, South Korea
The effects of the initial retinal configuration and the active isomerization coordinate on the photochemistry of retinal proteins (RPs) are assessed by comparing photochemical dynamics of two stable retinal ground state configurations (all-trans,15-anti vs. 13-cis,15-syn), within two RPs: Bacteriorhodopsin (BR) and Anabaena Sensory Rhodopsin (ASR). Hyperspectral pump-probe spectroscopy shows that photochemistry starting from 13-cis retinal in both proteins is 3-10 times faster than when started in the all-trans state, suggesting that the hastening is ubiquitous to microbial RPs, regardless of their different biological functions and origin. This may also relate to the known disparity of photochemical rates between microbial RPs and visual pigments. Importance and possible underlying mechanisms are discussed as well.
© Owned by the authors, published by EDP Sciences, 2013
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