TY - JOUR
T1 - Following evolution of bacteriorhodopsin in its reactive excited state via stimulated emission pumping
AU - Ruhman, Sanford
AU - Hou, Bixue
AU - Friedman, Noga
AU - Ottolenghi, Michael
AU - Sheves, Mordechai
PY - 2002/7/31
Y1 - 2002/7/31
N2 - New information concerning the photochemical dynamics of bacteriorhodopsin (BR) is obtained by impulsively stimulating emission from the reactive fluorescent state. Depletion of the excited-state fluorescence leads to an equal reduction in production of later photoproducts. Accordingly, chromophores which are forced back to the ground state via emission do not continue on in the photocycle, conclusively demonstrating that the fluorescent state is a photocycle intermediate. The insensitivity of depletion dynamics to the "dump" pulse timing, throughout the fluorescent states lifetime, and the biological inactivity of the dumped population suggest that the fluorescent-state structure is constant, well-defined, and significantly different than that where crossing to the ground state takes place naturally. In conjunction with conclusions from comparing the photophysics of BR with those of synthetic analogues containing "locked" retinals, present results show that large-amplitude torsion around C13=C14 is required to go between the above structures.
AB - New information concerning the photochemical dynamics of bacteriorhodopsin (BR) is obtained by impulsively stimulating emission from the reactive fluorescent state. Depletion of the excited-state fluorescence leads to an equal reduction in production of later photoproducts. Accordingly, chromophores which are forced back to the ground state via emission do not continue on in the photocycle, conclusively demonstrating that the fluorescent state is a photocycle intermediate. The insensitivity of depletion dynamics to the "dump" pulse timing, throughout the fluorescent states lifetime, and the biological inactivity of the dumped population suggest that the fluorescent-state structure is constant, well-defined, and significantly different than that where crossing to the ground state takes place naturally. In conjunction with conclusions from comparing the photophysics of BR with those of synthetic analogues containing "locked" retinals, present results show that large-amplitude torsion around C13=C14 is required to go between the above structures.
UR - http://www.scopus.com/inward/record.url?scp=0037205880&partnerID=8YFLogxK
U2 - 10.1021/ja026426q
DO - 10.1021/ja026426q
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C2 - 12137538
AN - SCOPUS:0037205880
SN - 0002-7863
VL - 124
SP - 8854
EP - 8858
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 30
ER -