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Light‐dependent trans to cis isomerization of the retinal in halorhodopsin
Author(s) -
Lanyi Janos K.
Publication year - 1984
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(84)80764-4
Subject(s) - halorhodopsin , bacteriorhodopsin , isomerization , photochemistry , deprotonation , chemistry , retinal , halobacteriaceae , flash photolysis , protonation , biophysics , kinetics , biochemistry , halobacterium salinarum , biology , physics , organic chemistry , reaction rate constant , ion , catalysis , quantum mechanics , membrane
Flash‐induced absorption changes in the near UV were determined for bacteriorhodopsin and halorhodopsin on a millisecond time scale. The difference spectrum obtained for bacteriorhodopsin was comparable to model difference spectra of tyrosine (aromatic OH deprotonated vs protonated), as found by others. The flash‐induced difference spectrum for halorhodopsin, in contrast, resembled a model spectrum opbtained for trans to 13‐ cis isomerization of retinal in bacteriorhodopsin. A model for chloride translocation by halorhodopsin is presented, in which the retinal isomerization moves positive charges, which in turn modulate the affinity of a site to chloride.