Review: Non-isomerizable artificial pigments: Implications for the primary light-induced events in bacteriorhodopsin

A. Aharoni, B. Hou, N. Friedman, M. Ottolenghi, I. Rousso, S. Ruhman, M. Sheves, T. Ye, Q. Zhong

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


The primary events in the photosynthetic retinal protein bacteriorhodopsin (bR) are reviewed in light of photophysical and photochemical experiments with artificial bR in which the native retinal polyene is replaced by a variety of chromophores. Focus is on retinals in which the 'critical' C13=C14 bond is locked with respect to isomerization by a rigid ring structure. Other systems include retinal oxime and non-isomerizable dyes noncovalently residing in the binding site. The early photophysical events are analyzed in view of recent pump-probe experiments with sub-picosecond time resolution comparing the behavior of bR pigments with those of model protonated Schiff bases in solution. Also described are EPR experiments monitoring reduction and oxidation reactions of a spin label covalently attached to various protein sites. It is concluded that proteins and other macromolecules may undergo structural changes following optical excitation of an appropriately (covalently or non-covalently) bound chromophore. Possible relations between the light-induced changes due to charge delocalization, and those associated with C13=C14 isomerization (that are at the basis of the bR photocycle), are discussed. It is suggested that the two effects may couple at a certain stage of the photocycle, and it is the combination of the two that drives the cross-membrane proton pump mechanism.

Original languageEnglish
Pages (from-to)1499-1510
Number of pages12
Issue number11
StatePublished - 1 Dec 2001
Externally publishedYes


  • Bacteriorhodopsin
  • Isomerization
  • Primary processes
  • Retinal

ASJC Scopus subject areas

  • Chemistry (all)


Dive into the research topics of 'Review: Non-isomerizable artificial pigments: Implications for the primary light-induced events in bacteriorhodopsin'. Together they form a unique fingerprint.

Cite this