Modelling of photointermediates suggests a mechanism of the flip of the beta-ionone moiety of the retinylidene chromophore in the rhodopsin photocascade.

@article{Ishiguro2003ModellingOP,
  title={Modelling of photointermediates suggests a mechanism of the flip of the beta-ionone moiety of the retinylidene chromophore in the rhodopsin photocascade.},
  author={Masaji Ishiguro and Takahiro Hirano and Yoshiaki Oyama},
  journal={Chembiochem : a European journal of chemical biology},
  year={2003},
  volume={4 2-3},
  pages={
          228-31
        }
}