Photocyclic behavior of rhodopsin induced by an atypical isomerization mechanism
Abstract
Vertebrate rhodopsin (Rh) has been a model system for many G protein-coupled receptors for over a decade. However, due to its thus-far limited repertoire of active ligands, its use in assisting the development of new therapeutic modalities and drugs has been limited. This study elucidates a photocyclic G protein activation by Rh bound with a six-carbon ring retinal (Rh6mr), and thus broadens the diversity of such Rh signaling modulators. Rh6mr does not release its chromophore after light activation, but instead the resulting photoproduct is thermally reisomerized back to its inactive state, abrogating the necessity for a complex retinoid cycle to renew its chromophore. This photocyclic behavior of Rh6mr opens up several avenues for using optogenetic tools based on vertebrate Rhs.
- Publication:
-
Proceedings of the National Academy of Science
- Pub Date:
- March 2017
- DOI:
- 10.1073/pnas.1617446114
- Bibcode:
- 2017PNAS..114E2608G