A methyl group at C7 of 11-cis-retinal allows chromophore formation but affects rhodopsin activation

Vision Res. 2006 Dec;46(27):4472-81. doi: 10.1016/j.visres.2006.07.031. Epub 2006 Oct 6.

Abstract

The newly synthesized 11-cis-7-methylretinal can form an artificial visual pigment with kinetic and spectroscopic properties similar to the native pigment in the dark-state. However, its photobleaching behavior is altered, showing a Meta I-like photoproduct. This behavior reflects a steric constraint imposed by the 7-methyl group that affects the conformational change in the binding pocket as a result of retinal photoisomerization. Transducin activation is reduced, when compared to the native pigment with 11-cis-retinal. Molecular dynamics simulations suggest coupling of the C7 methyl group and the beta-ionone ring with Met207 in transmembrane helix 5 in agreement with recent experimental results.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • COS Cells
  • Chlorocebus aethiops
  • Computer Simulation
  • Dark Adaptation
  • Diterpenes
  • GTP-Binding Proteins / metabolism
  • Humans
  • Models, Molecular
  • Protein Binding
  • Retinaldehyde / analogs & derivatives*
  • Retinaldehyde / chemistry
  • Retinaldehyde / metabolism
  • Rhodopsin / metabolism*
  • Rod Cell Outer Segment / metabolism*
  • Stereoisomerism
  • Structure-Activity Relationship
  • Transducin / metabolism*
  • Vision, Ocular / physiology

Substances

  • 7-methylretinal
  • 8-methylretinal
  • Diterpenes
  • Rhodopsin
  • GTP-Binding Proteins
  • Transducin
  • Retinaldehyde