Helix formation in arrestin accompanies recognition of photoactivated rhodopsin

Biochemistry. 2009 Nov 17;48(45):10733-42. doi: 10.1021/bi900544p.

Abstract

Binding of arrestin to photoactivated phosphorylated rhodopsin terminates the amplification of visual signals in photoreceptor cells. Currently, there is no crystal structure of a rhodopsin-arrestin complex available, although structures of unbound rhodopsin and arrestin have been determined. High-affinity receptor binding is dependent on distinct arrestin sites responsible for recognition of rhodopsin activation and phosphorylation. The loop connecting beta-strands V and VI in rod arrestin has been implicated in the recognition of active rhodopsin. We report the structure of receptor-bound arrestin peptide Arr(67-77) mimicking this loop based on solution NMR data. The peptide binds photoactivated rhodopsin in the unphosphorylated and phosphorylated form with similar affinities and stabilizes the metarhodopsin II photointermediate. A largely alpha-helical conformation of the receptor-bound peptide is observed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arrestin / chemistry*
  • Models, Molecular
  • Nuclear Magnetic Resonance, Biomolecular
  • Photochemistry
  • Protein Conformation
  • Rhodopsin / chemistry*

Substances

  • Arrestin
  • Rhodopsin