Effect of GTP on the rhodopsin-G-protein complex by transient formation of extra metarhodopsin II

Biochim Biophys Acta. 1985 Nov 27;810(2):278-81. doi: 10.1016/0005-2728(85)90143-4.

Abstract

The light-induced transient interaction between rhodopsin and G-protein in the presence of GTP has been measured by the formation of extra metarhodopsin II. Disc membranes were recombined with the hypotonic extract containing the G-protein. Without GTP, a flash induces stable rhodopsin-G-protein complexes which dissociate upon addition of GTP. In low GTP (less than 10 microM) transient rhodopsin X G-protein interaction is observed. Rhodopsin X G-protein dissociates the faster, the more GTP is present (rate of dissociation, 0.3/s at 5 microM GTP; T = 3.5 degrees C). The results corroborate that the uptake of GTP terminates the rhodopsin-G-protein complex and allow an estimation of the rhodopsin X G-protein lifetime.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cattle
  • GTP-Binding Proteins / metabolism*
  • Guanosine Triphosphate / pharmacology*
  • Kinetics
  • Light
  • Retinal Pigments / metabolism*
  • Rhodopsin / analogs & derivatives
  • Rhodopsin / metabolism*
  • Rod Cell Outer Segment / analysis

Substances

  • Retinal Pigments
  • metarhodopsins
  • Guanosine Triphosphate
  • Rhodopsin
  • GTP-Binding Proteins