The equilibrium between metarhodopsin I and metarhodopsin II in the isolated frog retina
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Temperature and pH dependence of the metarhodopsin I-metarhodopsin II equilibrium and the binding of metarhodopsin II to G protein in rod disk membranes
The equilibria between metarhodopsins I and II (MI and MII) and the binding of MII to retinal G protein (G) were investigated, using the dual wavelength absorbance response of rod disk membrane (RDM) suspensions to a series of small bleaches, together with a nonlinear least-squares fitting procedure that decouples the two reactions. This method has been subjected to a variety of theoretical and...
متن کاملModulation of the metarhodopsin I/metarhodopsin II equilibrium of bovine rhodopsin by ionic strength--evidence for a surface-charge effect.
The effects of ionic strength on formation and decay of metarhodopsin II (MII), the active photointermediate of bovine rhodopsin, were studied in the native membrane environment by means of ultraviolet/ visible and Fourier-transform infrared (FTIR) spectroscopy. By increasing the concentration of KCl in the range from hypotonic to 4 M, the apparent pKa of the metarhodopsin I(MI)/MII equilibrium...
متن کاملHydrogen bonding changes of internal water molecules in rhodopsin during metarhodopsin I and metarhodopsin II formation.
Rhodopsin is a 7-helix, integral membrane protein found in the rod outer segments, which serves as the light receptor in vision. Light absorption by the retinylidene chromophore of rhodopsin triggers an 11-cis-->all-trans isomerization, followed by a series of protein conformational changes, which culminate in the binding and activation of the G-protein transducin by the metarhodopsin II (Meta ...
متن کاملSignaling states of rhodopsin. Formation of the storage form, metarhodopsin III, from active metarhodopsin II.
Vertebrate rhodopsin consists of the apoprotein opsin and the chromophore 11-cis-retinal covalently linked via a protonated Schiff base. Upon photoisomerization of the chromophore to all-trans-retinal, the retinylidene linkage hydrolyzes, and all-trans-retinal dissociates from opsin. The pigment is eventually restored by recombining with enzymatically produced 11-cis-retinal. All-trans-retinal ...
متن کاملElectron crystallography reveals the structure of metarhodopsin I.
Rhodopsin is the prototypical G protein-coupled receptor, responsible for detection of dim light in vision. Upon absorption of a photon, rhodopsin undergoes structural changes, characterised by distinct photointermediates. Currently, only the ground-state structure has been described. We have determined a density map of a photostationary state highly enriched in metarhodopsin I, to a resolution...
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ژورنال
عنوان ژورنال: The Journal of Physiology
سال: 1978
ISSN: 0022-3751
DOI: 10.1113/jphysiol.1978.sp012331