Purchase this article with an account.
M. Kono; Effects of Noncovalent Binding of the Ring Portion of Retinal on Rod and Cone Opsin Activity. Invest. Ophthalmol. Vis. Sci. 2007;48(13):3247.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To determine how noncovalent binding of the ring portion of retinal affects rod and cone opsin activity.
COS cell membrane preparations from cells transiently transfected with rod and cone opsins were used to assess the opsins’ ability to activate transducin in the presence or absence of truncated retinal analogs using a radioactive filter binding assay.
Human M/LWS (red and green cone) opsins are readily inactivated by noncovalently bound beta ionone. Furthermore, even smaller molecules, cyclocitral and 1,3 dimethyl cyclohexane, behave as inverse agonists. Human SWS1 (blue cone) and bovine Rh1 (rhodopsin) opsins are activated by beta ionone but smaller molecules lose the ability to activate the opsins. Rh1 opsins do not require covalent linkage of ligand to be inactivated.
Noncovalent binding of ligand activates or deactivates opsins depending on opsin type and ligand. Thus, light-dependent activation of the holoprotein may proceed differently in the different pigments.
This PDF is available to Subscribers Only