Figure 2 of Tetreault, Mol Vis 2006; 12:1699-1705.


Figure 2. All-trans retinal shifts the cyclic GMP dose response relation of the mutant channel (N471S) into the normal range

The cGMP dose-response relation for the N471S channel (squares) can be shifted into the normal wild-type range (triangles) by addition of 150 nM ATR (circles). The physiological range of free cGMP is estimated to be a few micromolar in the dark and lower in the light. Normalized dose-response curves are for inside-out macropatches. All points were measured at +100 mV at the indicated cGMP concentration and normalized to the current in saturating cGMP (2 mM). Each data set is fit with the Hill equation: I/Imax=[cGMP]n/(K1/2 n+[cGMP]n), where I is the current amplitude, Imax is the maximum current elicited by saturating concentration of ligand, [cGMP] is the ligand concentration, K1/2 is the apparent ligand affinity, and n is the Hill coefficient. Fit parameters for each channel: wild-type cone (7 patches); K1/2=12.3 μM, n=1.8; N471S (6 patches), K1/2=4.1 μM, n=1.2; N471S+150 nM ATR (3 patches), K1/2=12.8 μM, n=1.5. Error bars represent standard errors of the mean.

(18 K)

Tetreault, Mol Vis 2006; 12:1699-1705 <http://www.molvis.org/molvis/v12/a194/>
©2006 Molecular Vision <http://www.molvis.org/molvis/>
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