I/Q versus voltage from oocytes expressing Ca1.2 E462R after the injection of purified Caβ protein at the indicated concentrations. Traces correspond to superimposed responses to three 60-ms depolarizing pulses to −30 mV, 0 mV, and +30 mV from a holding voltage of −90 mV. Calibration bars correspond to 20 ms and 200 nA. Experimental I/Q values (8) were fitted to the equation (blue line):Each member of the equation corresponds to templates in absence (−) or presence (+) of saturating concentration of Caβ protein (2.0 μM). Variables defining each template were obtained from the fit to average I/Q plot from each condition. The contribution of +β and −β templates are shown as green and red lines, respectively. (B) As A) but for Ca1.2 K465N. (C) Mean ± SE of β2a-like versus protein concentration ([Caβ]) in μM. Continuous lines show the fit to a standard Hill equation:Where is the apparent dissociation constant and is the Hill coefficient. ranged between 1.4 and 1.6, whereas for WT, E462R, and K465N was 0.20, 0.22, and 0.25 μM, respectively. The number of averaged experiments ranged from three to six for every concentration and calcium channel variant.<p><b>Copyright information:</b></p><p>Taken from "Mutations of Nonconserved Residues within the Calcium Channel α-interaction Domain Inhibit β-Subunit Potentiation"</p><p></p><p>The Journal of General Physiology 2008;132(3):383-395.</p><p>Published online Jan 2008</p><p>PMCID:PMC2518731.</p><p></p
