Figure 3.
![Figure 3. The Ca2+ binding affinity of mutant ΔE at −80 mV. The mean log ratio of NPopen in the presence and absence of Ca2+ determined from the data shown in Fig. 2. Log (NPopen / NPopenmin) spans the entire [Ca2+] range and is fit (solid line) by Eq. 5 yielding values of KO1 = 0.7 μM, KC1 = 3.7 μM, KO2 = 21 μM, and KC2 = 51 μM. Also shown is the fit (dashed line) assuming both types of binding sites have the same affinity for Ca2+ (KO = 1.9 μM and KC = 6.4 μM). Error bars represent SEM.](https://cdn.rupress.org/rup/content_public/journal/jgp/132/5/10.1085_jgp.200810094/7/jgp_200810094_lw_fig3.jpeg?Expires=1768813539&Signature=BB~TZrGl2UO6nRJbXYV6C8NfK6pCBA~3TKzEL6SqC-GEhdJOVGd1Rpb1tmyTS1~f7pZqCux2wT1A9UMVW0RAxr6laV~MBUarGa5oXEyWb0bZAlN2L-3HcuEZp9vKXOfaa7cwkJfAxVdc9Fmyuii3r3-O7~qQ08l0AFpNBz-ovPyU4W3sYDMxcEhesrz9-pGVOt1upHom50TsQoGULX73oCIrK44r4Tz3chMzVH93KMSRfDzE3iVmuf-AGlhdRwN~DYokrczssGSOWCU2Bwo81hMO59W69izv~ui9C9iwbVyzGxz~e3mDQnF5p3ZiZnLy43nQE0HyXTfq2XPKobUIzQ__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
The Ca2+ binding affinity of mutant ΔE at −80 mV. The mean log ratio of NPopen in the presence and absence of Ca2+ determined from the data shown in Fig. 2. Log (NPopen / NPopenmin) spans the entire [Ca2+] range and is fit (solid line) by Eq. 5 yielding values of KO1 = 0.7 μM, KC1 = 3.7 μM, KO2 = 21 μM, and KC2 = 51 μM. Also shown is the fit (dashed line) assuming both types of binding sites have the same affinity for Ca2+ (KO = 1.9 μM and KC = 6.4 μM). Error bars represent SEM.
