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. Author manuscript; available in PMC: 2010 May 13.
Published in final edited form as: Nat Chem Biol. 2009 Aug 9;5(9):631–639. doi: 10.1038/nchembio.195

Figure 4.

Figure 4

Point mutations within the SD mimic partial agonists. (a) The structure of the SD33 is shown highlighting the residues mutated in this study. (b) Relative affinities (Kd) of IP3 and 2 for IBC, NT, and NT with the indicated mutations (Supplementary Table 3 online); n ≥ 5. The dashed line shows KdIP3/Kd2 = 1. (c) Potency (EC50) of IP3 relative to 2 in releasing Ca2+ from permeabilized DT40 cells stably expressing mutant IP3R1 (Supplementary Table 4 online); n ≥ 5. The dashed line shows EC50IP3/EC502 = 1. (d) Typical recordings from excised nuclear patches of DT40-IP3R1V33K cells with 10μM IP3 or 2 in the patch pipette. The holding potential was +40mV. C denotes the closed state. (e) Summary data showing Po and γK for IP3R1 and IP3R1V33K stimulated with 10μM IP3 or 2; n ≥ 3. Results (b,c,e) are means ± SEM.