FIGURE 7.

Deletion of the F-G loops of CBD1 and CBD2 does not alter exchanger properties. A, outward currents recorded from oocytes expressing NCX with residues 467–481 and 596–633 deleted. B, fractional activity values calculated from WT and Δ(467–481)-(596–633) currents recorded in the presence of 1.4 and 20 μm cytoplasmic Ca²⁺. C, peak values versus cytoplasmic Ca²⁺ for WT (■) and the deletion mutant (○). The apparent affinity values for the regulatory Ca²⁺ dependence of peak current are 0.86 μm for WT and 1.28 μm for Δ(467–481)-(596–633).