FIGURE 2.

The C13 chimera is a strongly rectifying variant of ROMK (Kir1.1). Whole-cell current voltage relations from oocytes expressing either wild-type ROMK (solid line, filled squares) or the C13 chimera (dashed line, open squares). The C13 chimera was formed by replacing the C-terminus of ROMK with the homologous region from IRK1 (Kir2.1). Results were obtained with the two-electrode voltage clamp on oocytes bathed in 10 mM external K where internal pH was controlled with permeant acetate buffers (see Methods). Inset shows typical C13 currents generated by the voltage protocol around the resting potential of −60 mV.