FIGURE 3.

Decreased BmP05 potency for SK3 channels resulting from increased content of basic residues in the BmP05 channel-binding surface. A, one or two arginine residues (shown in red) were introduced into the channel-interacting surface. B, CD spectra of recombinant BmP05, BmP05-S14R, BmP05-L15R, BmP05-N4R/S14R, and BmP05-N4R/L15R peptides. Measurements were carried out in the UV range of 250–190 nm at 25 °C in water on a Jasco-810 spectropolarimeter at a concentration of 0.2–0.4 mg/ml. C–F, representative current traces of the SK3 channel showing reduced inhibition by 100 nm BmP05 mutants. C, 20.5% block by BmP05-S14R. D, 30.5% block by BmP05-L15R. E, 8.5% block by BmP05-N4R/S14R. F, 10.7% block by BmP05-N4R/L15R.