PMC

Amino acid sequence alignment of IKCa, rSK2, KcsA, and Shaker showing sequence similarities within the S6 transmembrane segment. The sequence alignment of the Pore + S6 region of IKCa, rSK2, KcsA, and Shaker was based on the conserved GYGD pore motif. Sequence similarities of 100% and 75% are shaded in black and gray, respectively. The S6 segment in IKCa is presented as extending from V266 to the A286.

RP-HPLC elution profiles of phenolic fractions from the cell soluble fractions of wild-type and mutant cultures at different time points of growth. “A286” in the y axis indicates the wavelength (286 nm) used for detection. (A) Wild-type culture samples on day 0 (W-0d). (B) Wild-type culture sample at day 2 (W-2d). (C) Wild-type culture sample on day 7 (W-7d). (D) Flav mutant culture sample at day 0 (M-0d). (E) Flav mutant culture sample at day 2 (M-2d). (F) Flav mutant culture sample on day 7 (M-7d).

Protection by MTSET of TEA block for the A283C and A286C mutants. (A) Inside-out current recording illustrating the blocking action of TEA (30 mM) on the wild-type IKCa channel. (B) Inside-out recording demonstrating the lack of TEA-dependent block with the A283C mutant after application of MTSET. (C) Inside-out recording illustrating the reduced effectiveness of TEA on the A286C mutant stimulated by MTSET. (D) Histogram summarizing the effects of TEA on the wild-type IKCa channel (WT), and on the A283C and A286C mutants activated by MTSET. WT channel was blocked at 79 ± 4% (n = 6), whereas the blocking effect of TEA was reduced to 6.5 ± 4.6% (n = 3) for the A283C + MTSET mutant and to 27 ± 7% (n = 3) for the A286 mutant stimulated by MTSET.

(A) Radial distribution of the α carbons for the residues V275 to N292 along the S6 transmembrane segment computed for the closed KCa3.1 structure generated using the KcsA channel as template. The Z axis refers to the pore central axis of diffusion with z = 0 centered at the level of the V275 residue. (B) Amino acid sequence alignment of the S6 transmembrane segment in KCa3.1, KcsA, and Shaker channels. The alignment was based on the highly conserved glycine hinge at position 274 in KCa3.1. Conserved residues are shaded in black (100%) and gray (67%), respectively. The S6 segment in KCa3.1 is presented as extending from V266 to A286.