Figure 1.

Alignments of Amino Acids within the Pore Region of K⁺ Channels.

(A) Alignment of the pore region with parts of S5 and S6 of the voltage-dependent K⁺ channels AKT3 and KST1. Amino acids 216 to 287 of AKT3 and amino acids 217 to 289 of KST1 are shown. The identical residues in both channel proteins are highlighted by black boxes. A schematic model of the membrane topology of the chimeric channels indicates the exchanged fragment.

(B) Alignment of plant and animal K⁺ channel amino acid sequences in the pore region. Ten amino acids (c.f. sequence marked by asterisks in [A]) including the selectivity filter GYGD motif (boxed) are shown for the indicated K⁺ channels. Four amino acids upstream, the GYG sequence conserved leucine and methionine residues are marked by black boxes. The GenBank accession numbers of the aligned channels sequences are as follows: KST1, X79779; KAT1, M86990; AKT1, X62907; SKT1, X86021; ZMK1; Y07632; AKT3, U44745; ZMK2, AJ132686; KCO1, X97323; SKOR, AJ223358; Shaker, M17211; HAC1, AJ225122; SPIH1, Y16880.