Fig. 1.

Predicted topology of chimeric β-subunits. (A) Alignment of distinct β-subunits identified to date, highlighting the main domains of their putative structure, intracellular C and N termini, transmembrane domains (TM1 and TM2), and the extracellular loop. (B) Gating charge–voltage relationships for BK (red), BK/β1 (orange), BK/β2 (blue), and BK/β3 (green) channels, from ref. 39. (C) Topological model of chimeric β1/β3-subunit constructs, in which we exchanged the main regions of the auxiliary protein, namely the extracellular loop as well as the transmembrane domains and N and C termini. The β1-subunit is shown in orange and β3 is in green.