Positions of the cytoplasmic end of BK α S0 helix relative to S1–S6 and of β1 TM1 and TM2 relative to S0–S6
Rockefeller University Press -- The Journal of General Physiology
DOI 10.1085/jgp.201411337

The BK β1 subunit displaces the unique S0 transmembrane helix on the intracellular side of BK α but not on the extracellular side, thereby altering its path through the membrane.