Molecular basis for functional connectivity between the voltage sensor and the selectivity filter gate in Shaker K+ channels

• DOI: 10.7554/elife.63077
• Publication Date: 2021-02-23T13:00:39Z
• Authors: Carlos AZ Bassetto; João Luis Carvalh...; Francisco Bezanilla
• Keywords: Shaker; KcsA potassium channel

In Shaker K + channels, the S4-S5 linker couples voltage sensor (VSD) and pore domain (PD). Another coupling mechanism is revealed using two W434F-containing channels: L361R:W434F L366H:W434F. L361R:W434F, W434F affects L361R VSD seen as a shallower charge-voltage (Q-V) curve that crosses conductance-voltage (G-V) curve. L366H:W434F, L366H relieves effect converting non-conductive channel in conductive one. We report chain of residues connecting (S4) to selectivity filter (SF) PD an adjacent subunit molecular basis for gate (VS-SF) coupling. Single alanine substitutions this region (L409A, S411A, S412A, or F433A) are enough disrupt VS-SF coupling, shown by absence Q-V G-V crossing mutant lack ionic conduction L366H:W434F mutant. This residue defines new between voltage-gated channels.