Pore dimensions and the role of occupancy in unitary conductance of Shaker K channels.

ABSTRACT: K channels mediate the selective passage of K(+) across the plasma membrane by means of intimate interactions with ions at the pore selectivity filter located near the external face. Despite high conservation of the selectivity filter, the K(+) transport properties of different K channels vary widely, with the unitary conductance spanning a range of over two orders of magnitude. Mutation of Pro475, a residue located at the cytoplasmic entrance of the pore of the small-intermediate conductance K channel Shaker (Pro475Asp (P475D) or Pro475Gln (P475Q)), increases Shaker's reported ∼ 20-pS conductance by approximately six- and approximately threefold, respectively, without any detectable effect on its selectivity. These findings suggest that the structural determinants underlying the diversity

SUBMITTER: Diaz-Franulic I 

PROVIDER: S-EPMC4516780 | biostudies-literature | 2015 Aug

REPOSITORIES: biostudies-literature