Role of protein dynamics in ion selectivity and allosteric coupling in the NaK channel.

ABSTRACT: Flux-dependent inactivation that arises from functional coupling between the inner gate and the selectivity filter is widespread in ion channels. The structural basis of this coupling has only been well characterized in KcsA. Here we present NMR data demonstrating structural and dynamic coupling between the selectivity filter and intracellular constriction point in the bacterial nonselective cation channel, NaK. This transmembrane allosteric communication must be structurally different from KcsA because the NaK selectivity filter does not collapse under low-cation conditions. Comparison of NMR spectra of the nonselective NaK and potassium-selective NaK2K indicates that the number of ion binding sites in the selectivity filter shifts the equilibrium distribution of structural states through

SUBMITTER: Brettmann JB 

PROVIDER: S-EPMC4687598 | biostudies-literature | 2015 Dec

REPOSITORIES: biostudies-literature