The flow of ions across biological membranes is central to physiological processes like nerve excitation, muscle cell contraction, and hormone secretion.The ability to select for specific ionic species and the rate of ion permeation are two fundamental properties of ion channels known as: selectivity and conductance.Since the discovery of selectivity of KcsA potassium channel twelve years ago, there are not much big progress on the key architecture of selective filter of potassium channels.Recently our high resolution structure of MthK pore (1.35A) broadens our understanding of the discrimination mechanism of K over Na in the selectivity filter of MthK potassium channel.Our single channel analysis further provide further insights of the traditional " anomalous mole-fraction effect".Conductance is one of fingerprints characters of ion channel species, but its underline mechanism is long mysteries for many years.Our high resolution MthK Pore structure also demonstrates detailed chemical environment within the ion conduction pathway.By combining structure-based mutagenesis with single channel electrophysiology and crystal structures, we probe that the effect of steric hindrance and electrostatics of residue among the cross binding of inner helix determined the conductance feature of MthK channel.High through-put screening method of ion channel breaks down the technique bottle-neck of electrophysiology assays, and further accelerates the duration of discoveries of new leading compounds.By combining single channel analysis with crystal structure also reveals the pharmacological binding site and anion selectivity mechanisms.