title: Determinants of cation transport selectivity: Equilibrium binding and transport kinetics.
abstract: The crystal structures of channels and transporters reveal the chemical nature of ion-binding sites and, thereby, constrain mechanistic models for their transport processes. However, these structures, in and of themselves, do not reveal equilibrium selectivity or transport preferences, which can be discerned only from various functional assays. In this Review, I explore the relationship between cation transport protein structures, equilibrium binding measurements, and ion transport selectivity. The primary focus is on K(+)-selective channels and nonselective cation channels because they have been extensively studied both functionally and structurally, but the principles discussed are relevant to other transport proteins and molecules.
authors.affiliation: Department of Biology, Texas A&M University, College Station, TX 77843 lockless@bio.tamu.edu.
authors.forename: Steve W
authors.initials: SW
authors.lastname: Lockless
mesh_terms: D001665:Binding Sites / Q000502:physiology*; D002412:Cations / Q000378:metabolism*; D018360:Crystallography, X-Ray / Q000379:methods; D015640:Ion Channel Gating / Q000502:physiology*; D017136:Ion Transport / Q000502:physiology*; D007700:Kinetics; D015221:Potassium Channels / Q000378:metabolism
chemical_list: D002412:Cations; D015221:Potassium Channels