Long-pore electrostatics in inward-rectifier potassium channels.

ABSTRACT: Inward-rectifier potassium (Kir) channels differ from the canonical K(+) channel structure in that they possess a long extended pore (approximately 85 A) for ion conduction that reaches deeply into the cytoplasm. This unique structural feature is presumably involved in regulating functional properties specific to Kir channels, such as conductance, rectification block, and ligand-dependent gating. To elucidate the underpinnings of these functional roles, we examine the electrostatics of an ion along this extended pore. Homology models are constructed based on the open-state model of KirBac1.1 for four mammalian Kir channels: Kir1.1/ROMK, Kir2.1/IRK, Kir3.1/GIRK, and Kir6.2/KATP. By solving the Poisson-Boltzmann equation, the electrostatic free energy of a K(+) ion is determined along each p

SUBMITTER: Robertson JL 

PROVIDER: S-EPMC2585864 | biostudies-literature | 2008 Dec

REPOSITORIES: biostudies-literature