title: Pore accessibility during C-type inactivation in Shaker K+ channels.
abstract: Shaker K+ channels inactivate through two distinct molecular mechanisms: N-type, which involves the N-terminal domain and C-type that appears to involve structural modifications at the external mouth of the channel. We have tested pore accessibility of the Shaker K+ channel during C-type inactivation using Ba2+ as a probe. We determined that external Ba2+ binds to C-type inactivated channels forming an extremely stable complex; i.e. there is Ba2+ trapping by C-type inactivated channels. The structural changes Shaker channels undergo during C-type inactivation create high energy barriers that hinder Ba2+ exit to either the extracellular solution or to the intracellular solution.
authors.affiliation: Departmento of Biología, Facultad de Ciencias, Universidad de Chile, Santiago.
authors.forename: C
authors.initials: C
authors.lastname: Basso
authors.forename: P
authors.initials: P
authors.lastname: Labarca
authors.forename: E
authors.initials: E
authors.lastname: Stefani
authors.forename: O
authors.initials: O
authors.lastname: Alvarez
authors.forename: R
authors.initials: R
authors.lastname: Latorre
mesh_terms: D001464:Barium / Q000494:pharmacology*; D001692:Biological Transport; D015640:Ion Channel Gating; D008956:Models, Chemical; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism*; D011487:Protein Conformation; D051637:Shaker Superfamily of Potassium Channels
chemical_list: D015221:Potassium Channels; D051637:Shaker Superfamily of Potassium Channels; D001464:Barium