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Pore accessibility during C‐type inactivation in Shaker K + channels
Author(s) -
Basso Claudia,
Labarca Pedro,
Stefani Enrico,
Alvarez Osvaldo,
Latorre Ramon
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)00635-8
Subject(s) - shaker , biophysics , chemistry , extracellular , intracellular , type (biology) , channel (broadcasting) , biochemistry , biology , physics , ecology , quantum mechanics , vibration , electrical engineering , engineering
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 Ba 2+ as a probe. We determined that external Ba 2+ binds to C‐type inactivated channels forming an extremely stable complex; i.e. there is Ba 2+ trapping by C‐type inactivated channels. The structural changes Shaker channels undergo during C‐type inactivation create high energy barriers that hinder Ba 2+ exit to either the extracellular solution or to the intracellular solution.