Pore accessibility during C-type inactivation in Shaker K+ channels

被引:18
作者
Basso, C
Labarca, P
Stefani, E
Alvarez, O
Latorre, R
机构
[1] Ctr Estudios Cient Santiago, Santiago 9, Chile
[2] Univ Chile, Fac Ciencias, Dept Biol, Santiago, Chile
[3] CONICET, RA-1033 Buenos Aires, DF, Argentina
[4] Univ Calif Los Angeles, Dept Anesthesiol, Los Angeles, CA 90095 USA
[5] Univ Calif Los Angeles, Dept Physiol, Los Angeles, CA 90095 USA
[6] Univ Calif Los Angeles, Brain Res Inst, Los Angeles, CA 90095 USA
关键词
Shaker K+ channel; slow inactivation; pore accessibility; Ba2+ block;
D O I
10.1016/S0014-5793(98)00635-8
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Shaker K+ channels inactivate through tno 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. (C) 1998 Federation of European Biochemical Societies.
引用
收藏
页码:375 / 380
页数:6
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