A CHARACTERIZATION OF THE ACTIVATING STRUCTURAL REARRANGEMENTS IN VOLTAGE-DEPENDENT SHAKER K+ CHANNELS

被引:108
作者
MCCORMACK, K
JOINER, WJ
HEINEMANN, SH
机构
[1] YALE UNIV,SCH MED,DEPT PHYSIOL,NEW HAVEN,CT 06510
[2] MAX PLANCK INST BIOPHYS CHEM,D-37077 GOTTINGEN,GERMANY
关键词
D O I
10.1016/0896-6273(94)90273-9
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
In response to changes in membrane potential, voltage-dependent ion channel proteins undergo conformational rearrangements that lead to channel opening. These rearrangements move a net charge, measured as ''gating current,'' across the membrane. Here we characterize the effects of the pharmacological blocker 4-aminopyridine on both the K+ and gating currents of wild-type and mutant Shaker K+ channels. Our results indicate that the activation of these channels involves two distinct types of structural rearrangement. In addition to independent Hodgkin and Huxley type rearrangements for each of the four subunits, which are responsible for most of the gating charge movement, Shaker channels interconvert between two quaternary conformations during activation. The transition between the two quaternary states moves about 10% of the total gating charge, and it is selectively blocked by 4-aminopyridine.
引用
收藏
页码:301 / 315
页数:15
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