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Voltage-dependent gating at the KcsA selectivity filter
被引:109
作者:
Cordero-Morales, JF
Cuello, LG
Perozo, E
机构:
[1] Univ Chicago, Pritzker Sch Med, Dept Biochem & Mol Biol, Chicago, IL 60637 USA
[2] Univ Virginia, Dept Mol Physiol & Biol Phys, Charlottesville, VA 22906 USA
基金:
美国国家卫生研究院;
关键词:
D O I:
10.1038/nsmb1070
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:
The prokaryotic K+ channel KcsA, although lacking a 'standard' voltage-sensing domain, shows voltage-dependent gating that leads to an increase in steady-state open probability of almost two orders of magnitude between +150 and -150 mV. Here we show that voltage- dependent gating in KcsA is associated with the movement of similar to 0.7 equivalent electronic charges. This charge movement produces an increase in the rate of entry into a long-lived inactivated state and seems to be independent of the proton-activation mechanism. Charge neutralization at position 71 renders the channel essentially voltage- independent by preventing entry into the inactivated state. A mechanism for voltage- dependent gating at the selectivity filter is proposed that is based on the reorientation of the carboxylic moiety of Glu71 and its influence in the conformational dynamics of the selectivity filter.
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页码:319 / 322
页数:4
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