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On the structural basis of modal gating behavior in K(+) channels.

ABSTRACT: Modal-gating shifts represent an effective regulatory mechanism by which ion channels control the extent and time course of ionic fluxes. Under steady-state conditions, the K(+) channel KcsA shows three distinct gating modes, high-P(o), low-P(o) and a high-frequency flicker mode, each with about an order of magnitude difference in their mean open times. Here we show that in the absence of C-type inactivation, mutations at the pore-helix position Glu71 unmask a series of kinetically distinct modes of gating in a side chain-specific way. These gating modes mirror those seen in wild-type channels and suggest that specific interactions in the side chain network surrounding the selectivity filter, in concert with ion occupancy, alter the relative stability of pre-existing conformational states of the pore. The present results highlight the key role of the selectivity filter in regulating modal gating behavior in K(+) channels.

SUBMITTER: Chakrapani S

PROVIDER: S-EPMC3059741 | biostudies-literature | 2011 Jan

REPOSITORIES: biostudies-literature

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On the structural basis of modal gating behavior in K(+) channels.

Chakrapani Sudha S Cordero-Morales Julio F JF Jogini Vishwanath V Pan Albert C AC Cortes D Marien DM Roux Benoît B Perozo Eduardo E

Nature structural & molecular biology 20101226 1

Modal-gating shifts represent an effective regulatory mechanism by which ion channels control the extent and time course of ionic fluxes. Under steady-state conditions, the K(+) channel KcsA shows three distinct gating modes, high-P(o), low-P(o) and a high-frequency flicker mode, each with about an order of magnitude difference in their mean open times. Here we show that in the absence of C-type inactivation, mutations at the pore-helix position Glu71 unmask a series of kinetically distinct mode ...[more]

PMID: 21186363

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