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Gating of the MlotiK1 potassium channel involves large rearrangements of the cyclic nucleotide-binding domains.

ABSTRACT: Cyclic nucleotide-regulated ion channels are present in bacteria, plants, vertebrates, and humans. In higher organisms, they are closely involved in signaling networks of vision and olfaction. Binding of cAMP or cGMP favors the activation of these ion channels. Despite a wealth of structural and studies, there is a lack of structural data describing the gating process in a full-length cyclic nucleotide-regulated channel. We used high-resolution atomic force microscopy (AFM) to directly observe the conformational change of the membrane embedded bacterial cyclic nucleotide-regulated channel MlotiK1. In the nucleotide-bound conformation, the cytoplasmic cyclic nucleotide-binding (CNB) domains of MlotiK1 are disposed in a fourfold symmetric arrangement forming a pore-like vestibule. Upon nucleotide-unbinding, the four CNB domains undergo a large rearrangement, stand up by ?1.7 nm, and adopt a structurally variable grouped conformation that closes the cytoplasmic vestibule. This fully reversible conformational change provides insight into how CNB domains rearrange when regulating the potassium channel.

SUBMITTER: Mari SA

PROVIDER: S-EPMC3251111 | biostudies-literature | 2011 Dec

REPOSITORIES: biostudies-literature

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Gating of the MlotiK1 potassium channel involves large rearrangements of the cyclic nucleotide-binding domains.

Mari Stefania A SA Pessoa João J Altieri Stephen S Hensen Ulf U Thomas Lise L Morais-Cabral João H JH Müller Daniel J DJ

Proceedings of the National Academy of Sciences of the United States of America 20111201 51

Cyclic nucleotide-regulated ion channels are present in bacteria, plants, vertebrates, and humans. In higher organisms, they are closely involved in signaling networks of vision and olfaction. Binding of cAMP or cGMP favors the activation of these ion channels. Despite a wealth of structural and studies, there is a lack of structural data describing the gating process in a full-length cyclic nucleotide-regulated channel. We used high-resolution atomic force microscopy (AFM) to directly observe t ...[more]

PMID: 22135457

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Gating of the MlotiK1 potassium channel involves large rearrangements of the cyclic nucleotide-binding domains.

Publications

Gating of the MlotiK1 potassium channel involves large rearrangements of the cyclic nucleotide-binding domains.

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