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Accueil > Publications > Recherche par années > Années 2000 > 2002

Jiang, YX ; Lee, A ; Chen, JY ; Cadene, M ; Chait, BT ; MacKinnon, R

Crystal structure and mechanism of a calcium-gated potassium channel

Nature 417 (6888) 515-522

par Administrateur - publié le

Abstract :

Ion channels exhibit two essential biophysical properties ; that is, selective ion conduction, and the ability to gate-open in response to an appropriate stimulus. Two general categories of ion channel gating are defined by the initiating stimulus : ligand binding (neurotransmitter- or second-messenger-gated channels) or membrane voltage (voltage-gated channels). Here we present the structural basis of ligand gating in a K(+) channel that opens in response to intracellular Ca(2+). We have cloned, expressed, analysed electrical properties, and determined the crystal structure of a K(+) channel (MthK) from Methanobacterium thermoautotrophicum in the Ca(2+)-bound, opened state. Eight RCK domains (regulators of K(+) conductance) form a gating ring at the intracellular membrane surface. The gating ring uses the free energy of Ca(2+) binding in a simple manner to perform mechanical work to open the pore.