3HPL

KcsA E71H-F103A mutant in the closed state

Summary for 3HPL

• Entry DOI: 10.2210/pdb3hpl/pdb
• Descriptor: Antibody Fab heavy chain, Antibody fab light chain, Voltage-gated potassium channel, ... (4 entities in total)
• Functional Keywords: kcsa, e71h, f103a, closed, inactivation, cell membrane, ion transport, ionic channel, membrane, transmembrane, transport, voltage-gated channel, immune system-metal transport complex, immune system/metal transport
• Biological source: Mus musculus (mouse); More
• Cellular location: Cell membrane; Multi-pass membrane protein: P0A334
• Total number of polymer chains: 3
• Total formula weight: 60226.09

Authors

Cuello, L.G.,Jogini, V.,Cortes, D.M.,Perozo, E. (deposition date: 2009-06-04, release date: 2010-06-23, Last modification date: 2024-10-16)

Primary citation

Cuello, L.G.,Jogini, V.,Cortes, D.M.,Pan, A.C.,Gagnon, D.G.,Dalmas, O.,Cordero-Morales, J.F.,Chakrapani, S.,Roux, B.,Perozo, E.
Structural basis for the coupling between activation and inactivation gates in K(+) channels.
Nature, 466:272-275, 2010

PubMed Abstract: The coupled interplay between activation and inactivation gating is a functional hallmark of K(+) channels. This coupling has been experimentally demonstrated through ion interaction effects and cysteine accessibility, and is associated with a well defined boundary of energetically coupled residues. The structure of the K(+) channel KcsA in its fully open conformation, in addition to four other partial channel openings, richly illustrates the structural basis of activation-inactivation gating. Here, we identify the mechanistic principles by which movements on the inner bundle gate trigger conformational changes at the selectivity filter, leading to the non-conductive C-type inactivated state. Analysis of a series of KcsA open structures suggests that, as a consequence of the hinge-bending and rotation of the TM2 helix, the aromatic ring of Phe 103 tilts towards residues Thr 74 and Thr 75 in the pore-helix and towards Ile 100 in the neighbouring subunit. This allows the network of hydrogen bonds among residues Trp 67, Glu 71 and Asp 80 to destabilize the selectivity filter, allowing entry to its non-conductive conformation. Mutations at position 103 have a size-dependent effect on gating kinetics: small side-chain substitutions F103A and F103C severely impair inactivation kinetics, whereas larger side chains such as F103W have more subtle effects. This suggests that the allosteric coupling between the inner helical bundle and the selectivity filter might rely on straightforward mechanical deformation propagated through a network of steric contacts. Average interactions calculated from molecular dynamics simulations show favourable open-state interaction-energies between Phe 103 and the surrounding residues. We probed similar interactions in the Shaker K(+) channel where inactivation was impaired in the mutant I470A. We propose that side-chain rearrangements at position 103 mechanically couple activation and inactivation in KcsA and a variety of other K(+) channels.

PubMed: 20613845
DOI: 10.1038/nature09136

Experimental method

X-RAY DIFFRACTION (3.2 Å)