4LBE

Structure of KcsA with R122A mutation

4LBE の概要

• エントリーDOI: 10.2210/pdb4lbe/pdb
• 関連するPDBエントリー: 4LCU
• 分子名称: Fab light chain, Fab heavy chain, pH-gated potassium channel KcsA, ... (7 entities in total)
• 機能のキーワード: metal transport, ph-gated potassium channel, transport protein, membrane protein
• 由来する生物種: Mus musculus (mouse); 詳細
• 細胞内の位置: Cell membrane; Multi-pass membrane protein: P0A334
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 61723.94

構造登録者

Nimigean, C.M.,Posson, D.J.,McCoy, J.M. (登録日: 2013-06-20, 公開日: 2013-10-30, 最終更新日: 2024-11-06)

主引用文献

Posson, D.J.,Thompson, A.N.,McCoy, J.G.,Nimigean, C.M.
Molecular interactions involved in proton-dependent gating in KcsA potassium channels.
J.Gen.Physiol., 142:613-624, 2013

PubMed Abstract: The bacterial potassium channel KcsA is gated open by the binding of protons to amino acids on the intracellular side of the channel. We have identified, via channel mutagenesis and x-ray crystallography, two pH-sensing amino acids and a set of nearby residues involved in molecular interactions that influence gating. We found that the minimal mutation of one histidine (H25) and one glutamate (E118) near the cytoplasmic gate completely abolished pH-dependent gating. Mutation of nearby residues either alone or in pairs altered the channel's response to pH. In addition, mutations of certain pairs of residues dramatically increased the energy barriers between the closed and open states. We proposed a Monod-Wyman-Changeux model for proton binding and pH-dependent gating in KcsA, where H25 is a "strong" sensor displaying a large shift in pKa between closed and open states, and E118 is a "weak" pH sensor. Modifying model parameters that are involved in either the intrinsic gating equilibrium or the pKa values of the pH-sensing residues was sufficient to capture the effects of all mutations.

PubMed: 24218397
DOI: 10.1085/jgp.201311057

実験手法

X-RAY DIFFRACTION (2.751 Å)