National Institutes of Health/National Institute of Neurological Disorders and Stroke (NIH/NINDS)
4R33 NS101182-03
米国
National Institutes of Health/National Institute of Neurological Disorders and Stroke (NIH/NINDS)
R15 NS130420-01A1
米国
引用
ジャーナル: Structure / 年: 2026 タイトル: Structural basis for the subtype-selective activation of K3.1 channels. 著者: Alena Ramanishka / Joshua A Nasburg / Yang Xu / Xinyi Ma / Reza Mehvar / Meng Cui / Young-Woo Nam / Heike Wulff / Miao Zhang / 要旨: The intermediate-conductance (K3.1) and the small-conductance (K2.2) Ca-activated K channels share a Ca-calmodulin dependent gating mechanism. We report cryo-electron microscopy structures of K3.1 ...The intermediate-conductance (K3.1) and the small-conductance (K2.2) Ca-activated K channels share a Ca-calmodulin dependent gating mechanism. We report cryo-electron microscopy structures of K3.1 and K2.2 in complex with two benzothiazole-type activators. While SKA-31 is only moderately selective (∼7.3-fold), its derivative SKA-111 exhibits ∼70-fold selectivity for K3.1 over K2.2. SKA-31 and SKA-111 both bind in a pocket at the interface between the SA helix and calmodulin where they allosterically modulate the inner gate of the two channels. SKA-31 binds with comparable energies in the two channels, consistent with its moderate selectivity for K3.1 over K2.2. In the K3.1 structure, the calmodulin helix IV is positioned outward, forming a pocket that more readily accommodates the bulkier SKA-111 that sits deeper inside calmodulin's N-lobe in K3.1 than in K2.2. The resulting higher binding energy explains the improved selectivity of SKA-111 for K3.1 compared to the less selective SKA-31.
全体 : Human KCa3.1_I/calmodulin channel in complex with SKA31
全体
名称: Human KCa3.1_I/calmodulin channel in complex with SKA31
要素
複合体: Human KCa3.1_I/calmodulin channel in complex with SKA31
タンパク質・ペプチド: Intermediate conductance calcium-activated potassium channel protein 4
タンパク質・ペプチド: Calmodulin-1
リガンド: naphtho[1,2-d][1,3]thiazol-2-amine
リガンド: CALCIUM ION
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超分子 #1: Human KCa3.1_I/calmodulin channel in complex with SKA31
超分子
名称: Human KCa3.1_I/calmodulin channel in complex with SKA31 タイプ: complex / ID: 1 / 親要素: 0 / 含まれる分子: #1-#2
由来(天然)
生物種: Homo sapiens (ヒト)
分子量
理論値: 231.66 KDa
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分子 #1: Intermediate conductance calcium-activated potassium channel protein 4
分子
名称: Intermediate conductance calcium-activated potassium channel protein 4 タイプ: protein_or_peptide / ID: 1 詳細: Residues 124-141 and 229-259 were not modeled due to lack of interpretable cryo-EM density and conformational flexibility. コピー数: 4 / 光学異性体: LEVO