+データを開く
-基本情報
登録情報 | データベース: PDB / ID: 8fz7 | ||||||
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タイトル | TpeA bound closed MthK-A88F mutant in nanodisc | ||||||
要素 | Calcium-gated potassium channel MthK | ||||||
キーワード | MEMBRANE PROTEIN / MTHK / TRANSPORT PROTEIN / ION CHANNEL / Blocker TpeA | ||||||
機能・相同性 | 機能・相同性情報 monoatomic cation transmembrane transporter activity / potassium ion transport / identical protein binding / metal ion binding / plasma membrane 類似検索 - 分子機能 | ||||||
生物種 | Methanothermobacter thermautotrophicus (古細菌) | ||||||
手法 | 電子顕微鏡法 / 単粒子再構成法 / クライオ電子顕微鏡法 / 解像度: 2.88 Å | ||||||
データ登録者 | Agarwal, S. / Nimigean, C.M. | ||||||
資金援助 | 米国, 1件
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引用 | ジャーナル: Nat Chem Biol / 年: 2024 タイトル: Calcium-gated potassium channel blockade via membrane-facing fenestrations. 著者: Chen Fan / Emelie Flood / Nattakan Sukomon / Shubhangi Agarwal / Toby W Allen / Crina M Nimigean / 要旨: Quaternary ammonium blockers were previously shown to bind in the pore to block both open and closed conformations of large-conductance calcium-activated potassium (BK and MthK) channels. Because ...Quaternary ammonium blockers were previously shown to bind in the pore to block both open and closed conformations of large-conductance calcium-activated potassium (BK and MthK) channels. Because blocker entry was assumed through the intracellular entryway (bundle crossing), closed-pore access suggested that the gate was not at the bundle crossing. Structures of closed MthK, a Methanobacterium thermoautotrophicum homolog of BK channels, revealed a tightly constricted intracellular gate, leading us to investigate the membrane-facing fenestrations as alternative pathways for blocker access directly from the membrane. Atomistic free energy simulations showed that intracellular blockers indeed access the pore through the fenestrations, and a mutant channel with narrower fenestrations displayed no closed-state TPeA block at concentrations that blocked the wild-type channel. Apo BK channels display similar fenestrations, suggesting that blockers may use them as access paths into closed channels. Thus, membrane fenestrations represent a non-canonical pathway for selective targeting of specific channel conformations, opening novel ways to selectively drug BK channels. #1: ジャーナル: Nature / 年: 2020 タイトル: Ball-and-chain inactivation in a calcium-gated potassium channel. 著者: Chen Fan / Nattakan Sukomon / Emelie Flood / Jan Rheinberger / Toby W Allen / Crina M Nimigean / 要旨: Inactivation is the process by which ion channels terminate ion flux through their pores while the opening stimulus is still present. In neurons, inactivation of both sodium and potassium channels is ...Inactivation is the process by which ion channels terminate ion flux through their pores while the opening stimulus is still present. In neurons, inactivation of both sodium and potassium channels is crucial for the generation of action potentials and regulation of firing frequency. A cytoplasmic domain of either the channel or an accessory subunit is thought to plug the open pore to inactivate the channel via a 'ball-and-chain' mechanism. Here we use cryo-electron microscopy to identify the molecular gating mechanism in calcium-activated potassium channels by obtaining structures of the MthK channel from Methanobacterium thermoautotrophicum-a purely calcium-gated and inactivating channel-in a lipid environment. In the absence of Ca, we obtained a single structure in a closed state, which was shown by atomistic simulations to be highly flexible in lipid bilayers at ambient temperature, with large rocking motions of the gating ring and bending of pore-lining helices. In Ca-bound conditions, we obtained several structures, including multiple open-inactivated conformations, further indication of a highly dynamic protein. These different channel conformations are distinguished by rocking of the gating rings with respect to the transmembrane region, indicating symmetry breakage across the channel. Furthermore, in all conformations displaying open channel pores, the N terminus of one subunit of the channel tetramer sticks into the pore and plugs it, with free energy simulations showing that this is a strong interaction. Deletion of this N terminus leads to functionally non-inactivating channels and structures of open states without a pore plug, indicating that this previously unresolved N-terminal peptide is responsible for a ball-and-chain inactivation mechanism. | ||||||
履歴 |
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-構造の表示
構造ビューア | 分子: MolmilJmol/JSmol |
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-ダウンロードとリンク
-ダウンロード
PDBx/mmCIF形式 | 8fz7.cif.gz | 374.4 KB | 表示 | PDBx/mmCIF形式 |
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PDB形式 | pdb8fz7.ent.gz | 308 KB | 表示 | PDB形式 |
PDBx/mmJSON形式 | 8fz7.json.gz | ツリー表示 | PDBx/mmJSON形式 | |
その他 | その他のダウンロード |
-検証レポート
文書・要旨 | 8fz7_validation.pdf.gz | 1.3 MB | 表示 | wwPDB検証レポート |
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文書・詳細版 | 8fz7_full_validation.pdf.gz | 1.3 MB | 表示 | |
XML形式データ | 8fz7_validation.xml.gz | 68 KB | 表示 | |
CIF形式データ | 8fz7_validation.cif.gz | 94.2 KB | 表示 | |
アーカイブディレクトリ | https://data.pdbj.org/pub/pdb/validation_reports/fz/8fz7 ftp://data.pdbj.org/pub/pdb/validation_reports/fz/8fz7 | HTTPS FTP |
-関連構造データ
関連構造データ | 29605MC 9405C 9406C 9407C 5bkiC 5bkjC 5bkkC 8djbC C: 同じ文献を引用 (文献) M: このデータのモデリングに利用したマップデータ |
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類似構造データ | 類似検索 - 機能・相同性F&H 検索 |
-リンク
-集合体
登録構造単位 |
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-要素
#1: タンパク質 | 分子量: 37432.258 Da / 分子数: 8 / 由来タイプ: 組換発現 由来: (組換発現) Methanothermobacter thermautotrophicus (古細菌) 遺伝子: mthK, MTH_1520 / 発現宿主: Escherichia coli (大腸菌) / 参照: UniProt: O27564 #2: 化合物 | ChemComp-PGW / ( #3: 化合物 | ChemComp-YQ1 / | #4: 化合物 | 研究の焦点であるリガンドがあるか | Y | |
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-実験情報
-実験
実験 | 手法: 電子顕微鏡法 |
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EM実験 | 試料の集合状態: PARTICLE / 3次元再構成法: 単粒子再構成法 |
-試料調製
構成要素 | 名称: TpeA bound MthK A88F mutant in 0 Ca2+ / タイプ: COMPLEX / Entity ID: #1 / 由来: RECOMBINANT |
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分子量 | 値: 0.22 MDa / 実験値: YES |
由来(天然) | 生物種: Methanothermobacter thermautotrophicus (古細菌) |
由来(組換発現) | 生物種: Escherichia coli (大腸菌) |
緩衝液 | pH: 8.5 |
試料 | 濃度: 7 mg/ml / 包埋: NO / シャドウイング: NO / 染色: NO / 凍結: YES |
試料支持 | グリッドの材料: GOLD / グリッドのサイズ: 300 divisions/in. / グリッドのタイプ: UltrAuFoil R1.2/1.3 |
急速凍結 | 装置: FEI VITROBOT MARK IV / 凍結剤: ETHANE / 湿度: 100 % / 詳細: BLOTTING FOR 2 S (BLOT FORCE 0) |
-電子顕微鏡撮影
実験機器 | モデル: Titan Krios / 画像提供: FEI Company |
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顕微鏡 | モデル: FEI TITAN KRIOS |
電子銃 | 電子線源: FIELD EMISSION GUN / 加速電圧: 300 kV / 照射モード: FLOOD BEAM |
電子レンズ | モード: BRIGHT FIELD / 最大 デフォーカス(公称値): 3000 nm / 最小 デフォーカス(公称値): 500 nm |
撮影 | 電子線照射量: 58.9 e/Å2 フィルム・検出器のモデル: GATAN K2 SUMMIT (4k x 4k) |
-解析
ソフトウェア | 名称: PHENIX / バージョン: 1.19.2_4158: / 分類: 精密化 | ||||||||||||||||||||||||
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EMソフトウェア |
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CTF補正 | タイプ: PHASE FLIPPING ONLY | ||||||||||||||||||||||||
3次元再構成 | 解像度: 2.88 Å / 解像度の算出法: FSC 0.143 CUT-OFF / 粒子像の数: 105404 / 対称性のタイプ: POINT | ||||||||||||||||||||||||
原子モデル構築 | プロトコル: AB INITIO MODEL / 空間: REAL | ||||||||||||||||||||||||
原子モデル構築 | PDB-ID: 6U6D Accession code: 6U6D / Source name: PDB / タイプ: experimental model | ||||||||||||||||||||||||
拘束条件 |
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