+データを開く
-基本情報
登録情報 | データベース: PDB / ID: 5oyb | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
タイトル | Structure of calcium-bound mTMEM16A chloride channel at 3.75 A resolution | |||||||||
要素 | Anoctamin-1 | |||||||||
キーワード | MEMBRANE PROTEIN / TMEM16 family / ion channel / cryo-EM | |||||||||
機能・相同性 | 機能・相同性情報 glial cell projection elongation / trachea development / iodide transmembrane transporter activity / iodide transport / mucus secretion / intracellularly calcium-gated chloride channel activity / cellular response to peptide / Stimuli-sensing channels / voltage-gated chloride channel activity / chloride transport ...glial cell projection elongation / trachea development / iodide transmembrane transporter activity / iodide transport / mucus secretion / intracellularly calcium-gated chloride channel activity / cellular response to peptide / Stimuli-sensing channels / voltage-gated chloride channel activity / chloride transport / chloride channel activity / positive regulation of insulin secretion involved in cellular response to glucose stimulus / detection of temperature stimulus involved in sensory perception of pain / chloride channel complex / chloride transmembrane transport / regulation of membrane potential / cell projection / establishment of localization in cell / presynaptic membrane / cellular response to heat / phospholipase C-activating G protein-coupled receptor signaling pathway / apical plasma membrane / external side of plasma membrane / signaling receptor binding / glutamatergic synapse / protein homodimerization activity / identical protein binding / metal ion binding / plasma membrane 類似検索 - 分子機能 | |||||||||
生物種 | Mus musculus (ハツカネズミ) | |||||||||
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: 3.75 Å | |||||||||
データ登録者 | Paulino, C. / Kalienkova, V. / Lam, K.M. / Neldner, Y. / Dutzler, R. | |||||||||
資金援助 | スイス, 2件
| |||||||||
引用 | ジャーナル: Nature / 年: 2017 タイトル: Activation mechanism of the calcium-activated chloride channel TMEM16A revealed by cryo-EM. 著者: Cristina Paulino / Valeria Kalienkova / Andy K M Lam / Yvonne Neldner / Raimund Dutzler / 要旨: The calcium-activated chloride channel TMEM16A is a ligand-gated anion channel that opens in response to an increase in intracellular Ca concentration. The protein is broadly expressed and ...The calcium-activated chloride channel TMEM16A is a ligand-gated anion channel that opens in response to an increase in intracellular Ca concentration. The protein is broadly expressed and contributes to diverse physiological processes, including transepithelial chloride transport and the control of electrical signalling in smooth muscles and certain neurons. As a member of the TMEM16 (or anoctamin) family of membrane proteins, TMEM16A is closely related to paralogues that function as scramblases, which facilitate the bidirectional movement of lipids across membranes. The unusual functional diversity of the TMEM16 family and the relationship between two seemingly incompatible transport mechanisms has been the focus of recent investigations. Previous breakthroughs were obtained from the X-ray structure of the lipid scramblase of the fungus Nectria haematococca (nhTMEM16), and from the cryo-electron microscopy structure of mouse TMEM16A at 6.6 Å (ref. 14). Although the latter structure disclosed the architectural differences that distinguish ion channels from lipid scramblases, its low resolution did not permit a detailed molecular description of the protein or provide any insight into its activation by Ca. Here we describe the structures of mouse TMEM16A at high resolution in the presence and absence of Ca. These structures reveal the differences between ligand-bound and ligand-free states of a calcium-activated chloride channel, and when combined with functional experiments suggest a mechanism for gating. During activation, the binding of Ca to a site located within the transmembrane domain, in the vicinity of the pore, alters the electrostatic properties of the ion conduction path and triggers a conformational rearrangement of an α-helix that comes into physical contact with the bound ligand, and thereby directly couples ligand binding and pore opening. Our study describes a process that is unique among channel proteins, but one that is presumably general for both functional branches of the TMEM16 family. | |||||||||
履歴 |
|
-構造の表示
ムービー |
ムービービューア |
---|---|
構造ビューア | 分子: MolmilJmol/JSmol |
-ダウンロードとリンク
-ダウンロード
PDBx/mmCIF形式 | 5oyb.cif.gz | 308.4 KB | 表示 | PDBx/mmCIF形式 |
---|---|---|---|---|
PDB形式 | pdb5oyb.ent.gz | 243 KB | 表示 | PDB形式 |
PDBx/mmJSON形式 | 5oyb.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 | 5oyb_validation.pdf.gz | 1.4 MB | 表示 | wwPDB検証レポート |
---|---|---|---|---|
文書・詳細版 | 5oyb_full_validation.pdf.gz | 1.4 MB | 表示 | |
XML形式データ | 5oyb_validation.xml.gz | 54.5 KB | 表示 | |
CIF形式データ | 5oyb_validation.cif.gz | 80.5 KB | 表示 | |
アーカイブディレクトリ | https://data.pdbj.org/pub/pdb/validation_reports/oy/5oyb ftp://data.pdbj.org/pub/pdb/validation_reports/oy/5oyb | HTTPS FTP |
-関連構造データ
-リンク
-集合体
登録構造単位 |
|
---|---|
1 |
|
-要素
#1: タンパク質 | 分子量: 111058.992 Da / 分子数: 2 / 由来タイプ: 組換発現 / 由来: (組換発現) Mus musculus (ハツカネズミ) / 遺伝子: Ano1, Tmem16a / 細胞株 (発現宿主): HEK293 / 発現宿主: Homo sapiens (ヒト) / 参照: UniProt: Q8BHY3 #2: 化合物 | ChemComp-CA / Has protein modification | Y | |
---|
-実験情報
-実験
実験 | 手法: 電子顕微鏡法 |
---|---|
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: mTMEM16A with calcium ions bound / タイプ: COMPLEX / 詳細: calcium-activated chloride channel / Entity ID: #1 / 由来: RECOMBINANT |
---|---|
分子量 | 値: 0.110916 MDa / 実験値: YES |
由来(天然) | 生物種: Mus musculus (ハツカネズミ) |
由来(組換発現) | 生物種: Homo sapiens (ヒト) / 株: HEK293 / 細胞: stabel mTMEM16A cell line (Flp-In System) |
緩衝液 | pH: 7.5 / 詳細: 20 mM Hepes 150 mM NaCl 0.5 mM CaCl2 <0.12% digitonin |
緩衝液成分 | 濃度: 20 mM / 名称: Hepes |
試料 | 濃度: 3.5 mg/ml / 包埋: NO / シャドウイング: NO / 染色: NO / 凍結: YES 詳細: full-length (wild-type isoform ac) deglycosylated mTMEM16A in presence of 0.5mM CaCl2 |
試料支持 | グリッドの材料: GOLD / グリッドのサイズ: 200 divisions/in. / グリッドのタイプ: Quantifoil R1.2/1.3 |
急速凍結 | 装置: FEI VITROBOT MARK IV / 凍結剤: ETHANE / 湿度: 100 % / 凍結前の試料温度: 288 K / 詳細: 2 ul sample volume 2-4 sec blotting time |
-電子顕微鏡撮影
実験機器 | モデル: Titan Krios / 画像提供: FEI Company |
---|---|
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 / 倍率(公称値): 46511 X / 倍率(補正後): 46511 X / 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 / Calibrated defocus min: 500 nm / 最大 デフォーカス(補正後): 3000 nm / Cs: 2.7 mm / C2レンズ絞り径: 100 µm / アライメント法: COMA FREE |
試料ホルダ | 凍結剤: NITROGEN 試料ホルダーモデル: FEI TITAN KRIOS AUTOGRID HOLDER 最高温度: 100 K / 最低温度: 80 K |
撮影 | 平均露光時間: 10 sec. / 電子線照射量: 80 e/Å2 / 検出モード: SUPER-RESOLUTION フィルム・検出器のモデル: GATAN K2 SUMMIT (4k x 4k) 撮影したグリッド数: 3 / 実像数: 4343 詳細: Data were collected in an automated fashion using SerialEM47 on a K2 Summit detector (Gatan). For the dataset in presence of calcium ions, cryo-EM images were collected at a pixel size of 0. ...詳細: Data were collected in an automated fashion using SerialEM47 on a K2 Summit detector (Gatan). For the dataset in presence of calcium ions, cryo-EM images were collected at a pixel size of 0.5375A in super-resolution mode, a defocus range of -0.5 to -3.0 um, an exposure time of 10 sec and a sub-frame exposure time of 125 ms (80 frames) with an approximate electron dose of 1 e-/A2/frame. An extensive effort was made for this dataset to screen different areas within the grid and only regions that provided an estimated resolution of the CTF fit of better than 4A were selected for data collection. The total accumulated dose on the specimen level was approximately 80 e-/A2. |
電子光学装置 | エネルギーフィルター名称: In-column Omega Filter エネルギーフィルター 上限: 10 eV / エネルギーフィルター 下限: -10 eV |
画像スキャン | サンプリングサイズ: 5 µm / 横: 7420 / 縦: 7676 / 動画フレーム数/画像: 80 / 利用したフレーム数/画像: 1-80 |
-解析
ソフトウェア | 名称: REFMAC / バージョン: 5.8.0158 / 分類: 精密化 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
EMソフトウェア |
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
画像処理 | 詳細: Fourier cropping (final pixel size 1.075 A), motion correction and dose-weighting of frames were performed by MotionCor2 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
CTF補正 | 詳細: The contrast transfer function (CTF) parameters were estimated on the movie frames by ctffind4.1 タイプ: PHASE FLIPPING AND AMPLITUDE CORRECTION | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
粒子像の選択 | 選択した粒子像数: 629679 詳細: For the dataset collected in presence of calcium ions a total of 4,342 dose-fractionated super-resolution images were recorded, 2 x 2 down-sampled by Fourier cropping (final pixel size 1.075A) ...詳細: For the dataset collected in presence of calcium ions a total of 4,342 dose-fractionated super-resolution images were recorded, 2 x 2 down-sampled by Fourier cropping (final pixel size 1.075A) and subjected to motion correction and dose-weighting of frames by MotionCor248. The contrast transfer function (CTF) parameters were estimated on the movie frames by ctffind4.149. Images showing a strong drift, higher defocus than -3.0 um or a bad CTF estimation were discarded, resulting in 2,997 images used for further analysis with the software package RELION2.1b150. Particles were picked automatically using 2D class averages from the previously obtained TMEM16A cryo-EM map as reference26 providing an initial set of 629,679 particles. After extraction with a box size of 300 pixels, false positives were eliminated manually or through a first round of 2D classification, resulting in 368,162 particles that were further subjected to several rounds of 2D classification to remove particles belonging to low-abundance classes. The remaining 252,577 particles were sorted during 3D Classification, a C2 symmetry was imposed and the low-resolution TMEM16A cryo-EM map (EMD-3658) was used as initial model. The best class, comprising 147,368 particles from a total of 2012 images, was subjected to auto-refinement and particle polishing in RELION, with a running average window of 5, a standard deviation of 1 pixel on translations and 200 pixels on particle distance. The final polished and auto-refined map used for model building had a resolution of 4.6A before masking and 3.75A after masking and was sharpened using an isotropic b-factor of -1063A2 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
対称性 | 点対称性: C2 (2回回転対称) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
3次元再構成 | 解像度: 3.75 Å / 解像度の算出法: FSC 0.143 CUT-OFF / 粒子像の数: 147368 / 対称性のタイプ: POINT | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
原子モデル構築 | プロトコル: RIGID BODY FIT | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
精密化 | 解像度: 3.75→129 Å / Cor.coef. Fo:Fc: 0.51 / ESU R: 5.717 立体化学のターゲット値: MAXIMUM LIKELIHOOD WITH PHASES 詳細: HYDROGENS HAVE BEEN ADDED IN THE RIDING POSITIONS
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
溶媒の処理 | イオンプローブ半径: 0.8 Å / 減衰半径: 0.8 Å / VDWプローブ半径: 1.2 Å / 溶媒モデル: MASK | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
原子変位パラメータ | Biso mean: 126.79 Å2
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
精密化ステップ | サイクル: 1 / 合計: 11770 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
拘束条件 |
|