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データを開く
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基本情報
| 登録情報 | データベース: PDB / ID: 9ots | |||||||||||||||||||||||||||
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| タイトル | Cryo-EM structure of the T9SS PORkN ring complex of P. Gingivalis | |||||||||||||||||||||||||||
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キーワード | MEMBRANE PROTEIN / T9SS / Type IX SECRETION SYSTEM / PORKN RING COMPLEX / PORPHYROMONAS GINGIVALIS / PROTEIN TRANSPORT | |||||||||||||||||||||||||||
| 機能・相同性 | 機能・相同性情報 | |||||||||||||||||||||||||||
| 生物種 | Porphyromonas gingivalis ATCC 33277 (バクテリア) | |||||||||||||||||||||||||||
| 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: 3.2 Å | |||||||||||||||||||||||||||
データ登録者 | Liu, X. / Song, L. / Zheng, L. / Hu, B. | |||||||||||||||||||||||||||
| 資金援助 | 米国, 1件
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引用 | ジャーナル: mBio / 年: 2025タイトル: Structure of the T9SS PorKN ring complex reveals conformational plasticity based on the repurposed FGE fold. 著者: Xiangan Liu / John D Perpich / Liqiang Song / Christian Cambillau / Thierry Doan / Lei Zheng / Richard J Lamont / Eric Cascales / Bo Hu / ![]() 要旨: The type IX secretion system (T9SS) is a protein secretion machinery unique to the Bacteroidetes-Chlorobi-Fibrobacteres superphylum, which plays crucial roles in bacterial pathogenesis and gliding ...The type IX secretion system (T9SS) is a protein secretion machinery unique to the Bacteroidetes-Chlorobi-Fibrobacteres superphylum, which plays crucial roles in bacterial pathogenesis and gliding motility. It is composed of >15 proteins, including the proton-motive force-dependent PorLM motor, the PorKN ring anchored to the outer membrane, and the Sov translocon. Here, we present the cryo-electron microscopy (EM) structure of the PorKN ring complex from at 3.2 Å resolution. Our structural analysis reveals that PorK contains a repurposed formylglycine-generating enzyme-like fold, which serves as a structural hub for complex assembly rather than enzymatic activity. The complex exhibits a 33-fold symmetry with PorK and PorN assembling two tightly packed and wedged subrings. The structure reveals previously uncharacterized N- and C-terminal helices in PorN that are crucial for PorK binding and complex stability. By combining our high-resolution structure with cryo-electron tomography data, we propose a mechanism whereby PorKN undergoes conformational changes during substrate transport, transitioning between 50° and 90° states relative to the membrane plane. Finally, structural predictions coupled to site-directed disulfide cross-linking identified contacts between PorM and the PorKN ring. Collectively, these findings provide crucial insights into the molecular architecture and dynamic behavior of the T9SS machinery, advancing our understanding of bacterial protein secretion mechanisms.IMPORTANCEThe bacterial type IX secretion system (T9SS) is essential for processes such as gliding motility and secretion of virulence factors. In , a major periodontal pathogen, the T9SS transports over 30 virulence-associated proteins, making it central to disease development. The T9SS core is composed of PorLM motors that are thought to energize the PorKN outer membrane-associated ring. However, the molecular architecture of the PorKN ring has remained unresolved. Here, we present its atomic-resolution cryo-EM structure, revealing a formylglycine-generating enzyme-like fold in PorK that mediates PorK-PorN interactions through specific insertion motifs. Our results show that the ring exhibits intrinsic structural plasticity, including dynamic flexibility and variable stoichiometry. AlphaFold models and disulfide cross-linking experiments further provide information on how PorLM motors are connected to the PorKN ring. These insights redefine our understanding of the T9SS mechanism of action and offer a structural framework for the development of targeted antimicrobial strategies. | |||||||||||||||||||||||||||
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構造の表示
| 構造ビューア | 分子: Molmil Jmol/JSmol |
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ダウンロードとリンク
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ダウンロード
| PDBx/mmCIF形式 | 9ots.cif.gz | 427.1 KB | 表示 | PDBx/mmCIF形式 |
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| PDB形式 | pdb9ots.ent.gz | 346.6 KB | 表示 | PDB形式 |
| PDBx/mmJSON形式 | 9ots.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
| アーカイブディレクトリ | https://data.pdbj.org/pub/pdb/validation_reports/ot/9ots ftp://data.pdbj.org/pub/pdb/validation_reports/ot/9ots | HTTPS FTP |
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-関連構造データ
| 関連構造データ | ![]() 70857MC M: このデータのモデリングに利用したマップデータ C: 同じ文献を引用 ( |
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| 類似構造データ | 類似検索 - 機能・相同性 F&H 検索 |
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リンク
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集合体
| 登録構造単位 | ![]()
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要素
| #1: タンパク質 | 分子量: 55979.594 Da / 分子数: 3 / 由来タイプ: 天然 由来: (天然) Porphyromonas gingivalis ATCC 33277 (バクテリア)株: ATCC 33277 / 参照: UniProt: B2RLF0 #2: タンパク質 | 分子量: 41519.016 Da / 分子数: 3 / 由来タイプ: 天然 由来: (天然) Porphyromonas gingivalis ATCC 33277 (バクテリア)株: ATCC 33277 / 参照: UniProt: B2RLE7 Has protein modification | N | |
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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 |
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試料調製
| 構成要素 | 名称: T9SS PorKN ring complex / タイプ: ORGANELLE OR CELLULAR COMPONENT / 由来: NATURAL |
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| 分子量 | 実験値: NO |
| 由来(天然) | 生物種: Porphyromonas gingivalis ATCC 33277 (バクテリア) |
| 緩衝液 | pH: 7.5 |
| 試料 | 包埋: NO / シャドウイング: NO / 染色: NO / 凍結: YES |
| 急速凍結 | 凍結剤: ETHANE |
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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: TFS 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): 5000 nm / 最小 デフォーカス(公称値): 1200 nm |
| 撮影 | 電子線照射量: 40 e/Å2 フィルム・検出器のモデル: GATAN K2 SUMMIT (4k x 4k) |
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解析
| EMソフトウェア |
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| CTF補正 | タイプ: PHASE FLIPPING AND AMPLITUDE CORRECTION | |||||||||||||||||||||
| 対称性 | 点対称性: C1 (非対称) | |||||||||||||||||||||
| 3次元再構成 | 解像度: 3.2 Å / 解像度の算出法: FSC 0.143 CUT-OFF / 粒子像の数: 2500000 / 対称性のタイプ: POINT | |||||||||||||||||||||
| 精密化 | 最高解像度: 3.2 Å |
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万見について




Porphyromonas gingivalis ATCC 33277 (バクテリア)
米国, 1件
引用








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FIELD EMISSION GUN