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基本情報
登録情報 | データベース: PDB / ID: 6ar6 | ||||||||||||
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タイトル | Clostridioides difficile toxinB with DLD-4 darpin | ||||||||||||
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![]() | TOXIN/PROTEIN BINDING / TOXIN-PROTEIN BINDING complex | ||||||||||||
機能・相同性 | ![]() glucosyltransferase activity / host cell cytosol / 転移酵素; グリコシル基を移すもの; 六炭糖残基を移すもの / cysteine-type peptidase activity / host cell endosome membrane / toxin activity / 加水分解酵素; プロテアーゼ; ペプチド結合加水分解酵素; システインプロテアーゼ / lipid binding / host cell plasma membrane / proteolysis ...glucosyltransferase activity / host cell cytosol / 転移酵素; グリコシル基を移すもの; 六炭糖残基を移すもの / cysteine-type peptidase activity / host cell endosome membrane / toxin activity / 加水分解酵素; プロテアーゼ; ペプチド結合加水分解酵素; システインプロテアーゼ / lipid binding / host cell plasma membrane / proteolysis / extracellular region / membrane / metal ion binding 類似検索 - 分子機能 | ||||||||||||
生物種 | ![]() ![]() ![]() | ||||||||||||
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: 9 Å | ||||||||||||
![]() | Zhang, J. / Jiang, M. | ||||||||||||
資金援助 | ![]()
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![]() | ![]() タイトル: Selection and characterization of ultrahigh potency designed ankyrin repeat protein inhibitors of C. difficile toxin B. 著者: Rudo Simeon / Mengqiu Jiang / Ana M Chamoun-Emanuelli / Hua Yu / Yongrong Zhang / Ran Meng / Zeyu Peng / Joanita Jakana / Junjie Zhang / Hanping Feng / Zhilei Chen / ![]() 要旨: Clostridium difficile infection (CDI) is a major nosocomial disease associated with significant morbidity and mortality. The pathology of CDI stems primarily from the 2 C. difficile-secreted ...Clostridium difficile infection (CDI) is a major nosocomial disease associated with significant morbidity and mortality. The pathology of CDI stems primarily from the 2 C. difficile-secreted exotoxins-toxin A (TcdA) and toxin B (TcdB)-that disrupt the tight junctions between epithelial cells leading to the loss of colonic epithelial barrier function. Here, we report the engineering of a series of monomeric and dimeric designed ankyrin repeat proteins (DARPins) for the neutralization of TcdB. The best dimeric DARPin, DLD-4, inhibited TcdB with a half maximal effective concentration (EC50) of 4 pM in vitro, representing an approximately 330-fold higher potency than the Food and Drug Administration (FDA)-approved anti-TcdB monoclonal antibody bezlotoxumab in the same assay. DLD-4 also protected mice from a toxin challenge in vivo. Cryo-electron microscopy (cryo-EM) studies revealed that the 2 constituent DARPins of DLD-4-1.4E and U3-bind the central and C-terminal regions of the delivery domain of TcdB. Competitive enzyme-linked immunosorbent assay (ELISA) studies showed that the DARPins 1.4E and U3 interfere with the interaction between TcdB and its receptors chondroitin sulfate proteoglycan 4 (CSPG4) and frizzled class receptor 2 (FZD2), respectively. Our cryo-EM studies revealed a new conformation of TcdB (both apo- and DARPin-bound at pH 7.4) in which the combined repetitive oligopeptides (CROPS) domain points away from the delivery domain. This conformation of the CROPS domain is in stark contrast to that seen in the negative-stain electron microscopy (EM) structure of TcdA and TcdB at the same pH, in which the CROPS domain bends toward and "kisses" the delivery domain. The ultrapotent anti-TcdB molecules from this study serve as candidate starting points for CDI drug development and provide new biological tools for studying the pathogenicity of C. difficile. The structural insights regarding both the "native" conformation of TcdB and the putative sites of TcdB interaction with the FZD2 receptor, in particular, should help accelerate the development of next-generation anti-C. difficile toxin therapeutics. | ||||||||||||
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構造ビューア | 分子: ![]() ![]() |
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-検証レポート
文書・要旨 | ![]() | 607.9 KB | 表示 | ![]() |
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文書・詳細版 | ![]() | 607.5 KB | 表示 | |
XML形式データ | ![]() | 29.7 KB | 表示 | |
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アーカイブディレクトリ | ![]() ![]() | HTTPS FTP |
-関連構造データ
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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: 235481.438 Da / 分子数: 1 / 由来タイプ: 組換発現 由来: (組換発現) ![]() 遺伝子: toxB, tcdB / 発現宿主: ![]() ![]() 参照: UniProt: P18177, 加水分解酵素; プロテアーゼ; ペプチド結合加水分解酵素; システインプロテアーゼ |
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#2: タンパク質 | 分子量: 34299.195 Da / 分子数: 1 / 由来タイプ: 組換発現 由来: (組換発現) ![]() ![]() 発現宿主: ![]() ![]() |
-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: ternary complex of tcdB and DLD-4 darpin / タイプ: COMPLEX / Entity ID: all / 由来: RECOMBINANT |
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由来(天然) | 生物種: ![]() |
由来(組換発現) | 生物種: ![]() ![]() |
緩衝液 | pH: 7.4 |
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: Tecnai F20 / 画像提供: FEI Company | |||||||||||||||||||||
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EM imaging |
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解析
CTF補正 | タイプ: PHASE FLIPPING AND AMPLITUDE CORRECTION |
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対称性 | 点対称性: C1 (非対称) |
3次元再構成 | 解像度: 9 Å / 解像度の算出法: FSC 0.143 CUT-OFF / 粒子像の数: 84420 / 対称性のタイプ: POINT |