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-Structure paper
タイトル | Molecular insights into capsular polysaccharide secretion. |
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ジャーナル・号・ページ | Nature, Vol. 628, Issue 8009, Page 901-909, Year 2024 |
掲載日 | 2024年4月3日 |
著者 | Jeremi Kuklewicz / Jochen Zimmer / |
PubMed 要旨 | Capsular polysaccharides (CPSs) fortify the cell boundaries of many commensal and pathogenic bacteria. Through the ABC-transporter-dependent biosynthesis pathway, CPSs are synthesized intracellularly ...Capsular polysaccharides (CPSs) fortify the cell boundaries of many commensal and pathogenic bacteria. Through the ABC-transporter-dependent biosynthesis pathway, CPSs are synthesized intracellularly on a lipid anchor and secreted across the cell envelope by the KpsMT ABC transporter associated with the KpsE and KpsD subunits. Here we use structural and functional studies to uncover crucial steps of CPS secretion in Gram-negative bacteria. We show that KpsMT has broad substrate specificity and is sufficient for the translocation of CPSs across the inner bacterial membrane, and we determine the cell surface organization and localization of CPSs using super-resolution fluorescence microscopy. Cryo-electron microscopy analyses of the KpsMT-KpsE complex in six different states reveal a KpsE-encaged ABC transporter, rigid-body conformational rearrangements of KpsMT during ATP hydrolysis and recognition of a glycolipid inside a membrane-exposed electropositive canyon. In vivo CPS secretion assays underscore the functional importance of canyon-lining basic residues. Combined, our analyses suggest a molecular model of CPS secretion by ABC transporters. |
リンク | Nature / PubMed:38570679 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 3.1 - 4.4 Å |
構造データ | EMDB-41592, PDB-8tsh: EMDB-41593, PDB-8tsi: EMDB-41595, PDB-8tsl: EMDB-41601, PDB-8tsw: EMDB-41602, PDB-8tt3: EMDB-41626, PDB-8tun: EMDB-41677: S. thermodepolymerans KpsMT-KpsE Apo 1 - consensus map EMDB-41678: S. thermodepolymerans KpsMT-KpsE Apo 1 - KpsT-focused map EMDB-41681: S. thermodepolymerans KpsMT(E151Q)-KpsE in complex with ATP - consensus map EMDB-41682: S. thermodepolymerans KpsMT(E151Q)-KpsE in complex with ATP - crown focused map EMDB-41697: S. thermodepolymerans KpsMT-KpsE in Apo 2 state - consensus map EMDB-41698: S. thermodepolymerans KpsMT-KpsE in Apo 2 state - KpsT focused map EMDB-41718: S. thermodepolymerans KpsMT-KpsE with bound glycolipid - state 1 - consensus map EMDB-41720: S. thermodepolymerans KpsMT-KpsE with bound glycolipid - state 1 - KpsT focused map EMDB-41721: S. thermodepolymerans KpsMT-KpsE with bound glycolipid - state 1 - KpsM focused map EMDB-41771: S. thermodepolymerans KpsMT-KpsE with bound glycolipid - state 2 - consensus map EMDB-41772: S. thermodepolymerans KpsMT-KpsE with bound glycolipid - state 2 - KpsT focused map EMDB-41773: S. thermodepolymerans KpsMT-KpsE with bound glycolipid - state 2 - KpsM focused map |
化合物 | ChemComp-ATP: ChemComp-MG: ChemComp-ADP: ChemComp-ALF:
ChemComp-KJ9: |
由来 |
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キーワード | MEMBRANE PROTEIN / ABC transporter / Capsular polysaccharide |