National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R35GM144130
米国
引用
ジャーナル: Nature / 年: 2024 タイトル: Molecular insights into capsular polysaccharide secretion. 著者: Jeremi Kuklewicz / Jochen Zimmer / 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.
全体 : ABC transporter KpsMT in complex with polysaccharide co-polymeras...
全体
名称: ABC transporter KpsMT in complex with polysaccharide co-polymerase KpsE bound to the glycolipid in state 1
要素
複合体: ABC transporter KpsMT in complex with polysaccharide co-polymerase KpsE bound to the glycolipid in state 1
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超分子 #1: ABC transporter KpsMT in complex with polysaccharide co-polymeras...
超分子
名称: ABC transporter KpsMT in complex with polysaccharide co-polymerase KpsE bound to the glycolipid in state 1 タイプ: complex / ID: 1 / 親要素: 0 / 含まれる分子: #1-#3
由来(天然)
生物種: Caldimonas thermodepolymerans (バクテリア)
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実験情報
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構造解析
手法
クライオ電子顕微鏡法
解析
単粒子再構成法
試料の集合状態
particle
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試料調製
緩衝液
pH: 7.5
凍結
凍結剤: ETHANE
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電子顕微鏡法
顕微鏡
FEI TITAN KRIOS
撮影
フィルム・検出器のモデル: FEI FALCON III (4k x 4k) 平均電子線量: 50.0 e/Å2