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-Structure paper
タイトル | Cryo-EM structures of lipopolysaccharide transporter LptBFGC in lipopolysaccharide or AMP-PNP-bound states reveal its transport mechanism. |
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ジャーナル・号・ページ | Nat Commun, Vol. 10, Issue 1, Page 4175, Year 2019 |
掲載日 | 2019年9月13日 |
著者 | Xiaodi Tang / Shenghai Chang / Qinghua Luo / Zhengyu Zhang / Wen Qiao / Caihuang Xu / Changbin Zhang / Yang Niu / Wenxian Yang / Ting Wang / Zhibo Zhang / Xiaofeng Zhu / Xiawei Wei / Changjiang Dong / Xing Zhang / Haohao Dong / |
PubMed 要旨 | Lipopolysaccharides (LPS) of Gram-negative bacteria are critical for the defence against cytotoxic substances and must be transported from the inner membrane (IM) to the outer membrane (OM) through ...Lipopolysaccharides (LPS) of Gram-negative bacteria are critical for the defence against cytotoxic substances and must be transported from the inner membrane (IM) to the outer membrane (OM) through a bridge formed by seven membrane proteins (LptBFGCADE). The IM component LptBFG powers the process through a yet unclarified mechanism. Here we report three high-resolution cryo-EM structures of LptBFG alone and complexed with LptC (LptBFGC), trapped in either the LPS- or AMP-PNP-bound state. The structures reveal conformational changes between these states and substrate binding with or without LptC. We identify two functional transmembrane arginine-containing loops interacting with the bound AMP-PNP and elucidate allosteric communications between the domains. AMP-PNP binding induces an inward rotation and shift of the transmembrane helices of LptFG and LptC to tighten the cavity, with the closure of two lateral gates, to eventually expel LPS into the bridge. Functional assays reveal the functionality of the LptF and LptG periplasmic domains. Our findings shed light on the LPS transport mechanism. |
リンク | Nat Commun / PubMed:31519889 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 3.1 - 3.7 Å |
構造データ | EMDB-10121, PDB-6s8g: EMDB-10122, PDB-6s8h: EMDB-10125, PDB-6s8n: |
化合物 | ChemComp-ANP: ChemComp-LMD: ChemComp-LMN: ChemComp-JSG: ChemComp-DCQ: ChemComp-LMT: ChemComp-L0W: |
由来 |
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キーワード | TRANSPORT PROTEIN (運搬体タンパク質) / lipopolysaccharide transporter / LPS / LptB2FGC / LptB (ロンドン旅客運輸公社) / LptBFG / outer membrane / Gram-negative bacteria (グラム陰性菌) / ABC transporter / Inner membrane protein complex |