6MI7

Nucleotide-free Cryo-EM Structure of E.coli LptB2FGC

6MI7 の概要

• エントリーDOI: 10.2210/pdb6mi7/pdb
• EMDBエントリー: 9118 9125
• 分子名称: Lipopolysaccharide export system permease protein LptF, Lipopolysaccharide export system permease protein LptG, Lipopolysaccharide export system ATP-binding protein LptB, ... (5 entities in total)
• 機能のキーワード: abc transporter, lipopolysaccharide, lps, nanodisc, membrane protein, hydrolase-transport protein complex, hydrolase/transport protein
• 由来する生物種: Escherichia coli (strain K12); 詳細
• タンパク質・核酸の鎖数: 5
• 化学式量合計: 160866.96

構造登録者

Orlando, B.J.,Li, Y.,Liao, M. (登録日: 2018-09-19, 公開日: 2019-04-03, 最終更新日: 2025-06-04)

主引用文献

Li, Y.,Orlando, B.J.,Liao, M.
Structural basis of lipopolysaccharide extraction by the LptB2FGC complex.
Nature, 567:486-490, 2019

PubMed Abstract: In Gram-negative bacteria, lipopolysaccharide is essential for outer membrane formation and antibiotic resistance. The seven lipopolysaccharide transport (Lpt) proteins A-G move lipopolysaccharide from the inner to the outer membrane. The ATP-binding cassette transporter LptBFG, which tightly associates with LptC, extracts lipopolysaccharide out of the inner membrane. The mechanism of the LptBFG-LptC complex (LptBFGC) and the role of LptC in lipopolysaccharide transport are poorly understood. Here we characterize the structures of LptBFG and LptBFGC in nucleotide-free and vanadate-trapped states, using single-particle cryo-electron microscopy. These structures resolve the bound lipopolysaccharide, reveal transporter-lipopolysaccharide interactions with side-chain details and uncover how the capture and extrusion of lipopolysaccharide are coupled to conformational rearrangements of LptBFGC. LptC inserts its transmembrane helix between the two transmembrane domains of LptBFG, which represents a previously unknown regulatory mechanism for ATP-binding cassette transporters. Our results suggest a role for LptC in achieving efficient lipopolysaccharide transport, by coordinating the action of LptBFG in the inner membrane and Lpt protein interactions in the periplasm.

PubMed: 30894744
DOI: 10.1038/s41586-019-1025-6

実験手法

ELECTRON MICROSCOPY (4.2 Å)