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-Structure paper
タイトル | Structural basis for lipid and copper regulation of the ABC transporter MsbA. |
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ジャーナル・号・ページ | Nat Commun, Vol. 13, Issue 1, Page 7291, Year 2022 |
掲載日 | 2022年11月26日 |
著者 | Jixing Lyu / Chang Liu / Tianqi Zhang / Samantha Schrecke / Nicklaus P Elam / Charles Packianathan / Georg K A Hochberg / David Russell / Minglei Zhao / Arthur Laganowsky / |
PubMed 要旨 | A critical step in lipopolysaccharide (LPS) biogenesis involves flipping lipooligosaccharide, an LPS precursor, from the cytoplasmic to the periplasmic leaflet of the inner membrane, an operation ...A critical step in lipopolysaccharide (LPS) biogenesis involves flipping lipooligosaccharide, an LPS precursor, from the cytoplasmic to the periplasmic leaflet of the inner membrane, an operation carried out by the ATP-binding cassette transporter MsbA. Although LPS binding to the inner cavity of MsbA is well established, the selectivity of MsbA-lipid interactions at other site(s) remains poorly understood. Here we use native mass spectrometry (MS) to characterize MsbA-lipid interactions and guide structural studies. We show the transporter co-purifies with copper(II) and metal binding modulates protein-lipid interactions. A 2.15 Å resolution structure of an N-terminal region of MsbA in complex with copper(II) is presented, revealing a structure reminiscent of the GHK peptide, a high-affinity copper(II) chelator. Our results demonstrate conformation-dependent lipid binding affinities, particularly for the LPS-precursor, 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo)-lipid A (KDL). We report a 3.6 Å-resolution structure of MsbA trapped in an open, outward-facing conformation with adenosine 5'-diphosphate and vanadate, revealing a distinct KDL binding site, wherein the lipid forms extensive interactions with the transporter. Additional studies provide evidence that the exterior KDL binding site is conserved and a positive allosteric modulator of ATPase activity, serving as a feedforward activation mechanism to couple transporter activity with LPS biosynthesis. |
リンク | Nat Commun / PubMed:36435815 / PubMed Central |
手法 | EM (単粒子) / X線回折 |
解像度 | 2.15 - 3.9 Å |
構造データ | EMDB-27544, PDB-8dmm: EMDB-27545, PDB-8dmo: PDB-8dhy: |
化合物 | ChemComp-CU: ChemComp-HOH: ChemComp-AOV: ChemComp-KDL: |
由来 |
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キーワード | FLUORESCENT PROTEIN / copper binding / MsbA / TRANSPORT PROTEIN / ABC transporter |