ジャーナル: Nat Commun / 年: 2020 タイトル: Antibiotic export by MexB multidrug efflux transporter is allosterically controlled by a MexA-OprM chaperone-like complex. 著者: Marie Glavier / Dhenesh Puvanendran / Dimitri Salvador / Marion Decossas / Gilles Phan / Cyril Garnier / Elisa Frezza / Quentin Cece / Guy Schoehn / Martin Picard / Jean-Christophe Taveau / ...著者: Marie Glavier / Dhenesh Puvanendran / Dimitri Salvador / Marion Decossas / Gilles Phan / Cyril Garnier / Elisa Frezza / Quentin Cece / Guy Schoehn / Martin Picard / Jean-Christophe Taveau / Laetitia Daury / Isabelle Broutin / Olivier Lambert / 要旨: The tripartite multidrug efflux system MexAB-OprM is a major actor in Pseudomonas aeruginosa antibiotic resistance by exporting a large variety of antimicrobial compounds. Crystal structures of MexB ...The tripartite multidrug efflux system MexAB-OprM is a major actor in Pseudomonas aeruginosa antibiotic resistance by exporting a large variety of antimicrobial compounds. Crystal structures of MexB and of its Escherichia coli homolog AcrB had revealed asymmetric trimers depicting a directional drug pathway by a conformational interconversion (from Loose and Tight binding pockets to Open gate (LTO) for drug exit). It remains unclear how MexB acquires its LTO form. Here by performing functional and cryo-EM structural investigations of MexB at various stages of the assembly process, we unveil that MexB inserted in lipid membrane is not set for active transport because it displays an inactive LTC form with a Closed exit gate. In the tripartite complex, OprM and MexA form a corset-like platform that converts MexB into the active form. Our findings shed new light on the resistance nodulation cell division (RND) cognate partners which act as allosteric factors eliciting the functional drug extrusion.
フィルム・検出器のモデル: GATAN K2 QUANTUM (4k x 4k) 平均電子線量: 42.0 e/Å2
電子線
加速電圧: 300 kV / 電子線源: FIELD EMISSION GUN
電子光学系
照射モード: FLOOD BEAM / 撮影モード: BRIGHT FIELD
実験機器
モデル: Titan Krios / 画像提供: FEI Company
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画像解析
粒子像選択
選択した数: 364914
CTF補正
ソフトウェア - 名称: Gctf
最終 再構成
使用したクラス数: 3 / 想定した対称性 - 点群: C1 (非対称) / 解像度のタイプ: BY AUTHOR / 解像度: 3.2 Å / 解像度の算出法: FSC 0.143 CUT-OFF 詳細: After 3D alignment on MexB, an average map was calculed from the three aligned maps and a two-by-two comparison of the maps by FSC leads to a 3.2 angstroems resolution 使用した粒子像数: 82432
初期 角度割当
タイプ: MAXIMUM LIKELIHOOD / ソフトウェア - 名称: RELION
最終 角度割当
タイプ: MAXIMUM LIKELIHOOD / ソフトウェア - 名称: RELION
最終 3次元分類
クラス数: 3 / 平均メンバー数/クラス: 27000 / ソフトウェア - 名称: RELION 詳細: Three 3D maps( calculed from Class3D and after REfine3D) were similar but show three different orientations (0,120,240 degree rotation) with respect to MexB