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-Structure paper
タイトル | and high-resolution cryo-EM structure of a bacterial type VI secretion system membrane complex. |
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ジャーナル・号・ページ | EMBO J, Vol. 38, Issue 10, Year 2019 |
掲載日 | 2019年5月15日 |
著者 | Chiara Rapisarda / Yassine Cherrak / Romain Kooger / Victoria Schmidt / Riccardo Pellarin / Laureen Logger / Eric Cascales / Martin Pilhofer / Eric Durand / Rémi Fronzes / |
PubMed 要旨 | Bacteria have evolved macromolecular machineries that secrete effectors and toxins to survive and thrive in diverse environments. The type VI secretion system (T6SS) is a contractile machine that is ...Bacteria have evolved macromolecular machineries that secrete effectors and toxins to survive and thrive in diverse environments. The type VI secretion system (T6SS) is a contractile machine that is related to phages. It is composed of a phage tail-like structure inserted in the bacterial cell envelope by a membrane complex (MC) comprising the TssJ, TssL and TssM proteins. We previously reported the low-resolution negative-stain electron microscopy structure of the enteroaggregative MC and proposed a rotational 5-fold symmetry with a TssJ:TssL:TssM stoichiometry of 2:2:2. Here, cryo-electron tomography analyses of the T6SS MC confirm the 5-fold symmetry and identify the regions of the structure that insert into the bacterial membranes. A high-resolution model obtained by single-particle cryo-electron microscopy highlights new features: five additional copies of TssJ, yielding a TssJ:TssL:TssM stoichiometry of 3:2:2, an 11-residue loop in TssM, protruding inside the lumen of the MC and constituting a functionally important periplasmic gate, and hinge regions. Based on these data, we propose an updated model on MC structure and dynamics during T6SS assembly and function. |
リンク | EMBO J / PubMed:30877094 / PubMed Central |
手法 | EM (単粒子) / EM (サブトモグラム平均) |
解像度 | 4.6 - 25.0 Å |
構造データ | EMDB-0265: EMDB-0266: EMDB-0267: EMDB-4561: EMDB-4562: |
由来 |
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キーワード | MEMBRANE PROTEIN / Membrane complex / tether |