- EMDB-8860: Cryo-EM structure of the T2SS secretin XcpQ from Pseudomonas aeru... -
+
データを開く
IDまたはキーワード:
読み込み中...
-
基本情報
登録情報
データベース: EMDB / ID: EMD-8860
タイトル
Cryo-EM structure of the T2SS secretin XcpQ from Pseudomonas aeruginosa
マップデータ
T2SS secretin XcpQ from Pseudomonas aeruginosa
試料
複合体: Type 2 secretion system outer membrane secretin XcpQ
タンパク質・ペプチド: Type II secretion system protein D
キーワード
T2SS / Secretin / Type 2 secretion system / Pentadecamer / GspD / XcpQ / MEMBRANE PROTEIN
機能・相同性
機能・相同性情報
protein secretion by the type II secretion system / type II protein secretion system complex / protein secretion / cell outer membrane / identical protein binding 類似検索 - 分子機能
Type II secretion system protein GspD / : / GspD-like, N0 domain / GspD/PilQ family / Bacterial type II secretion system protein D signature. / Type II secretion system protein GspD, conserved site / : / NolW-like / NolW-like superfamily / Bacterial type II/III secretion system short domain ...Type II secretion system protein GspD / : / GspD-like, N0 domain / GspD/PilQ family / Bacterial type II secretion system protein D signature. / Type II secretion system protein GspD, conserved site / : / NolW-like / NolW-like superfamily / Bacterial type II/III secretion system short domain / Type II/III secretion system / Bacterial type II and III secretion system protein 類似検索 - ドメイン・相同性
National Health and Medical Research Council (NHMRC, Australia)
1092262
オーストラリア
Australian Research Council (ARC)
FL130100038).
オーストラリア
引用
ジャーナル: mBio / 年: 2017 タイトル: Structural Basis of Type 2 Secretion System Engagement between the Inner and Outer Bacterial Membranes. 著者: Iain D Hay / Matthew J Belousoff / Trevor Lithgow / 要旨: Sophisticated nanomachines are used by bacteria for protein secretion. In Gram-negative bacteria, the type 2 secretion system (T2SS) is composed of a pseudopilus assembly platform in the inner ...Sophisticated nanomachines are used by bacteria for protein secretion. In Gram-negative bacteria, the type 2 secretion system (T2SS) is composed of a pseudopilus assembly platform in the inner membrane and a secretin complex in the outer membrane. The engagement of these two megadalton-sized complexes is required in order to secrete toxins, effectors, and hydrolytic enzymes. has at least two T2SSs, with the ancestral nanomachine having a secretin complex composed of XcpQ. Until now, no high-resolution structural information was available to distinguish the features of this -type secretin, which varies greatly in sequence from the well-characterized -type and -type secretins. We have purified the ~1-MDa secretin complex and analyzed it by cryo-electron microscopy. Structural comparisons with the -type secretin complex revealed a striking structural homology despite the differences in their sequence characteristics. At 3.6-Å resolution, the secretin complex was found to have 15-fold symmetry throughout the membrane-embedded region and through most of the domains in the periplasm. However, the N1 domain and N0 domain were not well ordered into this 15-fold symmetry. We suggest a model wherein this disordering of the subunit symmetry for the periplasmic N domains provides a means to engage with the 6-fold symmetry in the inner membrane platform, with a metastable engagement that can be disrupted by substrate proteins binding to the region between XcpP, in the assembly platform, and the XcpQ secretin. How the outer membrane and inner membrane components of the T2SS engage each other and yet can allow for substrate uptake into the secretin chamber has challenged the protein transport field for some time. This vexing question is of significance because the T2SS collects folded protein substrates in the periplasm for transport out of the bacterium and yet must discriminate these few substrate proteins from all the other hundred or so folded proteins in the periplasm. The structural analysis here supports a model wherein substrates must compete against a metastable interaction between XcpP in the assembly platform and the XcpQ secretin, wherein only structurally encoded features in the T2SS substrates compete well enough to disrupt XcpQ-XcpP for entry into the XcpQ chamber, for secretion across the outer membrane.