Structural insights into the assembly pathway of the Helicobacter pylori CagT4SS outer membrane core complex

IF 4.4 2区生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY

Structure Pub Date : 2024-07-19 DOI:10.1016/j.str.2024.06.019

引用次数: 0

Abstract

Cag type IV secretion system (CagT4SS) translocates oncoprotein cytotoxin-associated gene A (CagA) into host cells and plays a key role in the pathogenesis of Helicobacter pylori. The structure of the outer membrane core complex (OMCC) in CagT4SS consists of CagX, CagY, CagM, CagT, and Cag3 in a stoichiometric ratio of 1:1:2:2:5 with 14-fold symmetry. However, the assembly pathway of OMCC remains elusive. Here, we report the crystal structures of CagT and Cag3-CagT complex, and the structural dynamics of Cag3 and CagT using hydrogen deuterium exchange-mass spectrometry (HDX-MS). The interwoven interaction of Cag3 and CagT involves conformational changes of CagT and β strand swapping. In conjunction with biochemical and biophysical assays, we further demonstrate the different oligomerization states of Cag3 and Cag3-CagT complex. Additionally, the association with CagM requires the pre-formation of Cag3-CagT complex. These results demonstrate the generation of different intermediate sub-assemblies and their structural flexibility, potentially representing different building blocks for OMCC assembly.

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幽门螺杆菌 CagT4SS 外膜核心复合物组装途径的结构启示

Cag IV型分泌系统（CagT4SS）将肿瘤蛋白细胞毒素相关基因A（CagA）转运到宿主细胞中，在幽门螺旋杆菌的致病过程中发挥着关键作用。CagT4SS 的外膜核心复合物（OMCC）结构由 CagX、CagY、CagM、CagT 和 Cag3 组成，其化学计量比为 1:1:2:2:5，具有 14 倍对称性。然而，OMCC 的组装途径仍然难以捉摸。在此，我们报告了 CagT 和 Cag3-CagT 复合物的晶体结构，并利用氢氘交换质谱（HDX-MS）分析了 Cag3 和 CagT 的结构动态。Cag3和CagT的交织相互作用涉及CagT的构象变化和β链交换。结合生化和生物物理实验，我们进一步证明了 Cag3 和 Cag3-CagT 复合物的不同寡聚状态。此外，与 CagM 的结合需要 Cag3-CagT 复合物的预形成。这些结果证明了不同中间亚组装的产生及其结构的灵活性，它们可能代表了 OMCC 组装的不同构件。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Structure 生物-生化与分子生物学

CiteScore

8.90

自引率

1.80%

发文量

155

审稿时长

3-8 weeks

期刊介绍： Structure aims to publish papers of exceptional interest in the field of structural biology. The journal strives to be essential reading for structural biologists, as well as biologists and biochemists that are interested in macromolecular structure and function. Structure strongly encourages the submission of manuscripts that present structural and molecular insights into biological function and mechanism. Other reports that address fundamental questions in structural biology, such as structure-based examinations of protein evolution, folding, and/or design, will also be considered. We will consider the application of any method, experimental or computational, at high or low resolution, to conduct structural investigations, as long as the method is appropriate for the biological, functional, and mechanistic question(s) being addressed. Likewise, reports describing single-molecule analysis of biological mechanisms are welcome. In general, the editors encourage submission of experimental structural studies that are enriched by an analysis of structure-activity relationships and will not consider studies that solely report structural information unless the structure or analysis is of exceptional and broad interest. Studies reporting only homology models, de novo models, or molecular dynamics simulations are also discouraged unless the models are informed by or validated by novel experimental data; rationalization of a large body of existing experimental evidence and making testable predictions based on a model or simulation is often not considered sufficient.