Download MendeleyCryo-EM reveals species-specific components within the Helicobacter pylori Cag type IV secretion system core complex.
Sheedlo, M.J., Chung, J.M., Sawhney, N., Durie, C.L., Cover, T.L., Ohi, M.D., Lacy, D.B.(2020) Elife 9
- PubMed: 32876048
- DOI: https://doi.org/10.7554/eLife.59495
- Primary Citation of Related Structures:
6X6J, 6X6K, 6X6L, 6X6S - PubMed Abstract:
The pathogenesis of Helicobacter pylori -associated gastric cancer is dependent on delivery of CagA into host cells through a type IV secretion system (T4SS). The H. pylori Cag T4SS includes a large membrane-spanning core complex containing five proteins, organized into an outer membrane cap (OMC), a periplasmic ring (PR) and a stalk. Here, we report cryo-EM reconstructions of a core complex lacking Cag3 and an improved map of the wild-type complex. We define the structures of two unique species-specific components (Cag3 and CagM) and show that Cag3 is structurally similar to CagT. Unexpectedly, components of the OMC are organized in a 1:1:2:2:5 molar ratio (CagY:CagX:CagT:CagM:Cag3). CagX and CagY are components of both the OMC and the PR and bridge the symmetry mismatch between these regions. These results reveal that assembly of the H. pylori T4SS core complex is dependent on incorporation of interwoven species-specific components.
Organizational Affiliation:
Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, United States.
