The substrate specificity switch FlhB assembles onto the export gate to regulate type three secretion
| Autor: | Joseph J. E. Caesar, Andreas Zeitler, Samuel Wagner, Joseph Fisher, Sandra Bäurle, Lucas Kuhlen, Justin C. Deme, Susan M. Lea, Rebecca Debo, Steven Johnson |
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| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
0301 basic medicine
Models Molecular Science 030106 microbiology Protein domain General Physics and Astronomy Gating Flagellum General Biochemistry Genetics and Molecular Biology Article Protein Structure Secondary Substrate Specificity 03 medical and health sciences Protein structure Bacterial Proteins Protein Domains Cryoelectron microscopy Escherichia coli Secretion lcsh:Science Bacterial Secretion Systems Vibrio Multidisciplinary Chemistry General Chemistry Periplasmic space 3. Good health Transport protein Transmembrane domain Protein Transport 030104 developmental biology Biophysics lcsh:Q Pathogens Structural biology Hydrophobic and Hydrophilic Interactions |
| Zdroj: | Nature Communications, Vol 11, Iss 1, Pp 1-10 (2020) Nature Communications |
| ISSN: | 2041-1723 |
| DOI: | 10.1038/s41467-020-15071-9 |
| Popis: | Protein secretion through type-three secretion systems (T3SS) is critical for motility and virulence of many bacteria. Proteins are transported through an export gate containing three proteins (FliPQR in flagella, SctRST in virulence systems). A fourth essential T3SS protein (FlhB/SctU) functions to “switch” secretion substrate specificity once the growing hook/needle reach their determined length. Here, we present the cryo-electron microscopy structure of an export gate containing the switch protein from a Vibrio flagellar system at 3.2 Å resolution. The structure reveals that FlhB/SctU extends the helical export gate with its four predicted transmembrane helices wrapped around FliPQR/SctRST. The unusual topology of the FlhB/SctU helices creates a loop wrapped around the bottom of the closed export gate. Structure-informed mutagenesis suggests that this loop is critical in gating secretion and we propose that a series of conformational changes in the T3SS trigger opening of the gate through interactions between FlhB/SctU and FliPQR/SctRST. Export of proteins by type three secretion systems occurs through an export gate that is localized in the periplasm. Here, the authors present the cryo-EM structure of the Vibrio mimicus export gate complex with FlhB, which plays a major role in switching of the specificity of secretion substrates and propose a mechanism for export gate opening. |
| Databáze: | OpenAIRE |
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