A cysteine protease–like domain enhances the cytotoxic effects of the Photorhabdus asymbiotica toxin PaTox
| Autor: | Nadezhda Levanova, Xenia Bogdanović, Christoph Trillhaase, Silvia Schneider, Christophe Wirth, Marcus Steinemann, Carola Hunte, Thomas Jank, Klaus Aktories |
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| Rok vydání: | 2019 |
| Předmět: |
0301 basic medicine
Proteases Protease 030102 biochemistry & molecular biology Chemistry Effector medicine.medical_treatment Cell Biology Biochemistry Cysteine protease 03 medical and health sciences 030104 developmental biology Heterotrimeric G protein Catalytic triad medicine Oxyanion hole Molecular Biology Cysteine |
| Zdroj: | Journal of Biological Chemistry. 294:1035-1044 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.ra118.005043 |
| Popis: | The nematode mutualistic bacterium Photorhabdus asymbiotica produces a large virulence-associated multifunctional protein toxin named PaTox. A glycosyltransferase domain and a deamidase domain of this large toxin function as effectors that specifically target host Rho GTPases and heterotrimeric G proteins, respectively. Modification of these intracellular regulators results in toxicity toward insects and mammalian cells. In this study, we identified a cysteine protease–like domain spanning PaTox residues 1844–2114 (PaToxP), upstream of these two effector domains and characterized by three conserved amino acid residues (Cys-1865, His-1955, and Asp-1975). We determined the crystal structure of the PaToxP C1865A variant by native single-wavelength anomalous diffraction of sulfur atoms (sulfur-SAD). At 2.0 Å resolution, this structure revealed a catalytic site typical for papain-like cysteine proteases, comprising a catalytic triad, oxyanion hole, and typical secondary structural elements. The PaToxP structure had highest similarity to that of the AvrPphB protease from Pseudomonas syringae classified as a C58-protease. Furthermore, we observed that PaToxP shares structural homology also with non–C58-cysteine proteases, deubiquitinases, and deamidases. Upon delivery into insect larvae, PaToxP alone without full-length PaTox had no toxic effects. Yet, PaToxP expression in mammalian cells was toxic and enhanced the apoptotic phenotype induced by PaTox in HeLa cells. We propose that PaToxP is a C58-like cysteine protease module that is essential for full PaTox activity. |
| Databáze: | OpenAIRE |
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