Download MendeleyA cysteine protease-like domain enhances the cytotoxic effects of thePhotorhabdus asymbioticatoxin PaTox.
Bogdanovic, X., Schneider, S., Levanova, N., Wirth, C., Trillhaase, C., Steinemann, M., Hunte, C., Aktories, K., Jank, T.(2019) J Biol Chem 294: 1035-1044
- PubMed: 30478175
- DOI: https://doi.org/10.1074/jbc.RA118.005043
- Primary Citation of Related Structures:
6HV6 - PubMed Abstract:
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 (PaTox P ), 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 PaTox P 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 PaTox P structure had highest similarity to that of the AvrPphB protease from Pseudomonas syringae classified as a C58-protease. Furthermore, we observed that PaTox P shares structural homology also with non-C58-cysteine proteases, deubiquitinases, and deamidases. Upon delivery into insect larvae, PaTox P alone without full-length PaTox had no toxic effects. Yet, PaTox P expression in mammalian cells was toxic and enhanced the apoptotic phenotype induced by PaTox in HeLa cells. We propose that PaTox P is a C58-like cysteine protease module that is essential for full PaTox activity.
Organizational Affiliation:
From the Institute for Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany.
