Legionella pneumophila causes a severe pneumonia known as Legionnaires’ disease. During the infection, Legionella injects more than 300 effector proteins into host cells. Among them are enzymes involved in altering the host-ubiquitination system. Here, we identified two LegionellaOTU (ovarian tumor)-like deubiquitinases (LOT-DUBs; LotB [Lpg1621/Ceg23] and LotC [Lpg2529]). The crystal structure of the LotC catalytic core (LotC14-310 ) was determined at 2.4 Å. Unlike the classical OTU-family, the LOT-family shows an extended helical lobe between the Cys-loop and the variable loop, which defines them as a unique class of OTU-DUBs. LotB has an additional ubiquitin-binding site (S1’), which enables the specific cleavage of Lys63-linked polyubiquitin chains. By contrast, LotC only contains the S1 site and cleaves different species of ubiquitin chains. MS analysis of LotB and LotC identified different categories of host-interacting proteins and substrates. Together, our results provide new structural insights into bacterial OTU-DUBs and indicate distinct roles in host–pathogen interactions.
Bibliographical noteFunding Information:
We thank Yuxin-Mao for providing SidC and SdcA clones. We also thank Andrea Gubas for critical reading and Stefan Knapp for the advice in structure determination and sharing synchrotron time. The authors also thank the staff at SLS for their support during crystallographic X-ray diffraction data collection. The data collection at SLS has been supported by the funding from the European Union’s Horizon 2020 research and innovation program under grant agreement number 730872, project CALIPSOplus. This project was supported by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (ID, grant agreement No 742720), the LOEWE program DynaMem of the State of Hesse (Germany, Project-ID III L6-519/03/03.001 – ), and Deutsche Forschungsgemeinschaft (DFG, German Research Foundation Project-ID 259130777 – SFB1177; Leibniz-Program to ID; CEF-MC - EXC115/2; SFB 902), the Max Planck Society and NWO-VIDI grant and Off-rad grant for G.H.
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All Science Journal Classification (ASJC) codes
- Immunology and Microbiology(all)
- Biochemistry, Genetics and Molecular Biology(all)