This domain is found in Legionella ubiquitin-specific protease A (LupA). LupA removes a ubiquitin modification from LegC3 which inactivates the cognate effector. This domain is typical of eukaryotic ubiquitin proteases involved in deconjugation of ubiquitin or ubiquitin-like proteins from their targets [1].

1: Diverse mechanisms of metaeffector activity in an intracellular bacterial pathogen, Legionella pneumophila. Urbanus ML, Quaile AT, Stogios PJ, Morar M, Rao C, Di Leo R, Evdokimova E, Lam M, Oatway C, Cuff ME, Osipiuk J, Michalska K, Nocek BP, Taipale M, Savchenko A, Ensminger AW; Mol Syst Biol. 2016;12:893. PMID:27986836