This family consists of several SpvD plasmid virulence proteins from different Salmonella species [1].The structure of the protein from Salmonella typhimurium has been solved and shows a papain-like fold, with a predicted catalytic triad of Cys73, His162 and Asp182. The protein has been shown to have deubiquitinating-like activity, releasing aminoluciferin (AML) from Ub-AML [2].

1: Sequence polymorphism of the Salmonella plasmid virulence factor D (SpvD) in Salmonella enterica isolates of animal origin. Bauerfeind R, Barth S, Weiss R, Baljer G; Berl Munch Tierarztl Wochenschr 2001;114:404-408. PMID:11570190

2: The Salmonella Effector SpvD Is a Cysteine Hydrolase with a Serovar-specific Polymorphism Influencing Catalytic Activity, Suppression of Immune Responses, and Bacterial Virulence. Grabe GJ, Zhang Y, Przydacz M, Rolhion N, Yang Y, Pruneda JN, Komander D, Holden DW, Hare SA; J Biol Chem. 2016;291:25853-25863. PMID:27789710