ADP-riboxanase effector that inhibits host cell pyroptosis. Acts by mediating arginine ADP-riboxanation of host CASP4/CASP11, blocking CASP4/CASP11 autoprocessing. This prevents CASP4 activation and ability to recognize and cleave GSDMD, thereby inhibiting LPS-induced pyroptosis. ADP-riboxanation takes place in two steps: OspC3 first catalyzes ADP-ribosylation of target Arg, and then initiates a deamination to remove one N-omega group 