This family of bacterial proteins is probably periplasmic. Members are found predominantly in microbes of the human gut and oral cavity. Structurally, one member of this family is found to show similarity to the beta-lactamase-inhibitor PepSY proteins, so the overall function may be inhibitory. There are tandem repeats of the domain on many family members.
Jiyao W et al.(2023). "The conserved domain database in 2023.",