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 [1].

1: The structure of BVU2987 from Bacteroides vulgatus reveals a superfamily of bacterial periplasmic proteins with possible inhibitory function. Das D, Finn RD, Carlton D, Miller MD, Abdubek P, Astakhova T, Axelrod HL, Bakolitsa C, Chen C, Chiu HJ, Chiu M, Clayton T, Deller MC, Duan L, Ellrott K, Ernst D, Farr CL, Feuerhelm J, Grant JC, Grzechnik A, Han GW, Jaroszewski L, Jin KK, Klock HE, Knuth MW, Kozbial P, Krishna SS, Kumar A, Marciano D, McMullan D, Morse AT, Nigoghossian E, Nopakun A, Okach L, Puckett C, Reyes R, Rife CL, Sefcovic N, Tien HJ, Trame CB, van den Bedem H, Weekes D, Wooten T, Xu Q, Hodgson KO, Wooley J, Elsliger MA, Deacon AM, Godzik A, Lesley SA, Wilson IA; Acta Crystallogr Sect F Struct Biol Cryst Commun. 2010;66:1265-1273. PMID:20944221