This domain is found in proteins of the membrane-attack complex/ perforin (MACPF) family from Bacteroidetes. These transmembrane pore- forming proteins are organized into three structured domains: an MACPF domain (Pfam:PF01823) and two C-terminal domains, D2 and D3. This entry represents the D3 domain, which adopts an alpha/beta fold and functions as a wedge between D2 and MACPF [1].

1: Structure of a membrane-attack complex/perforin (MACPF) family protein from the human gut symbiont Bacteroides thetaiotaomicron. Xu Q, Abdubek P, Astakhova T, Axelrod HL, Bakolitsa C, Cai X, Carlton D, Chen C, Chiu HJ, Clayton T, Das D, Deller MC, Duan L, Ellrott K, Farr CL, Feuerhelm J, Grant JC, Grzechnik A, Han GW, Jaroszewski L, Jin KK, Klock HE, Knuth MW, Kozbial P, Krishna SS, Kumar A, Lam WW, Marciano D, Miller MD, Morse AT, Nigoghossian E, Nopakun A, Okach L, Puckett C, Reyes R, Tien HJ, Trame CB, van den Bedem H, Weekes D, Wooten T, Yeh A, Zhou J, Hodgson KO, Wooley J, Elsliger MA, Deacon AM, Godzik A, Lesley SA, Wilson IA; Acta Crystallogr Sect F Struct Biol Cryst Commun. 2010;66:1297-1305. PMID:20944225