This domain family is found in bacteria, and is approximately 90 amino acids in length. The family is found to the C-terminus of Pfam:PF00823. There is a conserved SVP sequence motif which is diagnostic of this subfamily [2]. There is a single completely conserved residue W that may be functionally important. The proteins in this family are PPE proteins implicated in immunostimulation and virulence.

1: Genomic comparison of PE and PPE genes in the Mycobacterium avium complex. Mackenzie N, Alexander DC, Turenne CY, Behr MA, De Buck JM; J Clin Microbiol. 2009;47:1002-1011. PMID:19144814

2: Evolution and expansion of the Mycobacterium tuberculosis PE and PPE multigene families and their association with the duplication of the ESAT-6 (esx) gene cluster regions. Gey van Pittius NC, Sampson SL, Lee H, Kim Y, van Helden PD, Warren RM; BMC Evol Biol. 2006;6:95. PMID:17105670