This family is found at the N-terminus of the Tropheryma whipplei WisP family proteins ([1]).

1: Sequencing and analysis of the genome of the Whipple's disease bacterium Tropheryma whipplei. Bentley SD, Maiwald M, Murphy LD, Pallen MJ, Yeats CA, Dover LG, Norbertczak HT, Besra GS, Quail MA, Harris DE, von Herbay A, Goble A, Rutter S, Squares R, Squares S, Barrell BG, Parkhill J, Relman DA; Lancet 2003;361:637-644. PMID:12606174