This family contains bacterial TraD conjugal transfer proteins [1]. Mutations in the TraD gene result in loss of transfer [2].

1: The tra region of the nopaline-type Ti plasmid is a chimera with elements related to the transfer systems of RSF1010, RP4, and F. Farrand SK, Hwang I, Cook DM; J Bacteriol 1996;178:4233-4247. PMID:8763953

2: Genetic and structural analysis of the Bacteroides conjugative transposon CTn341. Bacic M, Parker AC, Stagg J, Whitley HP, Wells WG, Jacob LA, Smith CJ; J Bacteriol. 2005;187:2858-2869. PMID:15805532