TraF protein undergoes proteolytic processing associated with export. The 19 amino acids at the amino terminus of the polypeptides appear to constitute a typical membrane leader peptide - not included in this family, while the remainder of the molecule is predicted to be primarily hydrophilic in character [1]. F plasmid TraF and TraH are required for F pilus assembly and F plasmid transfer, and they are both localised to the outer membrane in the presence of the complete F transfer region, especially TraV, the putative anchor [2].

1: The product of the F plasmid transfer operon gene, traF, is a periplasmic protein. Wu JH, Kathir P, Ippen-Ihler K; J Bacteriol. 1988;170:3633-3639. PMID:3042757

2: F plasmid TraF and TraH are components of an outer membrane complex involved in conjugation. Arutyunov D, Arenson B, Manchak J, Frost LS; J Bacteriol. 2010;192:1730-1734. PMID:20081027