The TraK protein is predicted to interact with the TraV and TraB proteins as part of the scaffold which extends from the inner membrane, through the periplasm to the cell envelope and through which the F-type conjugative pilus passes. TraK is homologous to the P-type IV secretion system protein TrbG, the Ti-type protein VirB9 and the I-type TraN protein. The protein is related to the secretin family especially the HrcC subgroup of the type III secretion system. The protein is hypothesized to oligomerize to form a ring structure akin to other secretins.
Jiyao W et al.(2023). "The conserved domain database in 2023.",