Conjugative DNA transfer (CDT) is the unidirectional transfer of ssDNA plasmid from a donor to a recipient cell. It is the central mechanism by which antibiotic resistance and virulence factors are propagated in bacterial populations. Part of the relaxosome, which facilitates a site- and strand-specific cut in the origin of transfer by TraI, at the nic site. Relaxosome formation requires binding of IHF and TraY to the oriT region, which then facilitates binding of TraI. Also positively regulates tra gene expression (By similarity). Part of the relaxosome, a complex composed of plasmid encoded TraI, TraM, TraY and host-encoded IHF bound to the F plasmid origin of transfer (oriT). Interacts with TraM, probably through its C-terminus (By similarity). Belongs to the TraY family.