VirB8 is a bacterial virulence protein with cytoplasmic, transmembrane, and periplasmic regions. It is thought that it is a primary constituent of a DNA transporter. The periplasmic region interacts with VirB9, VirB10, and itself. This family also includes the conjugal transfer protein family TrbF, a family of proteins known to be involved in conjugal transfer. The TrbF protein is thought to compose part of the pilus required for transfer. This domain has a similar fold to the NTF2 protein.