Component of the type IV secretion system VirB/VirD4 which could be a major virulence determinant for subversion of human endothelial cell (HEC) function. VirB2 seems to constitute the major pilus component. Homooligomer (Potential). Interacts with the 17 kDa antigen protein that is encoded within the VirB locus (By similarity). Belongs to the virB2 family.