Involved in DNA transformation; mediates the nuclear uptake of single-stranded DNA copies of the transferred DNA (T-DNA) element. Binds single-stranded but not double-stranded DNA regardless of nucleotide sequence composition. Forms heterodimers with the chaperone protein virE1 that prevent virE2 anarchic homopolymerization (By similarity). Interacts with A.thaliana VIP1 that mediates its translocation to the host nucleus, and with host (e.g. A.thaliana and N.benthamiana) VIP2 that promotes T-DNA integration into the host genome. Forms a complex made of VirE2, host VIP1 and VIP2, and single-stranded DNA (ssDNA). Forms a complex made of virE2 and host (e.g. A.thaliana) proteins VIP1 and VBF. In infected cells, it is found in the nucleus. Targeted to degradation by the host proteasome by VBF and Agrobacterium virF in SCF(VBF) and SCF(COI1) E3 ubiquitin ligase complexes after mediating T-DNA translocation to the nucleus.