The DNA polymerase processivity factor (UL42) of Human herpesvirus 1 (HHV-1) forms a heterodimer with UL30 to create the viral DNA polymerase complex. UL42 functions to increase the processivity of polymerisation and makes little contribution to the catalytic activity of the polymerase.
Zuccola HJ, Filman DJ, Coen DM, Hogle JM.
The crystal structure of an unusual processivity factor, herpes simplex virus UL42, bound to the C terminus of its cognate polymerase.
Mol. Cell 5 2000 267-78
[PubMed: 10882068] http://dx.doi.org/10.1016/S1097-2765(00)80422-0