In a cell free system , binding of 120 kd __SP__ __NODE__ protein from lysate IB4 cells and a protein fragment ( 427 483 ) from HHV4 viral Ebna2 protein is greater than binding of 120 kd __SP__ __NODE__ protein from lysate IB4 cells and a mutant protein fragment ( 427 483 ) ( W454T ) from HHV4 viral Ebna2 protein .