In cell free system , binding of a DNA fragment containing a PPRE from __NODE__ gene and a heterodimeric protein protein complex consisting of __SP__ __NODE__ and of __NODE__ is the same as binding of a DNA fragment containing a PPRE from __NODE__ gene and a heterodimeric protein protein complex consisting of mutant __SP__ __NODE__ ( L459A E462A with its ligand binding domain mutated ) and of __NODE__ .