In a cell free system , the affinity of binding of a DNA fragment ( GATCCCACTGGCACACAAAATGTGCAGCCAGCAG ) containing a GRE 1 from __NODE__(s) and __SP__ __NODE__ protein is greater than the affinity of binding of a DNA fragment ( GATCCAGCCAGCAGCATATGAAGTCCAAGAGGCG ) containing a GRE 2 from __NODE__(s) and __SP__ __NODE__ protein .