In a cell free system , binding of a double stranded DNA fragment ( CTAGATGCAAAACAACTGTGACTAGTAGAACACGG ) containing a __NODE__ binding site from __NODE__ gene and __NODE__ protein is greater than binding of a double stranded DNA fragment ( CTAGATGCAAAACAACTGTGACTAGTAGAACACGG ) containing a __NODE__ binding site from __NODE__ gene and mutant __NODE__ protein ( R253S ) .