In __SP__ , binding of __SP__ __NODE__ protein and a protein fragment ( 91 408 ) containing a __NODE__ zipper domain 2 3 from __SP__ __NODE__ protein is greater than binding of __SP__ __NODE__ protein and a mutant protein fragment ( 91 408 ) ( L147A L148A with its __NODE__ zipper domain 2 mutated ) containing a __NODE__ zipper domain 2 3 from __SP__ __NODE__ protein .