In a cell free system , binding of Igf 2 [__NODE__] protein and __SP__ __NODE__ protein and __SP__ __NODE__ protein is greater than binding of Igf 2 [__NODE__] protein and __SP__ __NODE__ protein and a protein fragment ( 1 88 ) containing a N terminal domain from __NODE__ 3 [__NODE__] protein and a protein fragment ( 185 264 ) containing a C terminal domain from __SP__ __NODE__ protein .