In a system of purified components , the affinity of binding of a immobilized protein chimera composed of extracellular domain from __SP__ __NODE__ protein and of Fc domain from __NODE__ and a protein fragment ( 130 177 ) containing a extracellular domain from __SP__ __NODE__ protein is greater than the affinity of binding of a protein fragment ( 130 177 ) containing a extracellular domain from __SP__ __NODE__ protein and immobilized __SP__ __NODE__ protein .