In cell culture , the affinity of binding of a protein chimera composed of a protein fragment ( 1 430 ) from __SP__ __NODE__ protein and of a protein fragment ( 435 End ) from __SP__ __NODE__ protein and of a protein fragment ( QKIR ) from __SP__ __NODE__ gene and Cho cells is greater than or equal to the affinity of binding of Cho cells and __SP__ __NODE__ protein .