The affinity of binding of __SP__ __NODE__ protein in a cell fraction from Cho cells and __SP__ __NODE__ protein in a cell fraction from Cho cells is greater than or equal to the affinity of binding of __SP__ __NODE__ protein in a system of purified components and monomeric soluble mutant __SP__ __NODE__ A protein ( deletion 474 703 with its __NODE__ type III domain 1 2 deleted and with its carboxy terminal domain and its CR domain and its linker domain 1 2 ( aa sequence __NODE__ ) and its loop domain 1 2 retained ) in a system of purified components .