In a system of purified components , the affinity of binding of __SP__ __NODE__ protein and mutant __SP__ __NODE__ protein ( N150H K154T Q319L M354I ) is greater than the affinity of binding of mutant __SP__ __NODE__ protein ( R201A K202A K206A R207A K208A K211A R214A R216A K217A R218A ) and mutant __SP__ __NODE__ protein ( N150H K154T Q319L M354I ) .