In a cell free system , the affinity of binding of __SP__ __NODE__ protein and __SP__ __NODE__ protein and non glycosylated mutant __SP__ __NODE__ protein ( N89A N109A N172A with its repeated ( 3 times ) N glycosylation site mutated ) is the same as the affinity of binding of __SP__ __NODE__ protein and __SP__ __NODE__ protein and __SP__ __NODE__ protein .