In a system of purified components , the affinity of binding of __SP__ Srebp 1a [__NODE__] protein and __NODE__ regulatory element 2 ( 5 ' AGTTTTTGATTCACCCCAGTTACT 3 ' from __SP__ __NODE__ gene is greater than the affinity of binding of __SP__ Srebp 1a [__NODE__] protein and __NODE__ regulatory element 4 ( 5 ' ACAAGACCTCTCACACAACCTCAC 3 ' from __SP__ __NODE__ gene .