Preliminary chemical and X-ray studies on the interactions of E. coli DNA with putrescine.

: The interactions of E.coli DNA with putrescine in aqueous solution and fiber were studied by melting temperature analysis, equilibrium dialysis and X-ray diffraction. The equilibrium binding of putrescine to DNA is shown, of which association constant is in the order of 10(3) 1/mol. The binding of putrescine stabilizes the B-form of DNA fiber and the crossbridge of putrescine in the intra-double helix is suggested by precipitate formation experiments of various polyamines with DNA.