The reaction of deoxyribose dinucleoside monophosphate, (dCpG) with cisplatin and platinum(Ⅱ) bis(2-phenylpyridine)-2, 2-bipyridine and palladium (II) bis(2-phenylpyridine)-2, 2'-bipyridine in several pH solutions (pH 2, 7,11) have been studied. Cir...
The reaction of deoxyribose dinucleoside monophosphate, (dCpG) with cisplatin and platinum(Ⅱ) bis(2-phenylpyridine)-2, 2-bipyridine and palladium (II) bis(2-phenylpyridine)-2, 2'-bipyridine in several pH solutions (pH 2, 7,11) have been studied. Circular dichroism (CD) analysis has been used to characterize the complex formed. As in the case of GpC, d(CpG) appears as an N(7)-N(3) platinum chelate, the CD of which supports a left-handed helical arrangement of the bases. Their CD spectra exhibit an increase of ellipticity in the 275-nm region, which can be qualitatively related to the characteristic increase reported for platinated DNA and ploy(dG) ·ploy(dC). These results are in favor of the hypothesis of intrastrand cross-linking of adjacent guanines, by the cis-Pt(II)(NH_3)_2 moiety, after a local denaturation of DNA.