Interaction of cis- and trans-dichlorodiammineplatinum(II) with synthetic polydeoxyribonucleotides: Effect on equilibrium buoyant densities

David E. Amacher, Michael W. Lieberman

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

Equilibrium buoyant densities in Cs2SO4 of four synthetic double-stranded polydeoxyribonucleotides were compared following reaction with either cis-Pt(NH3)2Cl2, trans-Pt(NH3)2Cl2 or PtCl4. While both Pt(NH3)2Cl2 isomers caused significant increases in the buoyant densities (ρ{variant}) of the two G + C polymers, the cis- isomer increased the ρ{variant} of poly[d(G-C)] and the trans- isomer increased the ρ{variant} of poly(dG) · poly(dC) more sharply than the corresponding isomer at low molar ratios of metal ion to polymer. Chloroplatinic acid was without effect. Only cis-Pt(NH3)2Cl2 produced substantial increases in the ρ{variant} of poly[d(A-T)] and poly(dA) · poly(dT) with increasing metal ion concentrations. These increases were accompanied by a proportional decrease in the thermal transition temperature (Tm) of poly(dA)-poly(dT) and a sharp increase in the Tm of poly[d(A-T)]. Our results indicate that the cis- isomer reacts with all four polymers to produce ρ{variant} changes clearly distinct from those values observed after reaction with either the trans- isomer or PtCl4. These results help explain the observation by others that the cis- isomer produces greater ρ{variant} changes in native DNA than the trans- isomer. On the basis of our data and the published results of others, one may rationalize the quantitative differences between the cis- and trans- compounds on the buoyant densities of naturally occurring DNA; however, additional studies are clearly needed.

Original languageEnglish (US)
Pages (from-to)265-273
Number of pages9
JournalChemico-Biological Interactions
Volume16
Issue number3
DOIs
StatePublished - Jan 1 1977

ASJC Scopus subject areas

  • Toxicology

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