Interaction of oxidized polyamines with DNA. I. Evidence for the formation of cross-links

U. Bachrach*, G. Eilon

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

Oxidized spermine, an aminodialdehyde obtained by the enzymic oxidation of spermine, interacts with DNA. This interaction is found to involve two classes of bonds: electrostatic binding and covalent cross-links. Gel filtration experiments show that the binding by electrostatic forces is reversible, and that DNA-oxidized spermine complexes are partially dissociated by 3 M NaCl. Urea has no effect on DNA-oxidized spermine complexes. The occurrence of covalent cross-links between the paired strands of bihelical DNA is demonstrated by thermal denaturation profiles and by sucrose gradient centrifugation of DNA-oxidized spermine complexes. Thermal denaturation profiles also confirm the importance of electrostatic bonds, which cause a shift of the 'melting temperature' of the DNA. The covalent cross-links, on the other hand, prevent strand separation, thus reducing the hyperchromic effect. It has been suggested that the electrostatic binding is due to the secondary amino groups, and the formation of cross-links to the two carbonyl groups in the molecule of oxidized spermine. Reduction of the carbonyl groups of oxidized spermine by NaBH4 abolishes the induction of cross-links. Two carbonyl groups are required for the formation of cross-links; aminomonoaldehydes, monofunctional reagents, do not induce cross-links in DNA.

Original languageEnglish
Pages (from-to)418-426
Number of pages9
JournalBBA Section Nucleic Acids And Protein Synthesis
Volume145
Issue number2
DOIs
StatePublished - 26 Sep 1967

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