Charge dependence of Fe(II)-catalyzed DNA cleavage

Min Lu, Qiu Guo, Donald J. Wink, Neville R. Kallenbach

Research output: Contribution to journalArticle

Abstract

The effect of charge of the Fe(II) reagent used to induce DNA strand cleavage reactions in the presence of a source of reducing equivalents is investigated using two oligonucleotide models. The first consists of the two strands dA20 and dT20, and an equimolar complex between them. The second is a short four-arm branched DNA complex composed of four 16-mer strands. In the former case, cleavage of the 1:1 complex by three reagents with different formal charge, Fe(II)·EDTA2-, Fe(II)-EDDA and Fe2+, is comparable in rate to that of the individual dT20 and the dA20 strands. While the three reagents show similar cleavage rates for the duplex and single stranded molecules, they give distinctive cutting patterns in the DNA tetramer, consistent with the presence of a site of excess negative charge at the branch point. Scission induced by Fe(II)·EDTA2- shows lower reactivity at the branch site relative to duplex controls, whereas Fe(II)2+ shows enhanced reactivity. Formally neutral Fe(II)·EDDA shows weak loss of cutting reactivity at the branch. The position of attack by Fe(II)2+ in the branched tetramer is shifted with respect to those of Fe(II)·EDTA2- or Fe(II)·EDDA; a slower migrating species is also detected in the scission of dA20·dT20 duplex by Fe(II) reaction. These results suggest that the Fe(II)2+ reaction proceeds by a different mechanism from the other agents. The difference in cutting profiles induced by the neutral and negatively charged chelated complexes is consistent with a local electrostatic repulsion of a negatively charged source of radicals, not a positively charged one.

Original languageEnglish (US)
Pages (from-to)3333-3337
Number of pages5
JournalNucleic Acids Research
Volume18
Issue number11
StatePublished - Jun 11 1990

Fingerprint

DNA Cleavage
Reactivity
DNA
Charge
Branch
Oligonucleotides
Static Electricity
Branch Point
Electrostatics
Excess
Molecules
Attack
EDDA

ASJC Scopus subject areas

  • Genetics
  • Statistics, Probability and Uncertainty
  • Applied Mathematics
  • Health, Toxicology and Mutagenesis
  • Toxicology
  • Genetics(clinical)

Cite this

Lu, M., Guo, Q., Wink, D. J., & Kallenbach, N. R. (1990). Charge dependence of Fe(II)-catalyzed DNA cleavage. Nucleic Acids Research, 18(11), 3333-3337.

Charge dependence of Fe(II)-catalyzed DNA cleavage. / Lu, Min; Guo, Qiu; Wink, Donald J.; Kallenbach, Neville R.

In: Nucleic Acids Research, Vol. 18, No. 11, 11.06.1990, p. 3333-3337.

Research output: Contribution to journalArticle

Lu, M, Guo, Q, Wink, DJ & Kallenbach, NR 1990, 'Charge dependence of Fe(II)-catalyzed DNA cleavage', Nucleic Acids Research, vol. 18, no. 11, pp. 3333-3337.
Lu M, Guo Q, Wink DJ, Kallenbach NR. Charge dependence of Fe(II)-catalyzed DNA cleavage. Nucleic Acids Research. 1990 Jun 11;18(11):3333-3337.
Lu, Min ; Guo, Qiu ; Wink, Donald J. ; Kallenbach, Neville R. / Charge dependence of Fe(II)-catalyzed DNA cleavage. In: Nucleic Acids Research. 1990 ; Vol. 18, No. 11. pp. 3333-3337.
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