Light-induced nicking of deoxyribonucleic acid by cobalt(III) bleomycins

C. H. Chang, C. F. Meares

Research output: Contribution to journalArticle

90 Citations (Scopus)

Abstract

The anticancer drug bleomycin is a glycopeptide that causes strand scission of DNA both in vivo and in vitro. Cleavage of DNA by bleomycin has been studied extensively in vitro, with the findings that ferrous ion and molecular oxygen must be present and that addition of reducing agents greatly enhances the reaction. To date, only iron has been shown to be an effective metal cofactor for the cleavage of DNA by bleomycin. Here it is reported that two stable cobalt(III) complexes of bleomycin are strikingly effective in causing single-strand breaks (nicks) in supercoiled DNA in the presence of ultraviolet or visible radiation. For example, 366-nm light from an 18-W long-wavelength mercury lamp for 1 h causes 10-6 M cobalt(III) bleomycin to completely convert supercoiled φX174 DNA (10-8 M DNA, 10-4 M phosphate) into the nicked circular form. Furthermore, numerous alkali-labile sites are produced on the DNA during this treatment. The observed reactions are not caused by adventitious iron, and they occur only in the presence of cobalt(III) bleomycin and light.

Original languageEnglish (US)
Pages (from-to)6332-6334
Number of pages3
JournalBiochemistry
Volume21
Issue number25
StatePublished - 1982

Fingerprint

Bleomycin
Cobalt
Superhelical DNA
Light
DNA Cleavage
DNA
Iron
Glycopeptides
Reducing Agents
Alkalies
Mercury
Mercury vapor lamps
Molecular oxygen
Metals
Phosphates
Ions
Oxygen
cobalt bleomycin
Pharmaceutical Preparations
Radiation

ASJC Scopus subject areas

  • Biochemistry

Cite this

Chang, C. H., & Meares, C. F. (1982). Light-induced nicking of deoxyribonucleic acid by cobalt(III) bleomycins. Biochemistry, 21(25), 6332-6334.

Light-induced nicking of deoxyribonucleic acid by cobalt(III) bleomycins. / Chang, C. H.; Meares, C. F.

In: Biochemistry, Vol. 21, No. 25, 1982, p. 6332-6334.

Research output: Contribution to journalArticle

Chang, CH & Meares, CF 1982, 'Light-induced nicking of deoxyribonucleic acid by cobalt(III) bleomycins', Biochemistry, vol. 21, no. 25, pp. 6332-6334.
Chang, C. H. ; Meares, C. F. / Light-induced nicking of deoxyribonucleic acid by cobalt(III) bleomycins. In: Biochemistry. 1982 ; Vol. 21, No. 25. pp. 6332-6334.
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