Degradation of DNA by iron-bleomycin: mechanistic implications of product /sup 18/O incorporation

Conference · Fri May 01 04:00:00 EDT 1987 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:6172687

Rabow, L E; McGall, G H; Stubbe, J; Kozarich, J W

Interaction of d(CGCGCG) with Bleomycin (BLM), activated either with Fe(III) and H/sub 2/O/sub 2/ or Fe(II), O/sub 2/ and one electron, results in production of cytosine and a modified oligonucleotide strand (1). Reduction of 1 with NaBD/sub 4/ followed by enzymatic digestion, derivatization, and GC-MS permits the identification of 2-deoxypentitols-1,4-d/sub 2/ as their tetra-trimethylsilyl (TMS) derivatives. Similar products have also been isolated from calf thymus DNA and poly(dG-dC). These results provide unequivocal evidence for the intermediacy of a 4' ketone, 1' aldehyde modified carbohydrate. An alternate mode of DNA degradation requires additional O/sub 2/ and leads to formation of 3' phosphoglycolate termini and base propenals. Glycolate (GA), released from calf thymus DNA, poly(dA-dT) or d(CGCGCG) by enzymatic digestion, can be isolated by chromatography on DEAE Sephadex, silylated and analyzed by GC-MS. This analysis, after incubation with Fe(II) x /sup 18/O/sub 2/ x BLM or Fe(III) x H/sub 2/ /sup 16/O/sub 2/ x BLM plus /sup 18/O/sub 2/, reveals the incorporation of a single atom of /sup 18/O at the C-1 position. Pulse-chase experiments demonstrate that it is the excess molecular oxygen and not the O/sub 2/ required for drug activation that is incorporated into the carboxylate group of 3' phosphoglycolate and provide evidence for the proposed addition of O/sub 2/ to a C4' carbon radical. Isotopic enrichments of the other products of DNA oxidation, formed in the presence of /sup 18/O/sub 2/ are also being determined.

• Research Organization: Univ. of Wisconsin, Madison
• OSTI ID: 6172687
• Report Number(s): CONF-870644-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 46:6
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANTI-INFECTIVE AGENTS
ANTIBIOTICS
ANTIMITOTIC DRUGS
ANTINEOPLASTIC DRUGS
BIOCHEMICAL REACTION KINETICS
BLEOMYCIN
CHROMATOGRAPHY
DNA
DRUGS
ELEMENTS
EVEN-EVEN NUCLEI
GAS CHROMATOGRAPHY
HYDROGEN COMPOUNDS
HYDROGEN PEROXIDE
IRON
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIGHT NUCLEI
MASS SPECTROSCOPY
METABOLISM
METALS
NUCLEI
NUCLEIC ACIDS
NUCLEOTIDES
ORGANIC COMPOUNDS
OXYGEN 16
OXYGEN 18
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
PEROXIDES
REACTION KINETICS
SEPARATION PROCESSES
SPECTROSCOPY
STABLE ISOTOPES
TRACER TECHNIQUES
TRANSITION ELEMENTS