Synthesis of N-methyl-N-nitrosourea linked to a methidium chloride analogue and its reactions with /sup 32/P-end-labeled DNA
The synthesis and characterization of an N-methyl-N-nitrosourea (MNU) analogue that is covalently linked to methidium nucleus (9) is described. At 37/degrees/C in pH 8.0 buffer 9 hydrolyzes via pseudo-first-order kinetics, with a calculated t/sub 1/2/ = 77 min. By use of polyacrylamide sequencing gels the formation of piperidine-labile N/sup 7/-methylguanine adducts from the reaction of 9 and MNU with 5'-/sup 32/P-end-labeled DNA restriction fragments is reported. DNA methylation by 9 in 10 mM Tris buffer is enhanced with increasing ionic strength (50-200 mM NaCl), which contrasts to the inhibition of MNU-induced cleavage with increasing salt. In addition, 9 methylates all G sites equally, while MNU shows a clear preference for d(G)/sub n/ (n greater than or equal to 3) runs and an asymmetrical methylation pattern within these G-rich regions. The results are discussed in terms of the delivery of the MNU moiety to the DNA target by a non-sequence-specific intercalation process and the subsequent hydrolytic generation of a nondiffusible alkylating intermediate.
- Research Organization:
- Univ. of Nebraska Medical Center, Omaha (USA)
- OSTI ID:
- 6208654
- Journal Information:
- Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 27:23; ISSN BICHA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Studies on in vitro S-methylation of naturally occurring thiol compounds with N-methyl-N-nitrosourea and methyl methanesulfonate
DNA base changes and alkylation following in vivo exposure of Escherichia coli to N-methyl-N-nitrosourea or N-ethyl-N-nitrosourea
Related Subjects
560300 -- Chemicals Metabolism & Toxicology
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BIOSYNTHESIS
DAYS LIVING RADIOISOTOPES
DNA
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
MAGNETIC RESONANCE
NITROSO COMPOUNDS
NITROSOUREAS
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUCLEIC ACIDS
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
RADIOISOTOPES
RESONANCE
STRAND BREAKS
SYNTHESIS