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*H atom and *OH radical reactions with 5-methylcytosine.

Authors
  • Grand, A
  • Morell, C
  • Labet, V
  • Cadet, J
  • Eriksson, L A
Type
Published Article
Journal
The journal of physical chemistry. A
Publication Date
Sep 20, 2007
Volume
111
Issue
37
Pages
8968–8972
Identifiers
PMID: 17722896
Source
Medline
License
Unknown

Abstract

The reactions between either a hydrogen atom or a hydroxyl radical and 5-methylcytosine (5-MeCyt) are studied by using the hybrid kinetic energy meta-GGA functional MPW1B95. *H atom and *OH radical addition to positions C5 and C6 of 5-MeCyt, or *OH radical induced H-abstraction from the C5 methyl group, are explored. All systems are optimized in bulk solvent. The data presented show that the barriers to reaction are very low: ca. 7 kcal/mol for the *H atom additions and 1 kcal/mol for the reactions involving the *OH radical. Thermodynamically, the two C6 radical adducts and the *H-abstraction product are the most stable ones. The proton hyperfine coupling constants (HFCC), computed at the IEFPCM/MPW1B95/6-311++G(2d,2p) level, agree well with B3LYP results and available experimental and theoretical data on related thymine and cytosine radicals.

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