Structure and relative stability of deoxyribose radicals in a model DNA backbone. Ab initio molecular orbital calculations

Journal Article · Thu Mar 16 04:00:00 EST 1995 · Journal of Physical Chemistry

DOI:https://doi.org/10.1021/j100011a064· OSTI ID:35465

Colson, A O; Sevilla, M D ^[1]

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1. Oakland Univ., Rochester, MI (United States)

Ab initio molecular orbital calculations have been performed in this study to determine the stability of five deoxyribose centered radicals embedded in a short DNA segment. The effect of phosphate groups on the sugar radical conformation, energetics, and electronic properties are evaluated through a comparison of models with and without phosphate groups. Geometry optimization performed at the ROHF/3-21G level reveals the C1` centered radical is the most energetically favored in all the DNA fragments considered in this study, while the C2` radical is the least stable and maintains a near planar configuration ({sup 4}{sub 0}T). All energy minima calculated correspond to deoxyribose radicals with a pseudorotation phase angle lying in the S quadrant of the pseudorotation cycle. The phosphate groups significantly affect the puckering mode of the C2` and C3` radicals and energetically destabilize C3` radical relative to the other sugar radicals. Isotropic hyperfine coupling constants significantly differ between models with and without phosphate groups, most particularly in the C3` and C4` radicals. Cytosine attachment to the C1` and C4` deoxyribose radicals does not appear to affect the relative energies nor the isotropic hyperfine couplings of these two species. 42 refs., 9 figs., 4 tabs.

• Sponsoring Organization: USDOE
• DOE Contract Number: FG02-86ER60455
• OSTI ID: 35465
• Journal Information: Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 11 Vol. 99; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
55 BIOLOGY AND MEDICINE
BASIC STUDIES
99 GENERAL AND MISCELLANEOUS
BOND ANGLE
BOND LENGTHS
CHEMICAL BONDS
COMPUTER CALCULATIONS
DEOXYRIBOSE
DNA
ELECTRONIC STRUCTURE
GEOMETRY
MOLECULAR ORBITAL METHOD
NUMERICAL DATA
RADICALS
STABILITY
THEORETICAL DATA