Conformation of 2-aminofluorene-modified DNA

Journal Article · Sat Jan 01 04:00:00 EST 1983 · Biopolymers; (United States)

DOI:https://doi.org/10.1002/bip.360221109· OSTI ID:5942950

Broyde, S; Hingerty, B

Minimized potential-energy calculations were performed to determine the conformation of the 2-aminofluorene (AF) adduct to dCpdG at guanine C-8. The AF adduct has many low-energy conformers in both the anti and the syn domains of the guanine. This is in contrast with the acetylated adduct, (AAF), which greatly prefers the syn domain. Two types of low-energy guanine anti-conformations were obtained: (1) conformers that preserve guanine-cytidine stacking and (2) conformers with fluorene-cytidine stacking. Of special importance are conformers with omega,omega,phi = g/sup -/,g/sup -/,g/sup +/, characteristic of normal A- or B-helices, which are found in both groups. No conformers of this type were obtained for the acetylated AAF adduct. The guanine-cytidine stacked form with this conformation can be incorporated in the B-helix without any distortion, with the carcinogen situated at the helix exterior. The fluorene in this model can slide into the helix to yield a fluorene-cytidine stacked minimum-energy conformation. This requires no denaturation, although one base pair is unstacked and the helix axis is bent. Low-energy syn-conformations, similar to those obtained for the AAF adduct, were also computed. These were either guanine-cytidine stacked or fluorene-cytidine stacked. The syn forms are less likely to be observed in larger DNA polymers of the AF adduct, since they cause more distortion than the anti-conformations. However, they might well be observed in crystals of small subunits, and they should contribute significantly to the population in solution. 56 references, 10 figures, 5 tables.

• Research Organization: New York Univ., NY
• DOE Contract Number: AC02-81ER60015
• OSTI ID: 5942950
• Journal Information: Biopolymers; (United States), Journal Name: Biopolymers; (United States) Vol. 22; ISSN BIPMA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
ADDUCTS
AMINES
AROMATICS
AZAARENES
AZINES
CARCINOGENS
CONDENSED AROMATICS
CONFIGURATION
CYTIDINE
DATA
DNA
DNA ADDUCTS
ENERGY
EXPERIMENTAL DATA
FLUORENE
GUANINE
HELICAL CONFIGURATION
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
HYDROXY COMPOUNDS
INFORMATION
MATHEMATICAL MODELS
MOLECULAR MODELS
MOLECULAR STRUCTURE
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
POTENTIAL ENERGY
PURINES
PYRIMIDINES
RIBOSIDES