Structural basis for DNA bending
- Yale Univ., New Haven, CT (USA)
The authors report proton NMR studies on DNA oligonucleotides that contain A tracts of lengths known to produce various degrees of bending. Spectra of duplexes in the series 5{prime}-(GGCA{sub n}CGG){center dot}(CCGT{sub n}GCC) (n = 3,4,5,7,9) reveal substantial structural changes within the A{sub n}{center dot}T{sub n} tract as its length is increased. Chemical-shift comparisons show that A tracts with fewer than about seven members do not contain regions of uniform structure. Throughout the series, there is a striking monotonic relationship between the location of an A{center dot}T pair in the A tract and the relative position of its ThyH3 resonance. The direction of this chemical-shift dispersion is opposite to that expected from consideration of ring-current effects alone. This model features a substantial negative base-pair tilt, which has been suggested previously as the source of A-tract bending. In contrast, the nuclear Overhauser effect distances are inconsistent with at least one known crystallographic A-tract structure which lacks appreciable base-pair tilt.
- OSTI ID:
- 5442395
- Journal Information:
- Proceedings of the National Academy of Sciences of the United States of America; (USA), Vol. 86:8; ISSN 0027-8424
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
DNA
NUCLEAR MAGNETIC RESONANCE
CHEMICAL SHIFT
CONFORMATIONAL CHANGES
CRYSTALLOGRAPHY
ION EXCHANGE CHROMATOGRAPHY
NMR SPECTRA
OLIGONUCLEOTIDES
OVERHAUSER EFFECT
PROTONS
STRUCTURAL MODELS
BARYONS
CHROMATOGRAPHY
ELEMENTARY PARTICLES
FERMIONS
HADRONS
MAGNETIC RESONANCE
NUCLEIC ACIDS
NUCLEONS
ORGANIC COMPOUNDS
RESONANCE
SEPARATION PROCESSES
SPECTRA
550601* - Medicine- Unsealed Radionuclides in Diagnostics