Torsional constant of 27-mer DNA oligomers of different sequences
| Autor: | Francesco Pedone, Mirella Matzeu, Flavia Barone, Filomena Mazzei |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Circular dichroism
Base Sequence Chemistry Circular Dichroism Organic Chemistry Enthalpy Molecular Sequence Data Biophysics Stacking Crystal structure DNA Biochemistry chemistry.chemical_compound Crystallography Biopolymers Fluorescence Polarization Immunoassay Nucleic Acid Conformation Torsion constant Fluorescence anisotropy Torsional rigidity |
| Popis: | We have studied the torsional elastic constant (alpha) of short DNA (27mer) oligomers of various sequence by fluorescence polarization anysotropy (FPA) measurements. The lowest alpha values were found in samples with sequence rich in AA dinucleotides or containing the alternating d(A-T) x d(A-T) motif. The torsional rigidity of our DNA samples was compared to that calculated according to the current values of twist angle fluctuations derived for ten dinucleotide steps by recent analyses of DNA crystal structure database. The values of torsional rigidity derived from crystals are higher than our experimental ones, obtained by FPA analysis, suggesting that packing force in crystals may notably hinder the dinucleotide twist angle fluctuations that occur in solution. This behaviour is more evident for samples containing AA, TA and AT steps. In all the samples there is about a twofold change of the alpha value in the 10-40 degrees C range. An activation enthalpy (Delta H (#)) of about 17.4 kJ mol(-1), on average, was obtained for the temperature dependence of eight of the ten samples studied. A correlation with the stacking energy is discussed. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|