ISSN:
1432-1017
Keywords:
Key wordsγ-Ray footprinting
;
Fluorescence polarization anisotropy
;
DNA damage
;
Oxidative lesion
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Physics
Notes:
Abstract The influence of the oxidative lesion 2′-deoxy-7-hydro-8-oxoguanosine (8-oxodG) on some conformational properties of DNA has been studied. Four 30-mer duplexes of the form [5′-GATCCTCTAGAGTC[G* or G]ACCTGCAGGCATGCA-3′]:[3′-CTAGGAGATCTCAG[C or A]TGGACGTCCGTACGT-5′], in which G* is the 8-oxodG lesion, were synthesized in order to compare the effect of the GA mismatch and of the damaged G*C and G*A forms with the normal GC. Spectroscopic measurements performed by means of UV denaturation and circular dichroism experiments do not show gross changes of stability and overall structure in the damaged and mismatched samples. The control DNA and the samples containing GA mismatch show very similar γ-rays cutting patterns, indicating that the introduction of the GA mismatch does not perturb the phosphate backbone geometry. In the samples containing the 8-oxodG there are some variations of the cleavage pattern near G* which are extended for almost one helical turn. Some differences are observed between G*C and G*A duplexes. In particular, in the G*C sample the reduced accessibility to OH radicals at the G15 site, observed in the control, spreads on the intrastrand adjacent bases and in the G*A sample a shift of the minimum is observed. The hydrodynamic radius R h derived by fluorescence polarization anisotropy decay exhibits a constant value of 11.4 ± 0.2 Å between 5 and 40 °C, in all the samples. The torsional constant α of each oligomer decreases when the temperature is raised and the α values of the damaged samples are higher than those of the normal ones.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002490050002
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