Radiation damage to triplex DNA induced by γ-rays: a footprinting study and Monte Carlo simulation
| Autor: | M. Begusova, D. Sy, E. La Nave, Flavia Barone, Mirella Matzeu, Filomena Mazzei |
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| Rok vydání: | 2000 |
| Předmět: |
Models
Molecular DNA Footprinting In Vitro Techniques Radiation Tolerance chemistry.chemical_compound Radiation damage Radiology Nuclear Medicine and imaging Nucleotide Irradiation chemistry.chemical_classification Gel electrophoresis Base Sequence Radiological and Ultrasound Technology business.industry DNA Footprinting Electrophoresis Crystallography chemistry Gamma Rays Duplex (building) Nucleic Acid Conformation Nuclear medicine business Monte Carlo Method DNA Damage |
| Zdroj: | International Journal of Radiation Biology. 76:731-740 |
| ISSN: | 1362-3095 0955-3002 |
| Popis: | This study is aimed at comparing the radiosensitivity of a 21-mer DNA fragment in duplex and triplex form (Py x Pu duplex and Py x Pu:Py triplex) and to give insights into the fine structural features due to the different strandedness.The triplex sample was characterized by means of electrophoretic mobility, circular dichroism spectra and UV melting experiments. Triplex and duplex, labelled on the homopyrimidine or homopurine strand, were irradiated with 60Co gamma-rays. The samples were analysed by sequencing gel electrophoresis and the patterns of relative probabilities of frank strand breakage (FSB) and alkali-revealed breakage (ARB) at each nucleotide site were determined. Relative probabilities of OH* radical attack to duplex and triplex DNA built up with a molecular modelling software were calculated using a previously reported simulation procedure (Sy et al. 1997). The experimental data were compared with the results of the theoretical simulations of OH* radical attack to DNA.Globally, the duplex is more attacked than the triplex, mainly in the Pu strand. Sequence-dependent variations of FSB and FSB+ARB probabilities in both duplex and triplex were revealed. No significant differences between the patterns of damage in the triplex and in the duplex were observed.The presence of the third Py strand located in the major groove of the DNA duplex modifies the total yields of radiation-induced DNA damage, but not the sequence-dependent patterns of relative probability of damage at each nucleotide site. |
| Databáze: | OpenAIRE |
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