Plasmid DNA damage induced by singlet molecular oxygen released from the naphthalene endoperoxide DHPNO2 and photoactivated methylene blue

To investigate oxidative lesions and strand breaks induction by singlet molecular oxygen (¹O2), supercoiled-DNA plasmid was treated with thermo-dissociated DHPNO2 and photoactivated-methylene blue. DNA lesions were detected by Fpg that cleaves DNA at certain oxidized bases, and T4-endoV, which cleav...

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Published inQuímica nova Vol. 33; no. 2; pp. 279 - 283
Main Authors Berra, Carolina Maria, Menck, Carlos Frederico Martins, Martinez, Glaucia Regina, Oliveira, Carla Santos de, Baptista, Maurício da Silva, Di Mascio, Paolo
Format Journal Article
LanguageEnglish
Published Sociedade Brasileira de Química 2010
Subjects
DNA lesions
oxidative stress
singlet molecular oxygen
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Summary:To investigate oxidative lesions and strand breaks induction by singlet molecular oxygen (¹O2), supercoiled-DNA plasmid was treated with thermo-dissociated DHPNO2 and photoactivated-methylene blue. DNA lesions were detected by Fpg that cleaves DNA at certain oxidized bases, and T4-endoV, which cleaves DNA at cyclobutane pyrimidine dimers and apurinic/apyrimidinic (AP) sites. These cleavages form open relaxed-DNA structures, which are discriminated from supercoiled-DNA. DHPNO2 or photoactivated-MB treatments result in similar plasmid damage profile: low number of single-strand breaks or AP-sites and high frequency of Fpg-sensitive sites; confirming that base oxidation is the main product for both reactions and that ¹O2 might be the most likely intermediate that reacts with DNA.
ISSN:0100-4042
1678-7064
DOI:10.1590/S0100-40422010000200009