Oxidative lesions are the most widespread form of damage in living organisms. Oxidative events are mostly caused by the action of reactive oxygen species (ROS) onto DNA. Hydroxyl radicals (HOo) are very reactive toward DNA at various positions of the bases and the sugar moieties. It has been estimated that around 104 bases are oxidized per day in each human cell.1 In particular, 5'R and 5'S diastereoisomers of both 5',8-Cyclo-2'-deoxyguanosine (cdGuo) and 5',8-Cyclo-2'-deoxyadenosine (cdAdo) have been shown to be generated upon exposure to ionizing radiations, both in model DNA polymers and in cellular DNA.2 In order to get more insights into the efficiency of repair enzymes in cell cultures, the phosphoramidite synthons of (5'R)- and (5'S)-5',8-cyclopurines were synthesized and inserted into four appropriate oligonucleotide sequences by automated procedures. The modified DNA oligomers were analyzed by both ESI-MS and enzymatic digestion with exo and endonucleases. The four oligonucleotides containing each of the four cyclopurine lesions were also incorporated into 135-mer DNA duplexes, thus allowing the relative NER efficiency to be investigated in whole cell extracts. 1. L.H. Thompson, D. Schild, Mutat. Res. Fundam. Mol. Mech. Mutag. 2001, 477, 131-153. 2. N. Belmadoui, F. Boussicault, M. Guerra, J.L. Ravanat, C. Chatgilialoglu, J. Cadet Org. Biomol. Chem. 2010, 8, 3211-3219.
Synthesis and characterization of oligonucleotides as models of DNA containing biomarkers of free radical damage
Annalisa Masi;Chryssostomos Chatgilialoglu
2012
Abstract
Oxidative lesions are the most widespread form of damage in living organisms. Oxidative events are mostly caused by the action of reactive oxygen species (ROS) onto DNA. Hydroxyl radicals (HOo) are very reactive toward DNA at various positions of the bases and the sugar moieties. It has been estimated that around 104 bases are oxidized per day in each human cell.1 In particular, 5'R and 5'S diastereoisomers of both 5',8-Cyclo-2'-deoxyguanosine (cdGuo) and 5',8-Cyclo-2'-deoxyadenosine (cdAdo) have been shown to be generated upon exposure to ionizing radiations, both in model DNA polymers and in cellular DNA.2 In order to get more insights into the efficiency of repair enzymes in cell cultures, the phosphoramidite synthons of (5'R)- and (5'S)-5',8-cyclopurines were synthesized and inserted into four appropriate oligonucleotide sequences by automated procedures. The modified DNA oligomers were analyzed by both ESI-MS and enzymatic digestion with exo and endonucleases. The four oligonucleotides containing each of the four cyclopurine lesions were also incorporated into 135-mer DNA duplexes, thus allowing the relative NER efficiency to be investigated in whole cell extracts. 1. L.H. Thompson, D. Schild, Mutat. Res. Fundam. Mol. Mech. Mutag. 2001, 477, 131-153. 2. N. Belmadoui, F. Boussicault, M. Guerra, J.L. Ravanat, C. Chatgilialoglu, J. Cadet Org. Biomol. Chem. 2010, 8, 3211-3219.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.