title: Biophysical stability and enzymatic recognition of oxanine in DNA.
abstract: Oxanine (Oxa), which is one of the major products generated from guanine by nitrosative oxidation and is as long-lived as Gua in DNA, has been thought to be one of the major causes for NO-induced DNA damage. In the present study, using several synthetic Oxa-containing oligodeoxynucleotides, biophysical stability and enzymatic recognition of Oxa was investigated in DNA strands. It was found that Oxa did not mediate marked distortion in the whole DNA structure although Oxa pairing with 4 normal bases decreased thermal stability of the DNA duplexes compared to Gua:Cyt base pair. Regarding the responses of the DNA-relevant enzymes to Oxa, it was determined that Oxa was recognized as Gua except that DNA polymerases incorporated Thy as well as Cyt opposite Oxa. These results imply that Oxa tends to behave as a kind of naturally occurring base, Gua and therefore, would be involved in the genotoxic and cytotoxic threats of NO in cellular system.
authors: Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan.
authors: Seung Pil
authors: SP
authors: Pack
authors: Akihiro
authors: A
authors: Doi
authors: Mitsuru
authors: M
authors: Nonogawa
authors: Nagendra K
authors: NK
authors: Kamisetty
authors: Kamakshaiah C
authors: KC
authors: Devarayapalli
authors: Tsutomu
authors: T
authors: Kodaki
authors: Keisuke
authors: K
authors: Makino
mesh_terms: D020029:Base Pairing; D055592:Biophysical Phenomena; D001703:Biophysics; D004247:DNA / Q000737:chemistry*; D004249:DNA Damage; D004798:Enzymes / Q000737:chemistry; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D011684:Purine Nucleosides / Q000032:analysis*
chemical_list: D004798:Enzymes; D009838:Oligodeoxyribonucleotides; D011684:Purine Nucleosides; C468766:oxanine; D004247:DNA