MDPI Acta Medica Okayama 1420-3049 29 10 2024 Recognition of 8-Oxo-2��-deoxyguanosine in DNA Using the Triphosphate of 2��-Deoxycytidine Connecting the 1,3-Diazaphenoxazine Unit, dCdapTP 2270 EN Takato Sakurada Graduate School of Pharmaceutical Sciences, Kyushu University Yuta Chikada Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Ryo Miyahara Graduate School of Pharmaceutical Sciences, Kyushu University Yosuke Taniguchi Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University DNA is constantly damaged by various external and internal factors. In particular, oxidative damage occurs in a steady state, and 8-oxo-2 '-deoxyguanosine (oxodG) is known as the main oxidative damage. OxodG is a strong genotoxic nucleoside and is thought to be involved in the pathogenesis of cancer and neurological diseases. However, a breakthrough method to detect the position of oxodG in DNA has not yet been developed. Therefore, we attempted to develop a novel method to detect oxodG in DNA using artificial nucleosides. Recently, we have succeeded in the recognition of oxodG in DNA by a single nucleotide elongation reaction using nucleoside derivatives based on a purine skeleton with a 1,3-diazaphenoxazine unit. In this study, we developed a new nucleoside derivative with a pyrimidine skeleton in order to further improve the recognition ability and enzymatic reaction efficiency. We, therefore, designed and synthesized 2 '-deoxycytidine-1,3-diazaphenoxazine (Cdap) and its triphosphate derivatives. The results showed that it was incorporated into the primer strand relative to the dG template because of its cytidine skeleton, but it was more effective at the complementary position of the oxodG template. These results indicate that the new nucleoside derivative can be considered as one of the new candidates for the detection of oxodG in DNA. No potential conflict of interest relevant to this article was reported.