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The nucleoside 2,2,4-triamino-5(2H)-oxazolone (Oz) can result from oxidative damage to guanine residues in DNA. Despite differences among the three polymerases (Pol β, KF exo−, and Pol η) regarding nucleotide incorporation patterns opposite Oz, all three polymerases can incorporate guanine opposite Oz. Based on ab initio calculations, we proposed a structure for a stable Oz:G base pair. Here, to assess the stability of each Oz-containing base pair (Oz:G, Oz:A, Oz:C, and Oz:T) upon DNA replication, we determined the efficiency of Pol β-, KF exo−-, or Pol η-catalyzed primer extension beyond each base pair. With each polymerase, extension beyond Oz:G was more efficient than that beyond Oz:A, Oz:C, or Oz:T. Moreover, thermal denaturation studies revealed that the T m value for the duplex containing Oz:G was significantly higher than those obtained for duplexes containing Oz:A, Oz:C, or Oz:T. Therefore, the results from ab initio calculations along with those from DNA replication assays and thermal denaturation experiments supported the conclusion that Oz:G is the most stable of the Oz-containing base pairs.

Carbyne is one of the allotropes of sp-carbon with a one-dimensional chain, but its physicochemical properties have not yet been clarified. We produced a carbyne-like carbon (carbon containing sp bond) electrode by electrochemical reduction in an organic electrolyte (1.0 mol dm−3 LiClO4/propylene carbonate) using a poly(tetrafluoroethylene) (PTFE) film electrode coated with a thin gold layer. The Li+ ion can be doped/undoped in the carbyne-like carbon film by electrochemical reduction/oxidation. The stoichiometry of the electrochemically reduced PTFE is estimated to be CLi0.48·2LiF which corresponds to a lithium ion battery negative electrode with ≈1100 mAh g−1 (of carbon) capacity.

8-Oxoguanine is the typical oxidative product, but 8-oxoguanine is further oxidized by several oxidizing agents. Here, we investigated the oxidation of 2'-deoxy-8-oxoguanosine with aqueous iodine.