Fluorescence detection of 8-oxoguanosine by G-clamp derivatives.

8-Oxoguanosine, which is derived by the oxidation of guanosine (dG), is known to induce transversion mutations (G:C-->T:A) in DNA. The compounds with small molecular weight for recognizing 8-oxoG were designed on the basis of the structure of the G-clamp, which is reported to have selective affinity toward guanosine. The G-clamp derivatives with the additional binding units toward 8-oxoG were effectively synthesized and named "8-oxoG-clamps". Binding properties were measured by fluorescence quenching of 8-oxoG-clamps. Among the synthesized derivatives, 8-oxoG-clamp with N-benzyloxycarbonyl (Cbz) unit completely discriminated 8-oxoG from other nucleosides by fluorescence quenching.