Development of novel PRODAN-labeled nucleosides as base-discriminating fluorescent probes.

We have developed a PRODAN-labeled uridine ((PDN)U), which contains a polarity-sensitive chromophore at the C-5 position of uracil. This paper describes the synthesis and fluorescent properties of oligodeoxy-nucleotides (ODNs) containing PRODAN-labeled nucleosides ((PDN)C, (PDN)A, and (PDN)G). PRODAN chromophore was attached to cytosine at the C-5 position and to purine bases at the C-8 position to extend into the major groove. When BDF probes containing a PRODAN-labeled nucleoside hybridize with a "full-matched" ODN, the fluorescence spectrum showed a strong emission around 520 nm on 450 nm excitation. In contrast, when PRODAN-labeled nucleoside analogs form a "mismatched" base pair, the fluorescence was weaker.