Synthesis and hybridization of dodecadeoxyribonucleotides containing a fluorescent pyridopyrimidine deoxynucleoside

Partially self-complementary dodecadeoxyribonucleotides containing a fluorescent nucleoside, 3-beta-D-2'-deoxyribofuranosyl-2, 7-dioxopyrido[2, 3-d]pyrimidine (pyridopyrimidine deoxynucleoside, dF) were synthesized by the phosphotriester solidphase method. A dodecanucleotide d(GGGAAFGTTCCC) pairing the analog and guanine at the centre of the chain showed a higher melting temperature than the corresponding G-C paired duplex. A similar comparison between A-T and A-F suggested that weaker hydrogen bonds exist when adenine and pyridopyrimidine residues are paired.