title: The base pairing properties of 8-aza-7-deaza-2'-deoxyisoguanosine and 7-halogenated derivatives in oligonucleotide duplexes with parallel and antiparallel chain orientation.
abstract: The base pairing properties of oligonucleotide duplexes containing 8-aza-7-deaza-2'-deoxyisoguanosine, its 7-bromo or its 7-iodo derivative are described. The nucleosides were synthesized on a convergent route, protected and converted into phosphoramidites. Oligonucleotides were prepared on a solid-phase and were hybridized to yield duplexes with parallel (ps) or antiparallel (aps) chain orientation. The 8-aza-7-deaza-2'-deoxyisoguanosine-containing duplexes show almost identical base pairing stability as those containing 2'-deoxyisoguanosine, while the 7-substituted derivatives induce a significant duplex stabilization both in ps and aps DNA. Self-complementary duplexes with parallel chain orientation are exceptionally stable due to the presence of 5'-overhangs. The bulky halogen substituents were found to be well accommodated in the grooves both of aps and ps DNA.
authors.affiliation: Laboratorium für Organische und Bioorganische Chemie, Institut für Chemie, Universität Osnabrück, Barbarastr. 7, D-49069 Osnabrück, Germany. frank.seela@uni-osnabrueck.de
authors.forename: Frank
authors.initials: F
authors.lastname: Seela
authors.forename: Rita
authors.initials: R
authors.lastname: Kröschel
mesh_terms: D020029:Base Pairing; D004247:DNA / Q000138:chemical synthesis / Q000737:chemistry*; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry*; D006207:Half-Life; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis / Q000737:chemistry; D013816:Thermodynamics
chemical_list: C480033:8-aza-7-deaza-2'-deoxyisoguanosine; D009838:Oligodeoxyribonucleotides; D004247:DNA; D003849:Deoxyguanosine