title: Stabilization of tandem dG-dA base pairs in DNA-hairpins: replacement of the canonical bases by 7-deaza-7-propynylpurines.
abstract: The stabilizing effect of 7-propynylated 7-deazapurine nucleosides on DNA-hairpins and DNA-duplexes containing d(GA) mismatches was investigated. The corresponding oligonucleotides were synthesized using solid-phase synthesis. For this purpose, the phosphoramidite of 7-deaza-7-propynyl-2'-deoxyadenosine (3c) was prepared. The incorporation of 3c instead of dA into the tandem d(GA) base pair of a DNA-hairpin alters the secondary structure, but has a positive effect on the duplex stability. A complete replacement of the canonical nucleosides of the tandem d(GA) base pair by 3c and 7-deaza-7-propynyl-2'-deoxyguanosine results in a significant base pair stabilization.
authors.affiliation: Laboratorium für Organische und Bioorganische Chemie, Institut für Chemie, Universität Osnabrück, Barbarastrasse 7, 49069 Osnabrück, Germany. Frank.Seela@uni-osnabrueck.de
authors.forename: Frank
authors.initials: F
authors.lastname: Seela
authors.forename: Simone
authors.initials: S
authors.lastname: Budow
authors.forename: Khalil I
authors.initials: KI
authors.lastname: Shaikh
authors.forename: Anup M
authors.initials: AM
authors.lastname: Jawalekar
mesh_terms: D020029:Base Pairing; D001483:Base Sequence; D002942:Circular Dichroism; D003839:Deoxyadenosines / Q000737:chemistry*; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000737:chemistry; D009690:Nucleic Acid Conformation; D013816:Thermodynamics
chemical_list: C101165:7-(1-propynyl)-7-deaza-2'-deoxyadenosine; C101164:7-(1-propynyl)-7-deaza-2'-deoxyguanosine; D003839:Deoxyadenosines; D003849:Deoxyguanosine