title: Oligonucleotide duplexes containing N8-glycosylated 8-aza-7-deazaguanine and self-assembly of 8-aza-7-deazapurines on the nucleoside and the oligomeric level.
abstract: The 8-aza-7-deazaguanine N8-(2'-deoxy-beta-D-ribofuranoside) (1) was synthesized, converted into the phosphoramidite 4 and incorporated into oligonucleotides. Nucleoside 1 forms stable base pairs with 2'-deoxy-5-methylisocytidine in DNA with antiparallel chain orientation (aps) and with 2'-deoxycytidine in duplexes with parallel chains (ps). According to the CD spectra self-complementary oligonucleotides d(1-m5isoC)3 and d(1-C), form autonomous DNA-structures. Neither the nucleoside 1 nor the regularly linked 8-aza-7-deaza-2'-deoxyguanosine form G-like tetrads while the regularly linked 8-aza-7-deaza-2'-deoxyisoguanosine gives higher molecular assemblies which are destroyed by bulky 7-bromo substituents. This was verified on monomeric nucleosides by ESI-MS spectrometry and on oligonucleotides by HPLC analysis.
authors.affiliation: Laboratorium für Organische und Bioorganische Chemie, Institut für Chemie, Fachbereich Biologie/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: D020816:Amino Acid Motifs; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D002942:Circular Dichroism; D003562:Cytidine / Q000737:chemistry; D004247:DNA / Q000737:chemistry; D006031:Glycosylation; D007477:Ions; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008956:Models, Chemical; D009711:Nucleotides / Q000737:chemistry; D009841:Oligonucleotides / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013696:Temperature; D013997:Time Factors
chemical_list: D007477:Ions; D009711:Nucleotides; D009841:Oligonucleotides; C083576:isocytidine; D003562:Cytidine; D004247:DNA