title: 2'-Deoxyimmunosine: stereoselective synthesis, base pairing and duplex stability of oligonucleotides containing 8-oxo-7-thiaguanine.
abstract: Oligonucleotides containing 7-thia-8-oxoguanine represent a new class of molecules in which sulfur replaces the 7-nitrogen of a purine base. The monomeric 7-thia-8-oxoguanine 2'-deoxyribonucleoside (2'-deoxyimmunosine, 4) was prepared by nucleobase anion glycosylation in a regio- and stereoselective way employing 5-{[(di-n-butylamino)methylidene]amino}thiazolo[4,5-d]pyrimidine-2,7(3H,6H)-dione (18) and 1-chloro-2-deoxy-3,5-di-O-p-toluoyl-alpha-d-erythro-pentofuranose (6). The nucleoside was converted into the phosphoramidite and oligonucleotides were prepared by solid-phase synthesis. Oligonucleotide duplexes containing the 4-dC base pair show a similar stability as those containing the dG-dC motif. Thus the sterically demanding sulfur and the additional 8-oxo group are well accommodated in the major groove of DNA. As expected, compound 4 does not form a Hoogsteen pair, as reported for 8-oxo-2'-deoxyguanosine. Compared to 2'-deoxyguanosine, 2'-deoxyimmunosine shows a better mismatch discrimination in Watson-Crick base pairs.
authors.affiliation: Laboratory of Bioorganic Chemistry and Chemical Biology, Center for Nanotechnology, Heisenbergstrasse 11, 48149, Münster, Germany. Frank.Seela@uni-osnabrueck.de
authors.forename: Frank
authors.initials: F
authors.lastname: Seela
authors.forename: Xin
authors.initials: X
authors.lastname: Ming
mesh_terms: D020029:Base Pairing; D018360:Crystallography, X-Ray; D006151:Guanosine / Q000031:analogs & derivatives* / Q000737:chemistry; D006860:Hydrogen Bonding; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000138:chemical synthesis* / Q000737:chemistry*; D011741:Pyrimidine Nucleosides / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: C524201:5-amino-3-(2-deoxypentofuranosyl)thiazolo(4,5-d)pyrimidine-2,7-3H,6H-dione; D009841:Oligonucleotides; D011741:Pyrimidine Nucleosides; D006151:Guanosine