Nucleic Acids Research, 2003, Vol. 31, No. 24 7175-7188
© 2003 Oxford University Press
Article |
A new, but old, nucleoside analog: the first synthesis of 1-deaza-2'-deoxyguanosine and its properties as a nucleoside and as oligodeoxynucleotides
Institute for Biological Resources and Functions and 1 Fellow Research Group, National Institute of Advanced Industrial Science and Technology (AIST, Hokkaido), 2-17-2-1 Tsukisamu-Higashi, Toyohira-ku, Sapporo 062-8517, Japan and 2 Gene Function Research Laboratory, National Institute of Advanced Industrial Science and Technology (AIST, Central 4), 1-1-1 Higashi, Tsukuba Science City, Ibaraki 305-8562, Japan
*To whom correspondence should be addressed. Tel: +81 11 857 8957; Fax: +81 11 857 8448; Email: naoshi-kojima{at}aist.go.jp
The first synthesis of 5-amino-3-(2'-deoxy-ß-D-ribofuranosyl)imidazo[4,5-b]pyridin-7-one (1-deaza-2'-deoxyguanosine) is described. The compound was converted from the known AICA-deoxyriboside. The tautomeric structure of the base moiety was determined by theoretical calculation to be a hydroxyl form. Although the analog was found to be labile to acidic conditions, 1-deaza-2'-deoxyguanosine was successfully converted into a phosphoramidite derivative, which was incorporated into oligodeoxynucleotides by the standard phosphoramidite method. Thermal stabilities of oligodeoxynucleotides containing 1-deaza-2'-deoxyguanosine were investigated by thermal denaturing experiments. Also, a triphosphate analog of 1-deaza-2'-deoxyguanosine was synthesized for polymerase extension reactions. Single nucleotide insertion reactions using a template containing 1-deaza-2'-deoxyguanosine, as well as 1-deaza-2'-deoxyguanosine triphosphate, were performed using the Klenow fragment (exonuclease minus) polymerase and other polymerases. No hydrogen bonded base pairs, even a 1-deaza-2'-deoxyguanosine:cytidine base pair, were indicated by thermal denaturing studies. However, though less selective and less effective than the natural guanosine counterpart, the polymerase extension reactions suggested the formation of a base pair of 1-deaza-2'-deoxyguanosine with cytidine during the insertion reactions.