Base-pairing preferences, physicochemical properties and mutational behaviour of the DNA lesion 8-nitroguanine.
|
| Abstract |
8-Nitro-2'-deoxyguanosine (8-nitrodG) is a relatively unstable, mutagenic lesion of DNA that is increasingly believed to be associated with tissue inflammation. Due to the lability of the glycosidic bond, 8-nitrodG cannot be incorporated into oligodeoxynucleotides (ODNs) by chemical DNA synthesis and thus very little is known about its physicochemical properties and base-pairing preferences. Here we describe the synthesis of 8-nitro-2'-O-methylguanosine, a ribonucleoside analogue of this lesion, which is sufficiently stable to be incorporated into ODNs. Physicochemical studies demonstrated that 8-nitro-2'-O-methylguanosine adopts a syn conformation about the glycosidic bond; thermal melting studies and molecular modelling suggest a relatively stable syn-8-nitroG·anti-G base pair. Interestingly, when this lesion analogue was placed in a primer-template system, extension of the primer by either avian myeloblastosis virus reverse transcriptase (AMV-RT) or human DNA polymerase β (pol β), was significantly impaired, but where incorporation opposite 8-nitroguanine did occur, pol β showed a 2:1 preference to insert dA over dC, while AMV-RT incorporated predominantly dC. The fact that no 8-nitroG·G base pairing is seen in the primer extension products suggests that the polymerases may discriminate against this pairing system on the basis of its poor geometric match to a Watson-Crick pair.
|
|---|---|
| Authors | Inder Bhamra, Patricia Compagnone-Post, Ian A O'Neil, Lesley A Iwanejko, Andrew D Bates, Richard Cosstick |
| Journal | Nucleic acids research (Nucleic Acids Res) Vol. 40 Issue 21 Pg. 11126-38 (Nov 2012) ISSN: 1362-4962 [Electronic] England |
| PMID | 22965127 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't) |
| Chemical References |
|
| Topics |
|
Join CureHunter, for free Research Interface BASIC access!
Realize the full power of the drug-disease research graph!