Guanine modification during chemical DNA synthesis.
Base modification during solid-phase phosphoramidite synthesis of oligodeoxynucleotides has been investigated. We have discovered chemical modification that converts dG and dG-containing oligomers to a fluorescent form. This modification has been linked to N,N-dimethylaminopyridine (DMAP), an acylation catalyst, which can displace phosphate triester adducts at the 6-position of guanine. Further, we have found that this fluorescent intermediate can be converted in ammonium hydroxide solution to 2,6 diaminopurine deoxyribonucleoside (2,6 DAP), a potentially mutagenic nucleoside analog. We have shown that N-methylimidazole (NMI) in place of DMAP eliminates the fluorescent species and reduces 2,6 DAP contamination.
Eadie
J S
JS
Applied Biosystems, Inc., Foster City, CA 94404.
Davidson
D S
DS
D002851:Chromatography, High Pressure Liquid; D004247:DNA / Q000138:chemical synthesis*; D003849:Deoxyguanosine / Q000031:analogs & derivatives*; D007202:Indicators and Reagents; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis* / Q000302:isolation & purification
D007202:Indicators and Reagents; D009838:Oligodeoxyribonucleotides; D004247:DNA; D003849:Deoxyguanosine