Scientific Publications by FDA Staff

Bioconjug Chem 2008 Aug;19(8):1696-706

Thermolytic release of covalently linked DNA oligonucleotides and their conjugates from controlled-pore glass at near neutral pH.

Grajkowski A, Cieslak J, Kauffman JS, Duff RJ, Norris S, Freedberg DI, Beaucage SL

Beaucage, SL, US FDA, Div Therapeut Prot, Ctr Drug Evaluat & Res, 8800 Rockville Pike, Bethesda, MD 20892 USA US FDA, Div Therapeut Prot, Ctr Drug Evaluat & Res, Bethesda, MD 20892 USA US FDA, Div Bacterial Parasit & Allergen Prod, Ctr Biol Evaluat & Res, Bethesda, MD 20892 USA Lancaster Labs, Lancaster, PA 19605 USA

The functionalization of long chain alkylamine controlled-pore glass (CPG) with a 3-hydroxypropyl-(2-cyanoethyl)thiophosphoryl linker and its conversion to the support 7 has led to the synthesis of DNA oligonucleotides and their 3'- or (3',5')-conjugates. Indeed, CPG support 7 has been successfully employed in the synthesis of both native and fully phosphorothioated DNA 20-mers. Unlike conventional succinylated CPG supports, this distinctively functionalized support allows oligonucleotide deprotection and removal of the deprotection side products to proceed without releasing the oligonucleotide into the aqueous milieu. When freed from deprotection side products, the DNA oligonucleotide is thermolytically released from the support within 2 h under nearly neutral conditions (pH 7.2, 90 degrees C). The quality of these oligonucleotides is comparable to that of identical oligonucleotides synthesized from succinylated CPG supports in terms of shorter than full length oligonucleotide contaminants and overall yields. The versatility of the thermolytic CPG support 7 is further demonstrated by the synthesis of a DNA oligonucleotide (20-mer) and its conjugation with an azido and alkynyl groups at both 5'-and 3'-termini, respectively. The functionality of the (3',5')-heteroconjugated oligonucleotide 18 is verified by its circularization to the DNA oligonucleotide 19 under "click" chemistry conditions.