The synthesis of oligonucleotide-polyamide conjugate molecules suitable as PCR primers
作者:Glenn Tong、John M. Lawlor、Geoffrey W. Tregear、Jim Haralambidis
DOI:10.1021/jo00060a044
日期:1993.4
A new class of oligonucleotide-polyamide conjugates having free 3'-termini has been developed. These molecules have the potential to act as multiply-labeled nonradioactive polymerase chain reaction (PCR) primers. The linkage between the oligonucleotide and the polyamide is via a C5-modified deoxyuridine, synthesized in three steps from 5-iodo-2'-deoxyuridine (6). Subsequent palladium-catalyzed coupling of the 5'-O-protected deoxyuridine derivative 7 and the N-protected propargylamines 11 and 12 gave the alkynyl nucleosides 3 and 4, respectively. Both of these were then incorporated onto succinyl-CPG resin by diisopropylcarbodiimide/DMAP-mediated esterifications to give 18 and 19, respectively. Acidolytic removal of all protecting groups, selective acylation at the C5 pendant amine by an activated N(alpha)-(9-fluorenylmethoxycarbonyl) (Fmoc)-protected amino acid followed by reprotection of the 5'-hydroxyl by tritylation with 4,4'-dimethoxytrityl chloride gave the solid support 22. Standard Fmoc solid-phase peptide synthesis on the C5 pendant arm of 22 followed by oligonucleotide synthesis using standard phosphoramidite chemistry on the 5'-hydroxyl gave the desired oligonucleotide-polyamide conjugate 5. A single biotin label was incorporated into the polyamide using the biotinylated lysine synthon 29; this method is expected to be readily applicable for the attachment of multiple biotin residues in a facile and highly-controlled manner. The conjugate 5 was characterized by UV spectroscopy, amino acid analysis, 5'-end labeling with P-32 and reversed-phase C18 HPLC analysis of enzymatic digests. Preliminary experiments with 5 have shown that it is an efficient PCR primer.