New developments in the synthesis of oligonucleotide-peptide conjugates

Abstract

Abstract. The stability of oligodeoxynucleotides to trifluoroacetic acid is studied.Pyrimidine oligonucleotides were stable in the conditions used for the removal of tbutyl groups.Oligonucleotide-3'-peptide conjugates carrying pyrimidine oligonucleotides are prepared stepwise using peptide-supports and Fmoc, t-butyl strategy. Using this strategy we have prepared an oligonucleotide-peptide conjugate containing as peptide the leucine-rich fragment of FOS, a transcription factor involved in many important cellular processes. This conjugate has a long peptide sequence with a large number of trifunctional amino acids.

Oligonucleotide-Peptide Conjugates: Solid-Phase Synthesis under Acidic Conditions and Use in ELISA Assays

“…In this way, the standard Fmo/ t -Bu strategy was used to synthesize the peptide; however, this method requires the use of TFA in the presence of the oligonucleotide, which may induce depurination. Although some authors have described the isolation of OPCs after TFA treatment [ 34 ], we found that purine 2′-deoxynucleotides are not stable to TFA [ 35 ]. For this reason the method may be restricted to polypyrimidine sequences [ 35 , 36 ].…”

“…Both protocols gave the desired conjugate as a major product but the yield was higher in the first. Nevertheless, this method allows the synthesis of only pyrimidine sequences, as these are stable to TFA [ 35 , 36 ].…”

Solid-Phase Synthesis of Oligonucleotide Conjugates Useful for Delivery and Targeting of Potential Nucleic Acid Therapeutics

“…After acidolytic detritylation, an oligothymidylate sequence has been assembled by phosphoramidite chemistry. Consecutive treatments with piperidine in DMF and 95% TFA have then given the conjugate (153). The question that remains to be answered is whether a heterosequence withstands without depurination the acidolytic removal of the tBu-derived side-chain protecting groups.…”

Total stepwise solid-phase synthesis of peptide–oligonucleotide conjugates using side-chain Boc/tBu protecting groups

“…Another promising approach is total stepwise solid-phase synthesis, in which the desired POC is assembled directly on a solid support and therefore requires only one-step purification. [17][18][19][20][21][22] Nevertheless, this seemingly simple method can be applied to only a limited number of amino acids, because removal of the sidechain protecting groups of the amino acids requires trifluoroacetic acid (TFA) treatment, which can induce depurination of the oligonucleotide (Scheme 1a). 7 In order to solve this problem, the side-chain functional groups of amino acids were temporarily protected using base-labile protecting groups.…”