Oligonucleotide conjugation to a cell-penetrating (TAT) peptide by Diels-Alder cycloaddition.
Modifed oligonucleotides are routinely employed as analytical probes for use in diagnostics, e.g. in the examination of specific RNA sequences for infectious diseases, however, a major limiting factor in oligonucleotide-based diagnostics is poor cellular uptake of naked oligonucleotides. This problem can be overcome by covalent attachment of a so-called 'cell-penetrating peptide' to form an oligonucleotide peptide conjugate. Stepwise solid phase synthesis of such a conjugate is difficult and expensive due to the conflicting chemistries of oligonucleotides and peptides. A simple approach to overcome this is post-synthetic conjugation. Diels-Alder cycloaddition is an attractive methodology for oligonucleotide peptide conjugation; the reaction is fast, chemoselective and the reaction rate is greatly enhanced in aqueous media - ideal conditions for biological moieties. An oligodeoxyribonucleotide sequence has been derivatised with a series of dienes at the 5'-terminus, using a series of unique dienyl-modified phosphoramidites, and investigation into the effect of diene type on the efficiency of conjugation, using Diels-Alder cycloaddition with a maleimido-derivatised cell-penetrating (TAT) peptide, has been performed. This led to the observation that the optimal diene for conjugation was cyclohexadiene, allowing conjugation of oligodeoxyribonucleotides to a cell-penetrating peptide by Diels-Alder cycloaddition for the first time.
Steven
Victoria
V
Centre for Molecular Nanometrology, WestCHEM, Department of Pure and Applied Chemistry, 295 Cathedral Street, Glasgow, Scotland G1 1XL, UK.
Graham
Duncan
D
D000596:Amino Acids; D001483:Base Sequence; D002477:Cells / Q000378:metabolism; D008301:Maleimides / Q000737:chemistry; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry* / Q000378:metabolism*; D010539:Permeability; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000737:chemistry* / Q000378:metabolism*
D000596:Amino Acids; D008301:Maleimides; D009838:Oligodeoxyribonucleotides; D010446:Peptide Fragments; D054322:tat Gene Products, Human Immunodeficiency Virus