Synthesis and Characterization of Clickable Peptide-Oligonucleotide Conjugates

Chemicals were purchased from Sigma-Aldrich and anhydrous organic solvents were Aldrich's Sure/Seal™. DBCO-NHS ester was purchased from Click Chemistry Tools. Peptides were custom synthesized by CPC Scientific (San Jose, C, USA) and oligonucleotides (PolyT₂₀) with a C12 amino modifier at its 5′-end by IDT (Integrated DNA Technologies). 1H and ¹³C NMR spectra were recorded at 400 MHz (^{1 (link)}H), 100 MHz (^{13 (link)}C), respectively. Chemical shifts are given in parts per million (ppm) on the delta scale (δ) and are referred to the solvent residual peak. HPLC analysis and purification were carried out in Agilent 1100 series equipped with a UV detector and a fraction collector. A Zorbax Eclipse Plus C18 column (4.6 × 150 mm, particle size 5 μm) from Agilent was used for the reversed phase HPLC. MALDI-TOF analysis was performed on Voyager-DE STR instrument.