Axima lnr

A coupling reaction between amino-modified ODNs (100 μM) and Alexa Fluor 488 NHS ester or succinimidyl derivative of protein tag substrates (1 mM) was carried out in 100 mM phosphate buffer (pH 8.0) for 8 h at ambient temperature. The modified ODNs were purified by reversed-phase HPLC on a Cosmosil 5C18-MS II column (4.6 × 150 mm, eluted with 100 mM triethylammonium acetate buffer, pH 7.0, with a linear gradient over 30 min from 2.5% to 30% acetonitrile at flow rate of 1.0 mL min^–1) and characterized by MALDI-TOF mass spectrometry (AXIMA-LNR, Shimadzu, HPA matrix). A488-ODN-ZF: m/z calcd 11 397, observed 11 395; A488-ODN-AZ: m/z calcd 11 400, observed 11 399; A488-ODN-AP: m/z calcd 12 011, observed 12 014. ODN-AP-2BC: m/z calcd 12 290, observed 12 290, ODN-8G-AP-2BC: m/z calcd 21 577, observed 21 578, ODN-11G-ZF-BC: m/z calcd 21 160, observed 21 167, ODN-ZF-BC: m/z calcd 14 287, observed 14 287, ODN-ZF(G/T)-BC: m/z calcd 14 286, observed 14 289, ODN-ZF(G/C)-BC: m/z calcd 14 287, observed 14 282, ODN-ZF(GG/TC)-BC: m/z calcd 14 286, observed 14 288, and ODN-ZF(GG/TC)-BC: m/z calcd 14 286, observed 14 291. The method for preparing ODN-AZ-BC, ODN-AZ-BG, and ODN-24D-AZ-BC was described in a previous report.15 (link)

A volume of 400 µM of Thiol-modified DNA oligonucleotides were treated with 10 mM TCEP (tris(2-carboxyethyl)phosphine) in 40 mM phosphate buffer (pH 8.0) for 30 min at room temperature and reacted with 8 mM of DOPE-MAL containing 2% OG overnight. The reaction mixture was purified by reverse-phase HPLC on a Cosmosil 5C18-MS II column (4.6 × 150 mm, eluted with 0.1 M TEAA (triethylammonium acetate) buffer, pH 7.0, with a liner gradient over 10 min from 52 to 75% acetonitrile at a flow rate of 1.0 mL·min⁻¹) and characterized by MALDI-TOF mass spectrometry (AXIMA-LNR, Shimadzu, Kyoto, Japan) (HPA matrix). Lipidated ODN: m/z calcd 7637, observed 7640.