Maleimide Deprotection for Oligonucleotide Conjugation

<p>Bio-Synthesis offer two types of maleimide functionalize oligo&nbsp;</p><ul> <li><strong>Protected</strong> Maleimide by direct chemical synthesis</li> <li><strong>Ready-to-Use</strong> maleimide modified oligo</li></ul><p>The maleimide-functionalized oligonucleotide is supplied in a <strong>protected form</strong> and must undergo <strong>Retro Diels&ndash;Alder deprotection</strong> prior to conjugation. This reaction requires <strong>anhydrous conditions</strong>, as moisture can cause <strong>incomplete deprotection, hydrolysis</strong>, or <strong>undesired side reactions</strong> with the maleimide group.</p><p>The process involves co-evaporation with anhydrous acetonitrile and toluene, followed by thermal activation. After completion, the product forms a white residue ready for conjugation.</p><p><strong>Below is an abbreviated protocol for deprotection procedure</strong></p><ol> <li><strong>Suspend</strong> the lyophilized oligonucleotide in <strong>1.0 mL anhydrous acetonitrile</strong>. (Note: The oligo will remain as a suspension and will not fully dissolve.)</li> <li><strong>Evaporate</strong> the suspension to dryness using a <strong>speedvac</strong>.</li> <li><strong>Resuspend</strong> the dried oligo in <strong>1.5 mL anhydrous toluene</strong>.</li> <li><strong>Incubate</strong> the solution at <strong>90 &deg;C for 4 hours</strong> under anhydrous conditions.</li> <li><strong>Cool</strong> the reaction mixture to room temperature.</li> <li><strong>Evaporate</strong> the toluene completely using a <strong>speedvac</strong>.&nbsp;</li> <li>The oligonucleotide is now <strong>ready for conjugation</strong> to thiol-containing molecules via the exposed maleimide group.</li></ol>