Selection of antibody-binding covalent aptamers

Aptamers are oligonucleotides with antibody-like binding function, selected from large combinatorial libraries. In this study, we modified a DNA aptamer library with N-hydroxysuccinimide esters, enabling covalent conjugation with cognate proteins. We selected for the ability to bind to mouse monoclonal antibodies, resulting in the isolation of two distinct covalent binding motifs. The covalent aptamers are specific for the Fc region of mouse monoclonal IgG1 and are cross-reactive with mouse IgG2a and other IgGs. Investigation into the covalent conjugation of the aptamers revealed a dependence on micromolar concentrations of Cu