Efficient Formation of Site-Specific Protein–DNA Hybrids Using Copper-Free Click Chemistry

Protein-DNA hybrids have become increasingly popular molecular building blocks in bionanotechnology and single-molecule studies to synergistically combine the programmability of DNA with the chemical diversity of proteins. The growing demand for protein-DNA hybrids requires powerful strategies for their conjugation. Here, we present an efficient two-step method for protein-DNA assembly based on copper-free click chemistry. The method allows site-specificity and high coupling efficiency, while maintaining the conservation of protein activity. We compare our method to a commonly used protocol of direct linkage of maleimide-modified oligos. We demonstrate the significantly higher yield with a protein-DNA conjugate, which is analyzed using single-molecule force spectroscopy.