Protein Tethering for Single-Molecule Force Spectroscopy.

Molecular manipulation by optical tweezers is a central technique to study the folded states of individual proteins and how they depend on interactions with molecules including DNA, ligands, and other proteins. One of the key challenges of this approach is to stably attach DNA handles in an efficient manner. Here, we provide detailed descriptions of a universal approach to covalently link long DNA tethers of up to 5000 base pairs to proteins with or without native cysteines.