Abstract
Magnetic tweezers (MT) have become an important single-molecule manipulation tool, with several advantages over alternate methods such as optical tweezers and atomic force microscopy. MT are easy to operate, cost effective, and can apply forces ranging from sub-piconewton (~ 0.1 pN) to hundreds of piconewtons. Furthermore, they offer exceptional spatial and temporal resolution. These features position MT as a versatile and powerful tool to study many biomolecular processes at the single-molecule level. MT have played an important role in advancing our understanding of DNA–protein interactions, making significant contributions across molecular biology, enzymology, and chromatin dynamics. In this review, we start by describing principal MT geometries along with force calibration methods and then pivot to a discussion of MT-based studies of DNA mechanics, chromatin organization, nucleosomes, nucleoid-associated proteins, topoisomerases, helicases, and polymerases. We aim to provide the research community with an integrated overview of MT-based approaches to studying DNA–protein interactions, highlighting both foundational work and recent innovations that continue to shape the field of single-molecule biophysics.