The Mre11/Rad50 (M/R) complex forms the core of an essential DNA-repair complex, conserved in all divisions of life. A Lancaster BLS/Cambridge collaboration has investigated this complex in the thermophilic archaeon Sulfolobus acidocaldarius using real-time atomic force microscopy. They demonstrate that the coiled-coil regions of Rad50 facilitate M/R interaction with DNA and permit substrate translocation and unprecedented unwinding of the DNA duplexes. The research published in PNAS provides a model for how the M/R complex can identify DNA double-strand breaks and orchestrate repair events.