Carrasco C, Gilhooly NS, Dillingham MS, Moreno-Herrero F.
We report the use of the magnetic tweezers approach to monitor the dynamics of double-stranded DNA break resection at single-molecule resolution. In this work, we unveil the inner workings of the Bacillus subtilis AddAB complex by showing that the domain responsible for the recognition of the recombination hotspot sequence Crossover hotspot instigator (Chi) antagonizes the translocation activity, causing the complex to transiently stall at Chi and Chi-like sequences.
We propose a simple model for failed and successful Chi recognition in which the battle between the translocation and sequence-specific binding activities acts as a selectivity filter for bona fide Chi sequences.