The active branch migrations energized by the RuvB AAA+ motor molecule are very fast and highly dynamic. The research team has now provided an intricate blueprint that explains how the RuvB AAA+ motors work under the regulation of the RuvA protein to perform synchronized DNA movement.

This complex assembles around the Holliday junction and is made of two motors labelled RuvB AAA+ ATPases, that fuel the reaction, and a RuvA stator. The essential energy needed for this branch migration to occur comes from a molecular machinery that scientists have tagged as the RuvAB branch migration complex. Here the DNA arms exchange strands in a process called active branch migration. During DNA recombination, four DNA arms separate from their double-helix formations and join together at an intersection known as a Holliday junction. It is the process by which chromosomes 'swap' DNA either to generate genetic diversity, by creating new offspring, or to maintain genetic integrity, by repairing breaks in existing chromosomes.

DNA recombination is one of the most fundamental biological processes in living organisms. Marlovits from the Centre for Structural Systems Biology CSSB at DESY and the University Medical Center Hamburg-Eppendorf (UKE) in Hamburg reveals the architecture, complete functional cycle and the mechanism of such a molecular motor: They report in the journal Nature, how a 'RuvAB branch migration complex' converts chemical energy into mechanical work to perform recombination and repair of DNA.

Final print mechanicals