Molecular engines under a magnifying glass. The world’s first such comprehensive study

Molecular actuators are wonderful structures that convert chemical energy into mechanical work. Scientists are getting close to deciphering their actions.

Molecular actuators convert energy into useful work. scientists z CSSB Center for Structural Systems Biology at DESY The University Medical Center Hamburg-Eppendorf (UKE), led by Thomas C. Marlowitz, revealed the architecture, full-functional cycle and mechanism of action of the molecular motor. This achievement was reported in the magazine temper nature.

What are molecular motors?

DNA recombination is one of the basic biological processes in living organisms. In this process, chromosomes “exchange” DNA to generate genetic diversity by creating new offspring, or to maintain genetic integrity by repairing breaks in existing chromosomes. During DNA recombination, the four arms of DNA separate to form the double helix and join at a junction known as the Holliday junction. Here, DNA strands are exchanged in a process called crossing over (homologous recombination).

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The energy needed for this recombination to occur comes from a molecular motor that the scientists call the RuvAB recombination complex. This complex is assembled around the Holliday junction and consists of two motors, called RuvB AAA + ATPases, which drive the reaction, and RuvA proteins. The research team has now provided a blueprint that explains how RuvB AAA+ motors operate under the control of the RuvA protein to perform synchronous DNA movement.

Active homologous recombination catalyzed by the RuvB AAA+ molecular motor is very fast and highly dynamic. We used time-resolved cryo-electron microscopy to identify the different steps in this process. Essentially, we fueled the RuvB AAA+ engine with slower-burning fuel, which allowed us to capture biochemical reactions as they occurred.Thomas C. Marlowitz

Scientists have captured more than 10 million images of the molecular motor interacting with the Holliday junction. We were able to visualize this process on film.

AAA+ motors are often used in other biological systems such as protein transport, so this detailed motor model can be used as a blueprint for similar molecular motors.