A Molecular Machine in Action

X-ray imaging reveals a motor-like biological protein at work, helping researchers develop antibiotics.

Nov 19, 2009

Researchers at the Lawrence Berkeley National Laboratory have used advanced imaging techniques to solve the structure of one of nature’s most important molecular machines. A clearer picture of this motor-like protein, which spins along strands of bacterial messenger RNA to read and translate it into proteins, may help pharmaceutical researchers develop new antibiotics. The researchers studied a version of the protein called Rho from E. coli bacteria. This type of protein, called a transcription factor, is also important in human development and disease.

In the video below, Rho, which is shaped like a hexagon with a hole in the center, is shown in cross section as it walks along the RNA strand, shown in orange. Rho spirals in such a way that it can only move in one direction along the RNA strand, which is crucial to making proteins properly.

In order to get a better picture of Rho, the Berkeley researchers used the lab’s Advanced Light Source, which accelerates electrons to very high energies in order to create some of the brightest x-rays in the world. Using these x-rays, they were able to see a part of Rho’s structure that was previously not very well understood.