Controlling electron beams with lasers to reveal protein structure

On a microscopic level, every function of life is performed by biological macromolecules. To understand how these molecular machines work, it is necessary to know the three-dimensional structure of their constituent protein complexes. Recently, a breakthrough in protein structure studies has been brought about by a series of technological advances in transmission electron microscopes, imaging tools that use electron beams to probe the specimen. However, biological macromolecules are nearly transparent to electron beams, which leads to weak image contrast and hampers the reconstruction of many proteins playing important roles in cellular processes. How can we extract all the information carried by the electrons that have passed through the specimen? In a recent experiment that brings quantum physics to the aid of molecular biology, we used high power laser beams to manipulate the electrons in order to maximize the image contrast of a transmission electron microscope.

Speaker: Osip Schwartz, UC Berkeley