The human body is made up of nearly 50 trillion cells – with more than 40 million molecules in each cell. Understanding how those molecules work is necessary for understanding life, but also for understanding, predicting and curing disease. But molecules are too small to see directly. Studying those molecules in detail – structural biology – is made possible by a variety of techniques. Using a technique called X-ray diffraction , we can study the atomic structure of molecules. To do this, the molecules are first crystallized. The crystals are then placed in full-strength X-rays, generated by so-called synchrotrons. A synchrotron accelerates particles to a very high speed, and uses them to make very strong X-rays. With X-rays we can see how atoms are in the crystallized molecules. But due to recent advances in cryo-electron microscopy , we can now also study large complex biological molecules. First we freeze them in a thin layer of a solution, then we use a powerful electron microscope to take images of them. Multiple images are then combined into three-dimensional structures, allowing us to see the exact location of each atom in the molecule. The images created with X-rays and cryo-EM are mainly static. To fully understand how molecules work , we also need to understand their interactions and movement.
To do that, we use X-ray scattering, visible light, or a method called nuclear magnetic resonance. This allows us to directly see the movement of molecules in solution. The molecules are placed in a strong magnetic field and between radio waves, which causes the atoms in them to emit high-frequency signals. We can measure those signals and use them to determine the details of the movement. Structural biology can also be used to study cells. That gives us pictures of how the different molecules are inside the cells, and shows how the molecules interact. These techniques are so important that the European Union provides funding to facilities with the necessary equipment – enabling researchers across Europe to conduct their experiments in the best possible way.