One efficient method for understanding how small things are integrated in bigger ones has revolutionized structural biology in the past few years: cryo-electron microscopy. Its name derives from the ancient Greek words κρύος (kríos, for cold), μικρός (mikrós, for small), and Σκοπιά (skopia, too look or look-out). The development of this technique over the last decades was honored with the 2017 Nobel Prize in chemistry.
A vitrified biological sample (of macro-, micro-, or nanometer size) is subjected to a high-energy electron-beam (300 kV) at -190 °C and high vacuum. The electron beam passes through the sample and a series of lenses and filters and finally hits a camera. Thereby, the electron beam penetrates the specimen and thus it is possible to visualize the interior layers of a sample, and not only its surface. In modern microscopes, the sample can furthermore be rotated resulting in cryo-electron tomography.
Cryo-electron tomography allows scientists to visualize and display 3-dimensional structures of biomolecules in high resolution. This knowledge of the structure and organization of proteins facilitates the development of drugs used to treat a variety of illnesses, from cancer to Alzheimer’s disease.
Bruno Martins is a PhD-student in the Research Group of Prof. Ohad Medalia at the Biochemical Institute at the University of Zurich. More