One hundred years of X-ray diffraction, 50 years of structural biology

Since the pioneering diffraction experiments led by Max von Laue in 1912, X-ray crystallography has progressed with a spectacular pace, opening research, and application perspectives in fields such as materials science, chemistry, mineralogy, environmental sciences, biotechnology and biomedicine. Such developments have been supported by discoveries in both the theoretical and experimental branches of science that granted the different communities access to specific investigation tools. In the biological field the highest challenge presented to X-ray crystallography has been linked to the study of proteins and nucleic acids, i.e., macromolecular structures composed of thousands of atoms, often available for the analyses in microscopic crystals of low intrinsic order. To support the development of macromolecular crystallography several complementary techniques had to be devised, such as methods in biochemistry and molecular biology, but also progresses in synchrotron X-ray sources. As the contemporary crystallographic methods allow facing very complex protein structures, in relatively short response times, the interest of corporate research for applied crystallography has grown substantially in the last two decades. In particular, current approaches to drug discovery and optimization rely on rational principles that stem from crystallographic investigations on protein/lead complexes, and on cyclic optimization of their chemical synthesis. Notably, the United Nations declared 2014 the International Year of Crystallography in consideration of the fundamental role played by crystallography for the growth of scientific knowledge.