What Can the Current X-Ray Structure Analysis Offer?

Abstract

X-ray diffraction analysis is still the most important method for crystal structure determination. It is used in crystallography of small molecules and proteins. Although principles of both applications are the same, they differ in methodology of crystallization and utilization. The main limiting factor of progress is the preparation of single crystals. This article reviews current methods and trends, as presented at the last European Crystallographic Meeting and Congress of the International Union of Crystallography. The crystallography of small molecules tends towards solving structures from powder diffraction data, studying structural changes in chemical reactions in situ and describing detailed structure (aperiodic crystals). The advanced “charge-flipping” method for the phase problem solution is mentioned. In protein crystallography, solving crystal structures is easier with novel procedures for protein supply, crystallization tests, and data collection using common and synchrotron x-ray sources as well as advanced computational methods of phase determination and model refinement. The solved protein structures are exemplified with several “molecules of the month” in the Protein Data Bank, emphasis being put on structural basis of pathological mechanisms and the use of crystal structures in design of drugs and biopharmaceuticals. Ab initio predictions and simulations of crystal structures are discussed.