Determination of the structure of biological macromolecular particles using X-ray lasers. Achievements and prospects

X-ray diffraction analysis is the main experimental approach to the determination of the atomic structure of biological macromolecules and their complexes. The most serious limitation of its applicability, which is caused by the extremely low intensity of the rays scattered by a single molecule, today, is the necessity to prepare a sample of the object under study in the form of a single crystal. The commissioning of X-ray free-electron lasers with their super-powerful (by many orders of magnitude exceeding the brightness of modern synchrotrons) and ultra-short (less than 100 fs) pulses is an experimental breakthrough, which allows us to expect to obtain diffraction patterns from individual biological particles and determine their structure. The first experimental results demonstrate the proof-of-principle of the approach and are accompanied by the publication of a large number of articles devoted to various aspects of the development of the method. The purpose of this review is to describe the current state of art in this area, evaluate the results achieved, and discuss the prospects for further development of the method based on the analysis of articles in the world scientific literature published in recent years and the experience of the authors and their colleagues.