Current advances in the X-ray crystallography of proteins

The present state and prospects for the development of the X-ray crystallography of globular proteins are analysed. The mechanisms of the functioning of membrane receptors, the immune proteins of T-lymphocytes, the histone octameric core of nucleosomes, DNA topoisomerase, the aspartate proteases of retroviruses, and the proteins of the actomyosin complex of skeletal muscles are examined on the basis of the three-dimensional structures of the protein molecules which have become known in recent years. It is shown that the results of the X-ray diffraction analysis of proteins has played a decisive role in the creation of an experimental basis and the development of the approaches necessary for the establishment of theoretical biology. A large proportion of the review is devoted to the advances in X-ray crystallography as regards the sources of radiation, the phase problem, and the experimental conditions. The use of synchrotron radiation and the abandonment of multiplet isomorphous substitution in the determination of phases not only significantly simplify the study of the molecular structures of proteins but permit an approach to securing information about the structures of protein intermediates which had previously been inaccessible. The bibliography includes 324 references.