The analysis of protein structures: New insights from a growing data base

We now know the structures of over 200 proteins to atomic resolution. Despite the impressive extent and quality of the results, crystal‐structure analysis has often been thought of as limited in scope, not only in its restriction to samples that can be crystallized, but in the more important respect that taking ‘snapshots’ of proteins does not directly address the complex spatio‐temporal organization of the processes in which proteins participate. It is suggested here that, as the field has matured, this second limitation is gradually being overcome. As we gain increased access to structures of proteins in different conformational states – for example, in conformations produced by different states of ligation – and to families of homologous proteins, we can proceed from the statics of protein structure to the dynamics of conformational change, function, and evolution. A new scientific speciality has grown up around the solved structures: it has as its goal the elucidation of general principles of protein structure and function, to provide a theoretical framework for understanding the properties of proteins revealed by experiment. In this article we shall discuss some of the activity in this field. It will emerge clearly, I believe, that the increasing number and variety of solved structures is exerting a cumulative force. General principles are emerging from comparisons of related proteins and contrasts of dissimilar ones: the whole corpus of data is greater than the sum of the parts.