The Structure Explosion

A glance at the current literature quickly reveals the extent to which crystallography has become an essential component of both chemistry and biology. New structures emerge at an ever-increasing rate, fuelled both by technical advances in sources, detectors and computing, and by new and improved structural methods. This trend can only increase, with CCD detectors coming into wide use, and the various genome projects giving further impetus to biological crystallography.

This situation is obviously very gratifying to crystallographers. We are needed! It also fulfils the belief of pioneers such as Dorothy Hodgkin, that crystallography would liberate chemistry and biology from the burdens and uncertainties of structure determination by more "sporting" methods.

The explosion of new structures brings stresses, however. One is the pressure of publication space in journals that are already under pressure to contain costs. A single laboratory with a CCD detector could easily determine more than 300 structures in a year and submit them all to Acta Crystallographica! Another is the importance of establishing quality. These can be in conflict, for example in a biological journal where space restrictions may result in the omission of valuable quality indicators.

New modes of publication will be essential to meet the first of these pressures. There must also be debate as to what constitutes a publication. Will entry of a structure in a database count for promotion committees, grant reviews and the like? It is in this context that Acta C offers its new "CIF-access" mode of publication. This allows a structure to be announced in the journal and validated, but without written publication of text or data. This mode offers strict data checking, rapid publication, no restrictions on authors' comments in the CIF, and convenient electronic access.

Finally, the crucial issue of quality. Quality must not be sacrificed as structural analysis becomes faster and easier. A "moderate-quality" structure may answer some questions today, but the data will later be used by others to answer new, possibly more demanding questions. The validation checks of Acta C are therefore critical for adding value to the structural data. In macromolecular crystallography the issue is no less important, and probably more challenging. Present debate on the quality of macromolecular structures, on methods of validation, and on proper ways of refining at less than optimal resolution, is of great importance to the field. It is of even more importance when one thinks of the many non-crystallographers who will be seeking to use our results!