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Editorial

This issue of the IUCr Newsletter contains reports from the XVI Congress and General Assembly of the IUCr, August 20-29, 1993. The reports are based upon material provided by program committee members, the chairs of plenary lectures, microsymposia, discussion sessions, open commission meetings and some roving reporters.

Due to logistical problems not all session chairs received requests for reports and some of those contacted did not file reports. If you attended the Beijing Meeting and find that the meeting reports fail to mention a session or presentation that you considered especially noteworthy, I invite you to correct the record with a 'Letter to the Editor'. If you think your own presentation was particularly noteworthy, I recommend that you persuade a colleague to bring this to our attention so as not to appear self-serving. I wish to express appreciation to E. Adman, P. Barnes, J. Baruchel, P. Bordet, I. D. Brown, A. Brünger, D. Dorset, J. Glusker, J. Janin, F. Liebau, P. Luger, D. Stuart and D. Schwarzenbach for contributions that were particularly helpful. R. Bryan's summary of the Transactions of the General Assembly and the summary reports of H. Einspahr and B. Wuensch were taken from the ACA Newsletter. Unless otherwise noted all photographs in this issue were taken by the Editor.

Financial constraints limit the length of the Newsletter to 32 pages. More articles have been submitted since the publication of the last issue than could be accommodated. Consequently, meeting reports on Crystal Growth in Microgravity (USA), Crystallography of High-T Superconductors (Italy), Modern Aspects of Small Angle Scattering (Italy), Powder Diffraction School (Venezuela), Compton Scattering and Fermiology (Poland), the Denver Diffraction Conf. (USA), and the Fifth Int'l Conf. on Crystallization of Biological Macromolecules (USA) have been set aside for publication when space permits.

Advertising

Additional advertising will make it possible to expand the Newsletter and include more information of interest and value to the crystallographic community. The Newsletter is an ideal vehicle to advertise diffraction equipment and supplies, computer hardware, graphics terminals and workstations, equipment for protein isolation and purification, instruments for peptide and nucleic acid synthesis and sequence determination, textbooks, journals and teaching aids for structural chemistry and biophysics, software for protein sequence analysis, structure determination and refinement, database analysis, molecular modeling, and computational chemistry. If you can think of any companies that might benefit from advertising in the Newsletter please take the time to send us their names and addresses. We will place these names on a list to receive complimentary copies and invite them to advertise in the IUCr Newsletter. Please express appreciation to our advertisers for support which makes this service to you possible.

A section entitled "New Products" appears for the first time in this issue of the Newsletter. This section provides an opportunity for manufacturers to alert the crystallographic community to their latest products and services. "New Products" contributions of 200 words or the equivalent, if an illustration is included, should be addressed to the Editor.

Distribution

Delivery times for the Newsletter vary widely. Copies of the second issue posted in April found their way to Cuba in late October. Many countries in the International Union are taking bulk delivery from the printer in the US and then addressing individual copies to all crystallographers, potential advertisers, and other interested individuals within their country. In this way delivery is faster and the mailing list can be corrected, expanded, and maintained. Poland and Australia are the latest countries to undertake this mode of distribution.

In general, the names and addresses for distribution of the IUCr Newsletter are taken from the 1990 World Directory of Crystallographers. Unless a country agrees to accept bulk shipment or provides the publisher with a set of suitable mailing labels for their country, there is no way to correct or update the mailing list. The printer has received hundreds of returned copies with address corrections that they have in turn sent to me. Unfortunately, no mechanism or financial support for correcting the master file has been established and these corrections cannot be made.

Anyone desiring rapid delivery of the Newsletter in 1994 may wish to obtain air mail delivery at a cost of $20.00 to cover postage and special handling. Interested individuals should contact the Editor at the address on the masthead.

Crystallography and DNA

1993 marks the 40th anniversary of the publication of the Nature papers by Watson and Crick and Franklin and Wilkins describing the double helical structure of DNA. A number of symposia and celebrations have been held in Europe and the US marking the anniversary, and have provided the occasion for Watson and Crick to comment afresh on the circumstances surrounding the discovery, the excitement of the time, the impact their work has had upon biochemical and biomedical science, and what the future may hold. R. Franklin's tragic death and M. Wilkins' quiet humility have tended to eclipse the role that crystallography played in the original discovery.

Turn right at the TATA Box. The 80° turn introduced into DNA as a result of the binding of the TATA box binding protein (Kim et al., Nature 365, 512, 1993).

The latest of the major celebrations was held in Chicago, IL, USA, Oct. 14-16, 1993. More than a dozen biochemists who received Nobel prizes for research accomplishments made possible by the work of Watson, Crick, Wilkins and Franklin were on hand to describe their research.

One of the most exciting presentations was that of A. Klug (Nobel Prize in 1982), who focused on recent X-ray crystal structure studies of protein DNA complexes that are revealing the way in which the code in the double helix is unlocked and new protein synthesis triggered. He concluded his eloquent review with the most recent, remarkable and unexpected structure thus far, the TATA box binding protein (TBP) complexed with the TATA box. The thymine-adenine-thymine-adenine (TATA) sequence has long been recognized as critical to all transcription.

Crystal structures of the complex of yeast TBP and a 12 base pair duplex containing the TATA box of the CYC1 promoter (Kim, Geiger, Kohn & Sigler, Nature 365, 512, 1993) and the complex of the TBP from Arabidopsis thaliona with the TATA element from adenovirus major late promoter (Kim, Kinolov & Burley, Nature 365, 520, 1993) revealed an unexpectedly close association along the TATA sequence in the minor groove with partial unwinding and the introduction of an 80° bend in the double helix.

Even when the saddle-like structure of the TBP was revealed by X-ray analysis of the protein alone, over a year ago, no one predicted the kind of interaction revealed by these studies. In reference to the structures Klug points out that "They show dramatic changes in the conformation of the double helix the like of which have never been seen before in a DNA-protein complex."

The binding of the TBP to the TATA box is an essential component in the complex process of initiating the coding of new protein synthesis, and these structures allow us to see in molecular detail how transcription is initiated. It is satisfying to note that after 40 years X-ray crystallography continues to be the key to unlocking the most fundamental secrets of nature.

WLD


We are saddened to learn of the recent death of H. Rossell (CSIRO Victoria, Australia) and R. Pepinsky (USA). Obituaries will appear in a foture issue.