Welcome to the

International Union of Crystallography

The IUCr is an International Scientific Union. Its objectives are to promote international cooperation in crystallography and to contribute to all aspects of crystallography, to promote international publication of crystallographic research, to facilitate standardization of methods, units, nomenclatures and symbols, and to form a focus for the relations of crystallography to other sciences.

New Year's Message from the IUCr President

We look forward to your continued support of our collective mission to promote and advance crystallography around the world. We continue to build on the success of the IYCr with further support for OpenLabs in Asia, Africa and Latin America. This is made possible by generous donations to the IYCr Legacy Fund. For details of this Fund and how to donate, please click here.

Marvin L. Hackert

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Eleventh Ewald Prize – Call for Nominations

[Ewald Prize medal]The International Union of Crystallography is pleased to invite nominations for the Ewald Prize for outstanding contributions to the science of crystallography. The Prize is named after Professor Paul P. Ewald, in recognition of his significant contributions to the foundations of crystallography and to the founding of the International Union of Crystallography. Professor Ewald was the President of the Provisional International Crystallographic Committee from 1946 to 1948, the first Editor of the IUCr publication Acta Crystallographica from 1948 to 1959 and the President of the IUCr from 1960 to 1963.

The Prize consists of a medal, a certificate and a financial award, and is presented once every three years during the triennial International Congresses of Crystallography. The recipients to date are as follows:

  
Year Place Recipients
1987 Perth, Australia Professor J.M. Cowley and Dr A.F. Moodie
1990 Bordeaux, France Professor B.K. Vainshtein
1993 Beijing, People's Republic of China Professor N. Kato
1996 Seattle, USA Professor M.G. Rossmann
1999 Glasgow, UK Professor G.N. Ramachandran
2002 Geneva, Switzerland Professor M.M. Woolfson
2005 Florence, Italy Professor P. Coppens
2008 Osaka, Japan Dr D. Sayre
2011 Madrid, Spain Professor E. Dodson, Professor C. Giacovazzo and Professor G.M. Sheldrick
2014 Montreal, Canada Professor A. Janner and Professor T.W.J.M. Janssen

The eleventh Prize, for which nominations are now being invited, will be presented at the Hyderabad Congress in August 2017.

Scientists who have made contributions of exceptional distinction to the science of crystallography are eligible for the Ewald Prize, irrespective of nationality, age or experience. The Selection Committee will give careful attention to the nominations of outstanding scientists who have not yet won a Nobel Prize. Either an exceptionally distinguished scientific career or a major scientific accomplishment may be recognised. Current members of the Selection Committee and the President of the IUCr are not eligible. No restrictions are placed on the time or the means of publication of the nominee's contributions. The Prize may be shared by more than one contributor, but not more than three, to the same scientific achievement.

Nominations for the Ewald Prize should be submitted electronically using the Ewald Prize Nomination Form, to the Executive Secretary of the International Union of Crystallography, 2 Abbey Square, Chester CH1 2HU, England (execsec@iucr.org). Copies of the Nomination Form and the names of the Selection Committee may be obtained from http://www.iucr.org/iucr/ewald-prize. The closing date for nominations is 31 August 2016.

Posted 02 Feb 2016 

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Nucleoprotein C-terminal domain from the Ebola and Marburg viruses

Ebolavirus and Marburgvirus belong to a virus family called Filoviridae and can cause severe hemorrhagicgm5041 fever in humans. The outbreak of Ebola virus disease (EVD) in West Africa demonstrates the grave threat that these viruses pose globally to human health. While the EVD outbreak is slowly losing momentum, it is still unprecedented, resulting in over 23 000 cases and more than 9000 deaths by late 2015.

There are two species of Marburgvirus (MARV and RAVV) and five species of Ebolavirus (Zaire, Reston, Sudan, Taï Forest and Bundibugyo) within the Filoviridae family of negative-sense, single-stranded RNA (ssRNA) viruses. In each of these viruses the ssRNA encodes seven distinct proteins. One of them, the nucleoprotein (NP), is the most abundant viral protein in the infected cell. It is tightly associated with the viral RNA in the nucleocapsid and is essential for transcription, RNA replication, genome packaging and nucleocapsid assembly prior to membrane encapsulation.

Until recently, the nucleoprotein was one of two proteins encoded by the Ebolavirus genome, that have not yet had their structures characterized. Since this protein is critical for the assembly and replication of the virus, it is recognised as a suitable drug target. Recently a group of scientists [Baker et al. (2016). Acta Cryst. D72, 49-58; doi: 10.1107/S2059798315021439] have shown that the homologous C-terminal domains of NP from two related pathogenic species of Ebolavirus, Taï Forest and Bundibugyo, have structures that are highly similar to that of a Zaire variant, in spite of differences in the amino-acid sequence. Interestingly, the related NPCt domain from MARV has a structure that is significantly different from the Ebolavirus consensus structure.

In addition, structural characterization of NPCt from the different Ebolavirus species is important since the Ebolavirus NPCt has also been identified as a possible target for the development of species-specific diagnostic tests.

Posted 28 Jan 2016 

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2016 Alexander Hollaender Award in Biophysics

[Richard Henderson]Richard Henderson, member of the scientific staff in the MRC (Medical Research Council) Laboratory of Molecular Biology in Cambridge, UK, and editorial advisory board member of the open-access journal IUCrJ, will receive the 2016 Alexander Hollaender Award in Biophysics.

In 1975, Henderson and colleague Nigel Unwin determined the structure of bacteriorhodopsin - a light-driven proton pump found in the membrane of Archaea - using electron microscopy. This was revolutionary because the technique usually requires a stain that can obfuscate details, but Henderson and Unwin realized they could instead place the crystals on a thin carbon support and eliminate the stain. Starting in the 1990s, Henderson again revolutionized the field of structural biology when he turned his sights on another method for determining protein structure: cryoEM. In this technique, proteins are flash-frozen by plunging into liquid ethane then imaged with electron microscopy. Henderson and others made major improvements to the method - developing better sensors for electron microscopes, as well as better software for the system - that improved cryoEM to such an extent that it is now the preferred technique for determining protein structures.

The Alexander Hollaender Award in Biophysics is presented every three years and carries with it a $20,000 prize. The Award recognizes outstanding contributions made to the field of biophysics.

This article is a short extract reprinted from a press release published on the National Academy of Sciences website.

Posted 26 Jan 2016 

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Digital enhancement of cryoEM photographs of protein nanocrystals

[me0605]When cryoEM images are obtained from protein nanocrystals the images themselves can appear to be devoid of any contrast. A group of scientists from the Netherlands has now demonstrated that lattice information can be revealed and enhanced by a specialized filter.

The procedure described by van Genderen et al. [(2016). Acta Cryst. D72, 34-39; doi: 10.1107/S205979831502149X] paves the way towards full three-dimensional structure determination at high resolution for protein crystals. The authors report on how lattice information can be enhanced by means of a wave finder in combination with Wiener-type maximum-likelihood filtering. The lattice filter is a very powerful tool for selecting and analysing extremely low contrast cryo-images of three-dimensional protein/peptide nanocrystals. It confirms that the three-dimensional crystals are made up from multiple domains that are slightly differently oriented. Indeed, the algorithm can comfortably deal with multiple crystals with very different orientations, unit cells and/or space groups.

The authors of the paper propose the new lattice filter as a powerful tool for processing very noisy images with crystal factors (and thus the phase information) hidden within them. The filter is able to discriminate between noise images and the very noisy images with very low contrast which contain crystal-like structures. The lattice filter retains the shape of the spots in Fourier space and also retains any phase gradients within the Bragg spots (which determine the domain structure within the crystal). Thus, it retains all of the significant information from the Bragg spots. This will open the way to combining the phases acquired from stationary, two-dimensional images with intensities of rotation diffraction data taken from the same type of crystals. In this way, the authors expect to be able to phase the diffraction information of protein and peptide crystals.
Posted 21 Jan 2016 

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Introducing CIF 2.0

[#\#CIF_2.0]Two papers in the current Journal of Applied Crystallography give a specification of an updated Crystallographic Information File format, and describe an accompanying application programming interface (API) and reference implementation. The CIF2.0 format was formally approved by the maintenance committee COMCIFS in August 2014, and the paper of Bernstein et al. (2016) represents the first formal publication of the new file format. The CIF API of Bollinger (2016) provides software developers with tools for using the new format, for validating the syntax of their files against the new standard, and for converting data files between old and new formats if required.

Since CIF was designed from the outset as an archival format, publishers and databases will continue to support the existing CIF1.1 format indefinitely. It is not expected that any existing CIF-writing software will need to change in the immediate future.

So what is the purpose of the new specification? It introduces a number of novel features, such as the Unicode character set to handle data internationalization, and complex data types which can make it easier to handle vector or matrix objects. A particular benefit is that it will allow relationships between data items to be defined using methods expressions in future CIF dictionaries, opening the way to more powerful automatic validation of the contents of a data file, and this is likely to be the first area in which the new format will be used. The timescale for applying CIF 2.0 features to the data files themselves will depend very much on the desire of individual communities to take advantage of the potential benefits of the new format.

We would encourage software developers with an interest in these new features to become familiar with the website cif2.iucr.org, and consider signing up to the cif-developers mailing list (www.iucr.org/lists/cif-developers) or the new CIF2 forum soon to be launched at forums.iucr.org.

James Hester
Chair, COMCIFS
Posted 23 Dec 2015 

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CryoEM at IUCrJ: a new era

[Brome mosaic virus structure]Since 2012, the advent of new electron detectors and improved computational programs together with substantial improvements in the electron microscopes themselves has produced an avalanche of new publications and coordinate depositions in the Electron Microscopy Data Bank (EMDB) and the Protein Data Bank (PDB). The productivity and power of the method has attracted many newcomers, from cell biologists who have a more biological emphasis, to those from adjacent disciplines such as crystallography and NMR spectroscopy who already have extensive depth of experience in structural biology. The recent successes span a wide range and include small proteins, as well as flexible and multi-domain protein complexes, several of which have proved to be resistant to analysis by X-ray crystallography over the years. Further, the level of automation in all aspects of the workflow has increased, making it easier for new users to adopt the method and to use it successfully.

A brief overview of advances in cryoEM can be found in Subramaniam et al. (2016). IUCrJ 3, 3-7; doi: 10.1107/S2052252515023738. An overview of the advances of cryoEM cannot be completed without mentioning the achievements and potential of electron cryotomography (cryoET). The application of cryoET to understand the macromolecular architectures of eukaryotic cells has shown that this method has enormous potential for investigating structures at the sub-cellular level. It is also possible to carry out sub-tomogram averaging in three dimensions to improve the resolution of structure determination of structures that are found in multiple copies in each tomogram. In principle, the averaging of sub-tomogram volumes should eventually produce maps at resolutions comparable to those produced using single particle cryoEM methods.

During the next few years, we expect that technical advances will make cryoEM more powerful and versatile than it is at present. We anticipate that further advances will occur in detector technology, phase plates, Cc correctors, computing power and algorithms, design of better specimen supports, and improved imaging strategies, although there are unsolved problems in each of these areas that might take a few years to overcome.

We hope that IUCrJ will be a key journal that can ride the wave of all the expected (and unexpected) technical advances that we believe will continue to make cryoEM methods even more powerful in the coming decade. The journal can act as a vehicle to publicise these advances and help the cryoEM field to move forward coherently. CryoEM itself may become the first choice method at the start of any structural biology project, since it requires a smaller quantity of material that is less pure, less stable and less homogeneous than needed for many other methods. It may even become the dominant method in structural biology in the future.

Richard Henderson, Werner Kühlbrandt and Sriram Subramaniam

This article is a short extract reprinted from an article published in the journal IUCrJ

Posted 14 Jan 2016