Download citation
Acta Cryst. (2014). A70, C10
Download citation

link to html
I will give an overview of synchrotron radiation (SR) in macromolecular crystallography (MX) instrumentation, methods and applications from the early days to the present, including the evolution of SR sources and on to the `ultimate storage ring'. The build of dedicated beamlines for resonant anomalous scattering, large unit cells, ever smaller crystals and studies up to ultra-high resolution are core benefits. Results include a high output of PDB depositions, the successful use of microcrystals, pushing the frontiers of using high and low photon energies and time-resolved structural studies at even sub-nanosecond resolutions. These intensively physics based developments will be complemented by biological and chemical crystallography research results, encompassing catalysis and marine coloration, as well as the public understanding of our science and its impacts. Spin off benefits include services to the pharmaceutical industry and helping develop chemical crystallography uses of SR. The development of the Laue method with SR has led to pioneering spin off developments in neutron MX, including transfer of the well validated Daresbury Laue software to various neutron facilities worldwide. Neutron MX is gathering pace as new instrumentation and dedicated sample preparation facilities are in place at reactor and spallation neutron sources; smaller samples and much larger molecular weight protein complexes are now feasible for investigation so as to establish their protonation states and bound water structure. With the X-ray lasers, closely linked to the SR developments, we anticipate the use of ever smaller samples such as nanocrystals, nanoclusters and single molecules, as well as opening up femtosecond time-resolved diffraction structural studies. At the SR sources, a very high throughput assessment for the best crystal samples and tackling sub-micron crystals will become widespread.

Download citation
Acta Cryst. (2014). A70, C497
Download citation

link to html
We have established a user knowledge base centred in Bangalore, but obviously accessible from anywhere in the world, for displaying ion pair distances for any protein deposited in the Protein Data Bank. We have published a description, its theoretical basis and examples of its use in IUCrJ [1]. The special characteristic is that the precisions on these distances is also displayed. These are based on the Diffraction Precision Index (DPI) approach [2] adapted to the pair of atoms involved in the non-covalent interaction and their specific B factors. Thus the display of the true precision can readily be seen by the user. We described other situations [1] where this approach could be used namely where restraints of a protein model refinement are not used such as metal ligand sites in proteins and protonation state determinations i.e. where a bond distance restraint is explicitly removed. We will report firstly on the ion pairs knowledgebase, as recently published, but with more examples from the user point of view. This will include a discussion of the range of precisions of the protein structures in the PDB as exemplified by using the DPI. Secondly, progress towards a knowledgebase, again including precision, for metal ligand interactions in the structures of metalloproteins and nucleic acids will be described.
Follow Acta Cryst. A
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds