Institute for Molecular Bioscience, University of Queensland, Queensland Bioscience Precinct, Brisbane, QLD 4072, Australia, Cambridge Institute for Medical Research, Department of Haematology, University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, United Kingdom, and Photon Science, SLAC and Structural Biology, School of Medicine, Stanford University, 2575 Sand Hi...

CHESS activity report F many years, most synchrotron stations for crystallography, such as CHESS A1, used X-ray sensitive film as the primary detector and xray radiation at about 8 keV (1.5 Å). Two years ago CHESS constructed station F1 on a wiggler line that is tuneable from about 7-14 keV. In practice, this station operates with a standard energy of 0.91 Å. The benefits of using higher energi...

The crystallography of icosahedral crystals is constructed. The actual three-dimensional crystal is represented by a three-dimensional cut in a regular six-dimensional periodic crystal with symmetry described by a six-dimensional space group, and the positions of atoms correspond to an arrangement of hypersurface segments. The resulting crystal can not in general be viewed as a space-filling ar...

Since the late 1950's, high-pressure structural studies have become increasingly frequent, following the inception of opposed-anvil cells, development of efficient diffractometric equipment (brighter radiation sources both in laboratories and in synchrotron facilities, highly efficient area detectors) and procedures (for crystal mounting, centring, pressure calibration, collecting and correctin...

A detailed model structure of dodecagonal quasicrystals is proposed which applies to both dodecagonal Ni-Cr and V-Ni or V-Si-Ni. This model structure can be represented as the restriction of a 5d periodic structure to a 3d subspace, which is identified with physical space. The point group and the space group of the 5d periodic structure are determined. The latter is non-symmorphic, containing a...

This essay describes the development of groups used for the specification of symmetries from ordinary and magnetic point groups to Fedorov and magnetic space groups, as well as other varieties of groups useful in the study of symmetric objects. In particular, we consider the problem of some incorrectness in Vol. A of the International Tables for Crystallography. Some results of tensor calculus ...

In macromolecular x-ray crystallography, refinement R values measure the agreement between observed and calculated data. Analogously, R(merge) values reporting on the agreement between multiple measurements of a given reflection are used to assess data quality. Here, we show that despite their widespread use, R(merge) values are poorly suited for determining the high-resolution limit and that c...

The compositions and purity of polycrystalline powder samples of Nd0.7Sr0.3 Mn1-x MgxO3 (x = 0.0, 0.1, 0.2, 0.3), LaCr1-xMnxO3 (x = 0.0, 0.1, 0.2, 0.3) and La1-x Ndx Cr0.5 Mn0.5 O3 (x = 0.0, 0.15, 0.2) were characterized by X-ray diffraction and chemical analysis. The magnetic properties were investigated by neutron powder diffraction technique and magnetization measurement using a SQUID. All t...

C216 also a potent inhibitor of (Zn/Zn)bLAP. This combined approach provided insights on interaction of bLAP with sulphydryl-containing compounds, showing that metal exchange in site 1 modulates binding to these molecules that, depending on metal nature, may result as enzyme substrates or inhibitors. Work supported by FIRB project from Italian board for education.

Following the seminal work of Von Dreele, powder X-ray diffraction studies on proteins are being established as a valuable complementary technique to single-crystal measurements. A wide range of small proteins have been found to give synchrotron powder diffraction profiles where the peak widths are essentially limited only by the instrumental resolution. The rich information contained in these ...