Structure determination for small and large molecules

Powder X-ray diffraction for research and industryCollapse AllThe Braggs crystallography facility overview

Single-crystal X-ray structure determination provides the single most important means of unambiguously characterising molecules in the solid state.

Using this technique an experimenter can determine the exact 3-D arrangement of atoms in a structure - this includes the relative positions, bonding and interactions of all atoms in a structure. No single step can provide more information about the way a biological/chemical agent works than its three dimensional structure.

Powder X-ray diffraction (PXRD) is a powerful technique enabling rapid, non-destructive analysis of compounds and multi-component mixtures with simple sample preparation. Quick identification of unknown materials and materials characterisation in a range of fields, such as metallurgy, mineralogy, forensic science, archaeology, and pharmaceutical sciences, are possible.

Applications include phase identification, quantification of crystallinity, determination of lattice parameters, evaluation of thermal expansion and phase transitions.

The facility

The main capabilities of the Bragg Crystallography Facility include:

High throughput small molecule structure determination

Protein and macromolecule structure determination

Screening of large protein samples for subsequent synchrotron data collection

Powder diffraction analysis

High-throughput analysis ideal for mineral samples, clays and soils

More detailed analysis (thermal, pressure studies)

Key equipment includes two state-of- the-art single-crystal diffractometers:

a Mo-target Oxford Diffraction X-Calibur X-ray diffractometer for small molecule structure determination

a Cu-target Rigaku Hiflux Homelab rotating anode X-ray diffractometer for large molecule structure determination

And two powder X-ray diffractometers:

a Co-target Bruker D4 Endeavour powder diffractometer

a Cu-target Bruker D8 Advance powder diffractometer with variable temperature and pressure capabilities (Co and Cr tubes can be installed by negotiation)

Commercial applications

1. High throughput small molecule structure determination (SMX)

SMX is used to determine the structures or inorganic, organic and mineralogical species (i.e. compounds with a few atoms to those containing a thousand atoms) and to define the absolute structure and configuration of chiral (asymmetric) compounds. SMX can be used to identify and characterise potential drug leads, protein inhibitors/activators and nanoscale/catalytic homogenous systems.

2. Protein and macromolecule structure determination (PX)

PX structure determination offers industries with a research focus in biotechnology, (stem) cell biology, biochemistry, biomedicine and biotechnology single step access to the 3-D structure of a protein or enzyme. This information can be used to further understand drug targets or biological activity, for example. Our PX capable instrument can also be used for other macromolecular structure determination, e.g. polynucleic acids, polymers and supramolecular extended network materials. The services provided under items 1 and 2 can include:

Selection and mounting of crystal specimens

X-ray data collection

Digital movies of crystals

Face-indexed numerical absorption corrections (when needed)

Structure solution and refinement

Full crystallographic report with experimental details, figures, files, and tables of crystallographic data

3. Screening of weakly diffracting protein samples prior to synchrotron access

Samples that require more intense X-ray sources due to inherently weak X-ray diffraction using conventional sources can only be structurally determined using the intense X-ray beams provided by a synchrotron. Examples of these samples include membrane bound proteins and biomacromolecules with dimensions greater than 60 x 10-10m.

The Bragg Crystallography Facility will be able to screen samples locally, thereby allowing more sensitive species to be screened for the first time and providing a rapid screening facility for other weakly diffracting samples.

4. Powder X-ray Diffraction

Different access models exist for the PXRD equipment. Please contact Assoc. Prof. Chris Sumby for further details.

Powder samples can be run on the:

Bruker D4 Endeavour powder diffractometer in a high-throughput mode. Multiple samples can be loaded (up to 66 in one run) and run by trained users or as a service. The samples are mounted on flat plates.

Established users can access the Bruker D8 Advance powder diffractometer to run samples in capillaries, on flat plates or within the Anton Parr furnace. Variable temperature capillary work may be possible in the future.