The Micro Crystallography beamline (formerly known as the Protein Micro-crystal and Small Molecule X-ray Diffraction beamline) uses multiple wavelength anomalous dispersion (MAD) to determine crystal structures and derive electron density maps. It is ideal for weakly-diffracting, hard-to-crystallise proteins, viruses, protein assemblies and nucleic acids as well as smaller molecules such as inorganic catalysts and organic drug molecules.
Expert technical assistance is available to help users who are not specialist crystallographers.
Features
Finely focused x-ray beam for high-resolution structure determination from extremely small crystals.
Intense beam allows for the determination of single crystal structures of small molecule samples from crystals less than 1 micron in size.
User changeable energy
High resolution single wavelength anomalous dispersion (SAD)
Multiple wavelength anomalous dispersion (MAD) [fully automated via new beam-steering feedback function]
Automated scans of metal edges for MAD and excitation scans
sample mounting robot (SSRL type) for robotic loading and centering of crystals
Optional manual mounting of crystals directly onto gonio
Sensitive Vortex-EX Si-drift fluorescence detector that permits MAD scans on micro-crystals
High-res sample video microscope (coincident with the beam) for alignment of crystals to the x-ray beam embedded in the Blu-Ice User Interface
Full remote access for beamline GUI and robot operation
Shorter wavelength x-rays to minimise absorption
High-performance stereo-microscope for mounting of micro crystals at the beamline
Rapid, automatic data integration and scaling software for real-time processing
To be completed: Kappa goniostat (interchangeable) for full diffraction sphere coverage
Potential to add second end-station designed specifically for small molecules
Applications
High-resolution crystal structures and electron density maps provide essential information for many fields of science, including molecular biology, rational drug design and proteomics.
In addition to providing higher-resolution information to refine preliminary structures from high-throughput methods, the micro-crystallography beamline will enable structure determination for substances that are difficult to obtain in crystalline form, such as receptors.
The intense beam allows for the determination of single crystal structures of small molecule samples from crystals less than 1 micron in size. This allows for structure determination for samples that are otherwise not suitable for single crystal analysis such as powder grains, micro needles and other micro-crystals.
X-ray diffraction is the most widely-used method for protein structure determination, providing information for a wide range of applications, including drug development, food technology, agriculture, manufacturing and chemical processing. Small-molecule structure elucidation via the Micro Crystallography beamline has the potential to support an even wider range of chemical, geochemical, material science and medical research and development activities, particularly those with a research emphasis on very small crystals.
Examples of synchrotron x-ray crystallography applications
determination of the structures of protein complexes, providing valuable information for other synchrotron studies of mechanisms and ligand binding at atomic resolution
structural studies of proteins critical to insect physiology to inform the development of new or improved insecticides
structural studies of transport proteins in plant roots to improve knowledge of salt resistance mechanisms used by native plants and agricultural crops
structural studies of malarial proteins to assist the development of drugs that block malaria parasite entry to red blood cells
structural studies of growth factors to improve understanding of cancer growth and develop better treatments
investigation of the global structures of large biological molecules, to complement information obtained from NMR and other studies, and investigate the regulation of key cellular processes that underpin healthy biological functioning or are implicated in disease states
structural studies of antibodies, to assist the identification of bio-sensor platforms for cancer detection.
determination of the structure of the anthrax lethal factor, making it possible to pursue the development of anti-toxins.
Case study 1: Rational drug design - influenza
The ability of synchrotron x-rays to reveal the detailed structures of biological proteins and their interactions has enabled researchers to develop a new approach to drug discovery. Rational drug design identifies opportunities to block or modify molecular interactions. The anti-influenza drug RelenzaTM is the world’s first structure-based anti-viral drug and an early example of rationally based drug design methodologies. RelenzaTM was developed in the mid-1990s by a CSIRO team led by Peter Coleman and Jose Varghese.
Coleman and Varghese used synchrotron protein crystallography to create a high resolution picture of the neuraminidase protein on the virus surface.
Case study 2: Therapeutics for chronic inflammatory diseases
Chronic inflammatory diseases represent one of the greatest health problems in the developed world, and macrophages play a central role in the inflammation process. Researchers from the University of Queensland are investigating macrophage proteins from mice. They want to develop a better understanding of the inflammation process in arthritis and other chronic inflammatory diseases and to identify targets for the development of new anti-inflammatory therapeutics.
Associate Professor Jenny Martin and her colleagues have established a bacterial expression system to screen hundreds of proteins to identify those that are suitable for structural studies. Proteins that express well in the small-scale bacterial system are then produced in large scale and evaluated further by structural techniques.
User Communities
Currently, there are approximately 20 institutions with regular access to the MX1 and MX2 beamlines at the Australian Synchrotron. Typically, each of these institutions have several groups that shape their user community - these are often spread across medical, biological and chemistry departments. The number of potential users has grown to now encompass groups conducting research in inorganic chemistry and other micro-crystal materials research.
The specialist Protein Crystallography community, from its beginning in the late 1970s, has formed a cohesive and cooperative group with good communications between the chief investigators. The larger institutions and laboratories are centred around the Australian state capitals and Auckland, with a growing number of smaller laboratories elsewhere in both countries. In the not-too-distant past, these laboratories were only able to gain access to synchrotron sources overseas, principally the BioCARS facility at the Advanced Photon Source, near Chicago, through the Australian Synchrotron Research Program (ASRP).
By 2010 it is expected that there will be a much larger community that will include non-specialist protein crystallography users, who would use the beamlines for routine structure determination and view the beamlines as another analytic tool in their armory.
Configuration Modes
In contrast to other beamlines at the Australian Synchrotron, the configurations of the Macro- and Micro Crystallography endstations are largely fixed such that all user groups employ a standardised gonio head and crystal mounts for analysing crystals. Further details on crystal mounts and sample environments are detailed in the Samples webpage for this beamline.
The information below outlines the optical configuration of the Micro Crystallography beamline; from the synchrotron machine wall (‘white’ beam) through to the endstation (single wavelength x-rays onto sample). Further information for beamline users can be obtained in the Technical Information webpage for this beamline.
Photon Delivery: the Machine Wall, Hutch A and Beam Transport Tube
Photo above left: The machine wall (painted white), including machine access door (far right of view), Hutch A painted aquamarine, then white-beam transport tube. Photo above centre: Contents of Hutch A, including water-cooled fixed masks and bremsstrahlung collimator (photo courtesy Sandra Morrow). Photo above right: white-beam transport tube.
Wavelength Selection and Beam Steering/Focusing: the Optics Hutch B
Optics Hutch B above, and hutch contents below.
Photo above left: Rear of view is where white beam enters Hutch B. Components running downstream include white-beam slits and beam positioning systems, then DCM vessel in foreground. Photo above right: DCM vessel (right of view), monochromatic slits and mono-beam positioning systems, then combined VFM/HFM tank (left of view).
Beam Focusing, Sample Environment and Detectors: the Experiment Endstation Hutch C
Endstation (experiment) Hutch C above, and hutch contents below.
Endstation Hutch Detail: beam enters Hutch C from far left. Endstation components include fluorescent screen and beam position monitor, then microfocusing HFM tank partially obscured by the SAM robot dewar (centre left of photo). Centre right of photo shows the sample environment including Cryojet, x-ray fluorescence detector, beamstop and goniometer. Right of photo shows the ADSC Quantum 315r Detector within its support frame.
Beamline Controls and Sample Preparation: the User Cabin
