Browsing by Author "Caradoc-Davies, TT"

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    Chemical crystallography at the Australian Synchrotron MX Beamlines
    (SCANZ, 2017-12-03) Price, JR; Aishima, J; Aragao, D; Eriksson, D; Panjikar, S; Riboldi-Tunnicliffe, A; Williamson, R; Caradoc-Davies, TT
    The macromolecular (MX) beamlines at the Australian synchrotron are mixed use between the structural biology and chemical crystallography (CX) communities. Since commissioning the high throughput MX1 bending magnet and the MX2 microfocus undulator beamlines have proven very successful for both communities. The deployment of a 16M Eiger detector (funded by Australian Structural Biology laboratories and Australian Cancer Research Foundation) has changed the ‘standard’ MX2 collection for CX from 1° oscillation in 1 second over 360°, which takes ~15 min with the beam attenuated to give a balance of resolution vs detector overloads to a new shutter less 360° oscillation yielding 3600 frames in 36 sec. This increase in data volume and experiment turnaround time has led to a number of challenges for the workflow for the users and highlighted the biggest dead time for beam is now: search and secure for hand mounting, and robot sample change time for automated sample handling including remote use. Indicative use of MX2 from completed search and secure in a 24-hour experiment with hand mounting (preferred by CX) was 188 completed searches. Maximum robot-mounted samples over the same duration is 288. There is a robot upgrade under development to take sample change times from ~4 min to ~30 sec, and it is anticipated that MX1 will also receive a detector upgrade. This increase in throughput is having a significant impact on our ability to return analysis on the experiment in real time, as well as deliver auto-processed data in a timely fashion (new computational hardware is on its way). Given these dramatic increases in experimental throughput, what are the addition opportunities that may be embraced by the crystallographic community in Australia? What is the future for chemical crystallography at the MX beamlines? A review of the current developments that are underway and some discussion of what may lie in the future will be presented.
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    Crystal structure of posnjakite formed in the first crystal water-cooling line of the ANSTO Melbourne Australian Synchrotron MX1 Double Crystal Monochromator
    (International Union of Crystallography (IUCr), 2020-06-30T14:00:00Z) Mills, SJ; Aishima, J; Aragao, D; Caradoc-Davies, TT; Cowieson, NP; Gee, CL; Ericsson, D; Harrop, SJ; Panjikar, S; Smith, KML; Riboldi-Tunnicliffe, A; Williamson, R; Price, JR
    Exceptionally large crystals of posnjakite, CuSO(OH)(HO), formed during corrosion of a Swagelock(tm) Snubber copper gasket within the MX1 beamline at the ANSTO-Melbourne, Australian Synchrotron. The crystal structure was solved using synchrotron radiation to = 0.029 and revealed a structure based upon [Cu(OH)(HO)O] sheets, which contain Jahn-Teller-distorted Cu octa-hedra. The sulfate tetra-hedra are bonded to one side of the sheet corner sharing and linked to successive sheets extensive hydrogen bonds. The sulfate tetra-hedra are split and rotated, which enables additional hydrogen bonds. © Mills et al. 2020.
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    Establishing micro electron diffraction as new tool for structural biology
    (Society of Crystallographers in Australia and New Zealand, 2017-12-03) Lupton, C; Buijsse, B; Yu, L; Law, R; Radjainia, M; Ramm, G; Caradoc-Davies, TT; Whisstock, J
    X-ray crystallography has been the dominant method for protein structure determination since the first structure of myoglobin was solved in the 1950s. The requirement for large, well-formed, micron-sized crystals can be a limiting factor in obtaining these structures. Consequently, projects that fail to meet these requirements often rely on X-ray Free Electron Lasers (XFELs), a method that require copious amounts of small crystals which is something that cannot be readily achieved for many proteins. In addition, access to free-electron lasers is prohibitive with only a handful currently operating. Given these challenges, an alternative method is required to determine high-resolution protein structures from small crystals. Recent advances in cryo electron microscopy have allowed for the development of a technique called micro electron diffraction (MED) where an electron microscope is used to collect electron diffraction patterns from cryogenically frozen sub-micron (< 500 nm) sized crystals. This technique is becoming increasingly popular with several structures solved including the core peptide of Tau filaments to a resolution of 1.1Å, the first novel structure solved by MED. Additionally, numerous crystallisation conditions that are typically overlooked for use by conventional methods have been shown to contain nano-crystals when analysed by electron microscopy, presenting new opportunities for MED. In collaboration with Thermo Fisher (formerly FEI), we are working to establish MED as a viable alternative to both X-ray crystallography and XFELs for protein structure determination here at Monash University. Preliminary data collection techniques have been developed, along with preprocessing software to help streamline indexing, merging, and analysis of electron diffraction data. More recently, we have successfully collected test datasets of lysozyme that have yielded structures with a resolution of 2.8Å. Together, we have demonstrated the feasibility of this technique and now look toward applying it to novel protein samples.
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    Recent and future developments on the Australian Synchrotron MX2 beamline driven by the Eiger 16M detector deployment
    (Society of Crystallographers in Australia and New Zealand, 2017-12-03) Aragao, D; Aishima, J; Clarken, R; Eriksson, D; Macedo, S; Moll, A; Mudie, N; Panjikar, S; Price, JR; Riboldi-Tunnicliffe, A; Williamson, R; Caradoc-Davies, TT
    The new pixel array detector — Eiger 16M — deployed on MX2 in February 2017 has now generated more than 152 Tb of data compared with 18 Tb in the same period last year using a CCD based detector. This has not only revolutionised the speed that datasets are collected but also put challenges in the way we collect, take notes, process and store data. Here we will present how some of these challenges have been tackled and what are the future developments already being worked on for deployment in the next 12 months. We will also briefly describe one of the most common traps on collecting data on the Eiger 16M.