Browsing by Author "Cowieson, NP"

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    Combined pressure and temperature denaturation of ribonuclease A produces alternate denatured states
    (Elsevier, 2016-05-13) Ryan, TM; Xun, Y; Cowieson, NP; Mata, JP; Jackson, AJ; Pauw, BR; Smith, AJ; Kirby, N; McGillivray, DJ
    Protein folding, unfolding and misfolding have become critically important to a range of health and industry applications. Increasing high temperature and high pressure are used to control and speed up reactions. A number of studies have indicated that these parameters can have a large effect on protein structure and function. Here we describe the additive effects of these parameters on the small angle scattering behaviour of ribonuclease A. We find that alternate unfolded structures can be obtained with combined high pressure and temperature treatment of the protein. © 2016 Elsevier Inc.
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    Cortactin adopts a globular conformation and bundles actin into sheets
    (American Society for Biochemistry and Molecular Biology, 2008-06-06) Cowieson, NP; King, GJ; Cookson, DJ; Ross, I; Huber, T; Hume, DA; Kobe, B; Martin, JL
    Cortactin is a filamentous actin-binding protein that plays a pivotal role in translating environmental signals into coordinated rearrangement of the cytoskeleton. The dynamic reorganization of actin in the cytoskeleton drives processes including changes in cell morphology, cell migration, and phagocytosis. In general, structural proteins of the cytoskeleton bind in the N-terminal region of cortactin and regulatory proteins in the C-terminal region. Previous structural studies have reported an extended conformation for cortactin. It is therefore unclear how cortactin facilitates cross-talk between structural proteins and their regulators. In the study presented here, circular dichroism, chemical cross-linking, and small angle x-ray scattering are used to demonstrate that cortactin adopts a globular conformation, thereby bringing distant parts of the molecule into close proximity. In addition, the actin bundling activity of cortactin is characterized, showing that fully polymerized actin filaments are bundled into sheet-like structures. We present a low resolution structure that suggests how the various domains of cortactin interact to coordinate its array of binding partners at sites of actin branching. © 2008, American Society for Biochemistry and Molecular Biology
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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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    Structural ensembles reveal intrinsic disorder for the multi-stimuli responsive bio-mimetic protein rec1-resilin
    (Springer Nature, 2015-06-04) Balu, R; Knott, RB; Cowieson, NP; Elvin, CM; Hill, AJ; Choudhury, NR; Dutta, NK
    Rec1-resilin is the first recombinant resilin-mimetic protein polymer, synthesized from exon-1 of the Drosophila melanogaster gene CG15920 that has demonstrated unusual multi-stimuli responsiveness in aqueous solution. Crosslinked hydrogels of Rec1-resilin have also displayed remarkable mechanical properties including near-perfect rubber-like elasticity. The structural basis of these extraordinary properties is not clearly understood. Here we combine a computational and experimental investigation to examine structural ensembles of Rec1-resilin in aqueous solution. The structure of Rec1-resilin in aqueous solutions is investigated experimentally using circular dichroism (CD) spectroscopy and small angle X-ray scattering (SAXS). Both bench-top and synchrotron SAXS are employed to extract structural data sets of Rec1-resilin and to confirm their validity. Computational approaches have been applied to these experimental data sets in order to extract quantitative information about structural ensembles including radius of gyration, pair-distance distribution function, and the fractal dimension. The present work confirms that Rec1-resilin is an intrinsically disordered protein (IDP) that displays equilibrium structural qualities between those of a structured globular protein and a denatured protein. The ensemble optimization method (EOM) analysis reveals a single conformational population with partial compactness. This work provides new insight into the structural ensembles of Rec1-resilin in solution. © 2017 Macmillan Publishers Limited, part of Springer Nature