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99 results on '"Cowieson, Nathan"'

52. Controlling the properties of the micellar and gel phase by varying the counterion in functionalised-dipeptide systems

Author

McAulay, Kate, primary, Ucha, Pedro Agís, additional, Wang, Han, additional, Fuentes-Caparrós, Ana M., additional, Thomson, Lisa, additional, Maklad, Osama, additional, Khunti, Nikul, additional, Cowieson, Nathan, additional, Wallace, Matthew, additional, Cui, Honggang, additional, Poole, Robert J., additional, Seddon, Annela, additional, and Adams, Dave J., additional

Published
2020
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57. Multimodal Control of Liquid Crystalline Mesophases from Surfactants with Photoswitchable Tails

Author

Evans, Rachel, Houston, Judith E, Kelly, Elaine A, Kruteva, Margarita, Chrissopoulou, Kiriaki, Cowieson, Nathan, Evans, Rachel Claire [0000-0003-2956-4857], and Apollo - University of Cambridge Repository

Subjects
3403 Macromolecular and Materials Chemistry, 34 Chemical Sciences, 7 Affordable and Clean Energy, 4016 Materials Engineering, 40 Engineering
Abstract

Non-invasive manipulation of the hierarchical structure of functional materials is a key challenge in the advancement of optoelectronics, energy conversion and storage devices and drug delivery systems. Here, using a combination of small-angle X-ray scattering and polarised optical microscopy, we decipher the various structure/self- assembly relationships of neutral surfactants bearing photoswitchable tails, which self-organise into a rich variety of lyotropic liquid crystalline mesophases. Facile, multimodal control of the nanoscale morphology of these single-component systems is achieved through: i) molecular structure, via careful selection of the alkyl tail/ethylene oxide headgroup lengths; ii) concentration; iii) temperature; and iv) photoisomerisation. The nanoscale architectures range from the weakly concentrated hyperswollen lamellar phases, the more common lyotropic lamellar and hexagonal phases, to pure thermotropic liquid crystals; all of which are accessible at room temperature. Photoisomerisation with UV light leads to the reversible destruction of the liquid crystalline phase, which can be spatially controlled through the use of a mask. This extensive study demonstrates the versatility of neutral photosurfactants and paves the way for them to be investigated for new applications, such as photoresponsive templates or drug delivery systems.

Published
2019
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59. MX2: a high-flux undulator microfocus beamline serving both the chemical and macromolecular crystallography communities at the Australian Synchrotron

Author

Aragão, David, primary, Aishima, Jun, additional, Cherukuvada, Hima, additional, Clarken, Robert, additional, Clift, Mark, additional, Cowieson, Nathan Philip, additional, Ericsson, Daniel Jesper, additional, Gee, Christine L., additional, Macedo, Sofia, additional, Mudie, Nathan, additional, Panjikar, Santosh, additional, Price, Jason Roy, additional, Riboldi-Tunnicliffe, Alan, additional, Rostan, Robert, additional, Williamson, Rachel, additional, and Caradoc-Davies, Thomas Tudor, additional

Published
2018
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69. MX1: a bending-magnet crystallography beamline serving both chemical and macromolecular crystallography communities at the Australian Synchrotron

Author

Cowieson, Nathan Philip, primary, Aragao, David, additional, Clift, Mark, additional, Ericsson, Daniel J., additional, Gee, Christine, additional, Harrop, Stephen J., additional, Mudie, Nathan, additional, Panjikar, Santosh, additional, Price, Jason R., additional, Riboldi-Tunnicliffe, Alan, additional, Williamson, Rachel, additional, and Caradoc-Davies, Tom, additional

Published
2015
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74. Structural Basis for Regulation of the Human Acetyl-CoA Thioesterase 12 and Interactions with the Steroidogenic Acute Regulatory Protein-related Lipid Transfer (START) Domain

Author

Swarbrick, Crystall M.D., primary, Roman, Noelia, additional, Cowieson, Nathan, additional, Patterson, Edward I., additional, Nanson, Jeffrey, additional, Siponen, Marina I., additional, Berglund, Helena, additional, Lehtiö, Lari, additional, and Forwood, Jade K., additional

Published
2014
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77. Dimerization of Plant Defensin NaD1 Enhances Its Antifungal Activity

Author

Lay, Fung T., primary, Mills, Grant D., additional, Poon, Ivan K.H., additional, Cowieson, Nathan P., additional, Kirby, Nigel, additional, Baxter, Amy A., additional, van der Weerden, Nicole L., additional, Dogovski, Con, additional, Perugini, Matthew A., additional, Anderson, Marilyn A., additional, Kvansakul, Marc, additional, and Hulett, Mark D., additional

Published
2012
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78. The X-ray Crystal Structure of Full-Length Human Plasminogen

Author

Law, Ruby H.P., primary, Caradoc-Davies, Tom, additional, Cowieson, Nathan, additional, Horvath, Anita J., additional, Quek, Adam J., additional, Encarnacao, Joanna Amarante, additional, Steer, David, additional, Cowan, Angus, additional, Zhang, Qingwei, additional, Lu, Bernadine G.C., additional, Pike, Robert N., additional, Smith, A. Ian, additional, Coughlin, Paul B., additional, and Whisstock, James C., additional

Published
2012
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83. Cloning, expression, purification and characterization of a DsbA-like protein from Wolbachia pipientis

Author

Kurz, Mareike, primary, Iturbe-Ormaetxe, Iñaki, additional, Jarrott, Russell, additional, Cowieson, Nathan, additional, Robin, Gautier, additional, Jones, Alun, additional, King, Gordon J., additional, Frei, Patrick, additional, Glockshuber, Rudi, additional, O’Neill, Scott L., additional, Heras, Begoña, additional, and Martin, Jennifer L., additional

Published
2008
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90. An Inflammatory Role for the Mammalian Carboxypeptidase Inhibitor Latexin: Relationship to Cystatins and the Tumor Suppressor TIG1

Author

Aagaard, Anna, primary, Listwan, Pawel, additional, Cowieson, Nathan, additional, Huber, Thomas, additional, Ravasi, Timothy, additional, Wells, Christine A., additional, Flanagan, Jack U., additional, Kellie, Stuart, additional, Hume, David A., additional, Kobe, Bostjan, additional, and Martin, Jennifer L., additional

Published
2005
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92. Structure and activity of exo-1,3/1,4-β-glucanase from marine bacterium Pseudoalteromonas sp. BB1 showing a novel C-terminal domain.

Author

Nakatani, Yoshio, Cutfield, Susan M., Cowieson, Nathan P., and Cutfield, John F.

Subjects
GLYCOSIDASES, CRYSTAL structure, MARINE algae, X-ray scattering, CARBOHYDRATES, PROTEIN structure
Abstract

Following the discovery of an exo-1,3/1,4-β-glucanase (glycoside hydrolase family 3) from a seaweed-associated bacterium Pseudoalteromonas sp. BB1, the recombinant three-domain protein (ExoP) was crystallized and its structure solved to 2.3 Å resolution. The first two domains of ExoP, both of which contribute to the architecture of the active site, are similar to those of the two-domain barley homologue β- d-glucan exohydrolase (ExoI) with a distinctive Trp-Trp clamp at the +1 subsite, although ExoI displays broader specificity towards β-glycosidic linkages. Notably, excision of the third domain of ExoP results in an inactive enzyme. Domain 3 has a β-sandwich structure and was shown by CD to be more temperature stable than the native enzyme. It makes relatively few contacts to domain 1 and none at all to domain 2. Two of the domain 3 residues involved at the interface, Q683 (forming one hydrogen bond) and Q676 (forming two hydrogen bonds) were mutated to alanine. Variant Q676A retained about half the activity of native ExoP, but the Q683A variant was severely attenuated. The crystal structure of Q683A-ExoP indicated that domain 3 was highly mobile and that Q683 is critical to the stabilization of ExoP by domain 3. Small-angle X-ray scattering data lent support to this proposal. Domain 3 does not appear to be an obvious carbohydrate-binding domain and is related neither in sequence nor structure to the additional domains characterized in other glycoside hydrolase 3 subgroups. Its major role appears to be for protein stability but it may also help orient substrate. Database Structural data are available in the Protein Data Bank under the accession numbers , , and [ABSTRACT FROM AUTHOR]

Published
2012
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94. The structural basis for autonomous dimerization of the pre-T-cell antigen receptor.

Author

Siew Siew Pang, Berry, Richard, Zhenjun Chen, Lars Kjer-Nielsen, Matthew A. Perugini, King, Glenn F., Christina Wang, Sock Hui Chew, La Gruta, Nicole L., Williams, Neal K., Beddoe, Travis, Tiganis, Tony, Cowieson, Nathan P., Godfrey, Dale I., Purcell, Anthony W., Wilce, Matthew C. J., McCluskey, James, and Rossjohn, Jamie

Subjects
T-cell receptor genes, CELL membranes, IMMUNOGLOBULINS, B cells, ANTIGENS, GENE expression
Abstract

The pre-T-cell antigen receptor (pre-TCR), expressed by immature thymocytes, has a pivotal role in early T-cell development, including TCR β-selection, survival and proliferation of CD4−CD8− double-negative thymocytes, and subsequent αβ T-cell lineage differentiation. Whereas αβTCR ligation by the peptide-loaded major histocompatibility complex initiates T-cell signalling, pre-TCR-induced signalling occurs by means of a ligand-independent dimerization event. The pre-TCR comprises an invariant α-chain (pre-Tα) that pairs with any TCR β-chain (TCRβ) following successful TCR β-gene rearrangement. Here we provide the basis of pre-Tα-TCRβ assembly and pre-TCR dimerization. The pre-Tα chain comprised a single immunoglobulin-like domain that is structurally distinct from the constant (C) domain of the TCR α-chain; nevertheless, the mode of association between pre-Tα and TCRβ mirrored that mediated by the Cα-Cβ domains of the αβTCR. The pre-TCR had a propensity to dimerize in solution, and the molecular envelope of the pre-TCR dimer correlated well with the observed head-to-tail pre-TCR dimer. This mode of pre-TCR dimerization enabled the pre-Tα domain to interact with the variable (V) β domain through residues that are highly conserved across the Vβ and joining (J) β gene families, thus mimicking the interactions at the core of the αβTCR's Vα-Vβ interface. Disruption of this pre-Tα-Vβ dimer interface abrogated pre-TCR dimerization in solution and impaired pre-TCR expression on the cell surface. Accordingly, we provide a mechanism of pre-TCR self-association that allows the pre-Tα chain to simultaneously 'sample' the correct folding of both the V and C domains of any TCR β-chain, regardless of its ultimate specificity, which represents a critical checkpoint in T-cell development. This unusual dual-chaperone-like sensing function of pre-Tα represents a unique mechanism in nature whereby developmental quality control regulates the expression and signalling of an integral membrane receptor complex. [ABSTRACT FROM AUTHOR]

Published
2010
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95. Evaluating protein:protein complex formation using synchrotron radiation circular dichroism spectroscopy.

Author

Cowieson, Nathan P., Miles, Andrew J., Robin, Gautier, Forwood, Jade K., Kobe, Bostjan, Martin, Jennifer L., and Wallace, B. A.

Abstract

Circular dichroism (CD) spectroscopy beamlines at synchrotrons produce dramatically higher light flux than conventional CD instruments. This property of synchrotron radiation circular dichroism (SRCD) results in improved signal-to-noise ratios and allows data collection to lower wavelengths, characteristics that have led to the development of novel SRCD applications. Here we describe the use of SRCD to study protein complex formation, specifically evaluating the complex formed between carboxypeptidase A and its protein inhibitor latexin. Crystal structure analyses of this complex and the individual proteins reveal only minor changes in secondary structure of either protein upon complex formation (i.e., it involves only rigid body interactions). Conventional CD spectroscopy reports on changes in secondary structure and would therefore not be expected to be sensitive to such interactions. However, in this study we have shown that SRCD can identify differences in the vacuum ultraviolet CD spectra that are significant and attributable to complex formation. Proteins 2008. © 2007 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Published
2008
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97. Structural ensembles reveal intrinsic disorder for the multi-stimuli responsive bio-mimetic protein Rec1-resilin

Author

Christopher M. Elvin, Robert Knott, Anita J. Hill, Nathan Cowieson, Rajkamal Balu, Namita Roy Choudhury, Naba K. Dutta, Balu, Rajkamal, Knott, Robert, Cowieson, Nathan P, Elvin, Christopher M, Hill, Anita J, Choudhury, Namita R, and Dutta, Naba K

Subjects
Circular dichroism, Materials science, Protein Conformation, Globular protein, diagnosis, Population, Fractal dimension, Protein Structure, Secondary, Article, Protein structure, X-Ray Diffraction, Scattering, Small Angle, diagnostics, education, chemistry.chemical_classification, education.field_of_study, Multidisciplinary, biology, Small-angle X-ray scattering, bioinspired materials, Circular Dichroism, self-assembly, chemistry, Chemical physics, Radius of gyration, biology.protein, Insect Proteins, Resilin
Abstract

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.

Published
2015

98. Structural characterization of Staphylococcus aureus biotin protein ligase and interaction partners: An antibiotic target

Author

Pendini, Nicole R, Yap, Min Y, Polyak, Steven W, Cowieson, Nathan P, Abell, Andrew, Booker, Grant W, Wallace, John C, Wilce, Jacqueline A, and Wilce, Matthew CJ

Subjects
DNA-binding, bacterial enzyme, small-angle X-ray scattering, biotin-carboxyl carrier protein, biotin protein ligase, biotinylation
Abstract

The essential metabolic enzyme biotin protein ligase (BPL) is a potential target for the development of new antibiotics required to combat drug-resistant pathogens. Staphylococcus aureus BPL (SaBPL) is a bifunctional protein, possessing both biotin ligase and transcription repressor activities. This positions BPL as a key regulator of several important metabolic pathways. Here, we report the structural analysis of both holo- and apo-forms of SaBPL using X-ray crystallography. We also present small-angle X-ray scattering data of SaBPL in complex with its biotin-carboxyl carrier protein substrate as well as the SaBPL:DNA complex that underlies repression. This has revealed the molecular basis of ligand (biotinyl-50-AMP) binding and conformational changes associated with catalysis and repressor function. These data provide new information to better understand the bifunctional activities of SaBPL and to inform future strategies for antibiotic discovery. Refereed/Peer-reviewed

Published
2013

99. Understanding X-ray-induced isomerisation in photoswitchable surfactant assemblies.

Author

Jones BE, Blayo C, Greenfield JL, Fuchter MJ, Cowieson N, and Evans RC

Abstract

Dynamic, responsive materials can be built using photosurfactants (PS) that self-assemble into ordered nanostructures, such as micelles or liquid crystals. These PS contain photoswitchable groups, such as azobenzene (Azo) or, more recently, arylazopyrazoles (AAPs), which change shape and polarity on photoisomerisation between the E and Z states, thus changing the self-assembled structure. Small-angle X-ray scattering (SAXS) is a powerful technique to probe the morphology of PS and can be used to measure the mechanisms of structural changes using in-situ light irradiation with rapid, time-resolved data collection. However, X-ray irradiation has been shown previously to induce Z- to -E isomerisation of Azo-PS, which can lead to inaccuracies in the measured photostationary state. Here, we investigate the effect of light and X-ray irradiation on micelles formed from two different PS, containing either an Azo or AAP photoswitch using SAXS with in-situ light irradiation. The effect of X-ray irradiation on the Z isomer is shown to depend on the photoswitch, solvent, concentration and morphology. We use this to create guidelines for future X-ray experiments using photoswitchable molecules, which can aid more accurate understanding of these materials for application in solar energy storage, catalysis or controlled drug delivery., (Copyright © 2024, Jones et al.)

Published
2024
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