1
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Quek AJ, Cowieson NP, Caradoc-Davies TT, Conroy PJ, Whisstock JC, Law RHP. A High-Throughput Small-Angle X-ray Scattering Assay to Determine the Conformational Change of Plasminogen. Int J Mol Sci 2023; 24:14258. [PMID: 37762561 PMCID: PMC10531915 DOI: 10.3390/ijms241814258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 09/09/2023] [Accepted: 09/11/2023] [Indexed: 09/29/2023] Open
Abstract
Plasminogen (Plg) is the inactive form of plasmin (Plm) that exists in two major glycoforms, referred to as glycoforms I and II (GI and GII). In the circulation, Plg assumes an activation-resistant "closed" conformation via interdomain interactions and is mediated by the lysine binding site (LBS) on the kringle (KR) domains. These inter-domain interactions can be readily disrupted when Plg binds to lysine/arginine residues on protein targets or free L-lysine and analogues. This causes Plg to convert into an "open" form, which is crucial for activation by host activators. In this study, we investigated how various ligands affect the kinetics of Plg conformational change using small-angle X-ray scattering (SAXS). We began by examining the open and closed conformations of Plg using size-exclusion chromatography (SEC) coupled with SAXS. Next, we developed a high-throughput (HTP) 96-well SAXS assay to study the conformational change of Plg. This method enables us to determine the Kopen value, which is used to directly compare the effect of different ligands on Plg conformation. Based on our analysis using Plg GII, we have found that the Kopen of ε-aminocaproic acid (EACA) is approximately three times greater than that of tranexamic acid (TXA), which is widely recognized as a highly effective ligand. We demonstrated further that Plg undergoes a conformational change when it binds to the C-terminal peptides of the inhibitor α2-antiplasmin (α2AP) and receptor Plg-RKT. Our findings suggest that in addition to the C-terminal lysine, internal lysine(s) are also necessary for the formation of open Plg. Finally, we compared the conformational changes of Plg GI and GII directly and found that the closed form of GI, which has an N-linked glycosylation, is less stable. To summarize, we have successfully determined the response of Plg to various ligand/receptor peptides by directly measuring the kinetics of its conformational changes.
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Affiliation(s)
- Adam J. Quek
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Nathan P. Cowieson
- Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK
| | - Tom T. Caradoc-Davies
- Australian Synchrotron, ANSTO_Melbourne, 800 Blackburn Rd., Clayton, VIC 3168, Australia
| | - Paul J. Conroy
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, VIC 3800, Australia
| | - James C. Whisstock
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Ruby H. P. Law
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, VIC 3800, Australia
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2
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Blayo C, Kelly EA, Houston JE, Khunti N, Cowieson NP, Evans RC. Light-responsive self-assembly of a cationic azobenzene surfactant at high concentration. Soft Matter 2020; 16:9183-9187. [PMID: 33001130 DOI: 10.1039/d0sm01512a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The formation of high-concentration mesophases by a cationic azobenzene photosurfactant is described for the first time. Using a combination of polarised optical microscopy and small-angle X-ray scattering, optically anisotropic, self-assembled structures with long-range order are reported. The mesophases are disrupted or lost upon UV irradiation.
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Affiliation(s)
- Camille Blayo
- School of Chemistry, Trinity College Dublin, College Green, Dublin 2, Ireland
| | - Elaine A Kelly
- Department of Materials Science and Metallurgy, 27 Charles Babbage Road, CB3 0FS Cambridge, UK.
| | - Judith E Houston
- European Spallation Source (ESS), Odarslövsvägen 113, 22592 Lund, Sweden
| | - Nikul Khunti
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - Nathan P Cowieson
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - Rachel C Evans
- Department of Materials Science and Metallurgy, 27 Charles Babbage Road, CB3 0FS Cambridge, UK.
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3
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Cowieson NP, Edwards-Gayle CJC, Inoue K, Khunti NS, Doutch J, Williams E, Daniels S, Preece G, Krumpa NA, Sutter JP, Tully MD, Terrill NJ, Rambo RP. Beamline B21: high-throughput small-angle X-ray scattering at Diamond Light Source. J Synchrotron Radiat 2020; 27:1438-1446. [PMID: 32876621 PMCID: PMC7467336 DOI: 10.1107/s1600577520009960] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 07/20/2020] [Indexed: 05/06/2023]
Abstract
B21 is a small-angle X-ray scattering (SAXS) beamline with a bending magnet source in the 3 GeV storage ring at the Diamond Light Source Ltd synchrotron in the UK. The beamline utilizes a double multi-layer monochromator and a toroidal focusing optic to deliver 2 × 1012 photons per second to a 34 × 40 µm (FWHM) focal spot at the in-vacuum Eiger 4M (Dectris) detector. A high-performance liquid chromatography system and a liquid-handling robot make it possible to load solution samples into a temperature-controlled in-vacuum sample cell with a high level of automation. Alternatively, a range of viscous or solid materials may be loaded manually using a range of custom sample cells. A default scattering vector range from 0.0026 to 0.34 Å-1 and low instrument background make B21 convenient for measuring a wide range of biological macromolecules. The beamline has run a full user programme since 2013.
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Affiliation(s)
- Nathan P. Cowieson
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | | | - Katsuaki Inoue
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Nikul S. Khunti
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - James Doutch
- ISIS Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Eugene Williams
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Steven Daniels
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Geoff Preece
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Nicholas A. Krumpa
- Projects and Mechanical Engineering Group, Science and Technology Facilities Council, Daresbury Laboratory, Warrington, Cheshire WA4 4AD, United Kingdom
| | - John P. Sutter
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Mark D. Tully
- BM29 BIOSAXS, European Synchroton Radiation Facility, 71 avenue des Martyrs, Grenoble, Isère 38043, France
| | - Nick J. Terrill
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Robert P. Rambo
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
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4
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Riley BT, Broendum SS, Reboul CF, Cowieson NP, Costa MGS, Kass I, Jackson C, Perahia D, Buckle AM, McGowan S. Dynamic Motion and Communication in the Streptococcal C1 Phage Lysin, PlyC. PLoS One 2015; 10:e0140219. [PMID: 26470022 PMCID: PMC4607406 DOI: 10.1371/journal.pone.0140219] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 09/23/2015] [Indexed: 11/26/2022] Open
Abstract
The growing problem of antibiotic resistance underlies the critical need to develop new treatments to prevent and control resistant bacterial infection. Exogenous application of bacteriophage lysins results in rapid and specific destruction of Gram-positive bacteria and therefore lysins represent novel antibacterial agents. The PlyC phage lysin is the most potent lysin characterized to date and can rapidly lyse Group A, C and E streptococci. Previously, we have determined the X-ray crystal structure of PlyC, revealing a complicated and unique arrangement of nine proteins. The scaffold features a multimeric cell-wall docking assembly bound to two catalytic domains that communicate and work synergistically. However, the crystal structure appeared to be auto-inhibited and raised important questions as to the mechanism underlying its extreme potency. Here we use small angle X-ray scattering (SAXS) and reveal that the conformational ensemble of PlyC in solution is different to that in the crystal structure. We also investigated the flexibility of the enzyme using both normal mode (NM) analysis and molecular dynamics (MD) simulations. Consistent with our SAXS data, MD simulations show rotational dynamics of both catalytic domains, and implicate inter-domain communication in achieving a substrate-ready conformation required for enzyme function. Our studies therefore provide insights into how the domains in the PlyC holoenzyme may act together to achieve its extraordinary potency.
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Affiliation(s)
- Blake T. Riley
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - Sebastian S. Broendum
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - Cyril F. Reboul
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
- Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Australia
| | | | - Mauricio G. S. Costa
- Programa de Computação Científica, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Itamar Kass
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
- Victorian Life Sciences Computation Initiative Life Sciences Computation Centre, Monash University, Clayton, Australia
| | - Colin Jackson
- Research School of Chemistry, Australian National University, Canberra, Australia
| | - David Perahia
- Laboratoire de Biologie et de Pharmacologie Appliquée, Ecole Normale Supérieure de Cachan, Centre National de la Recherche Scientifique, Cachan, France
| | - Ashley M. Buckle
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
- * E-mail: (AMB); (SM)
| | - Sheena McGowan
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia
- * E-mail: (AMB); (SM)
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5
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Balu R, Knott R, Cowieson NP, Elvin CM, Hill AJ, Choudhury NR, Dutta NK. Structural ensembles reveal intrinsic disorder for the multi-stimuli responsive bio-mimetic protein Rec1-resilin. Sci Rep 2015; 5:10896. [PMID: 26042819 PMCID: PMC4455251 DOI: 10.1038/srep10896] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 04/21/2015] [Indexed: 01/08/2023] Open
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.
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Affiliation(s)
- Rajkamal Balu
- Ian Wark Research Institute, University of South Australia, Mawson Lakes campus, Mawson lakes, South Australia 5095, Australia
| | - Robert Knott
- ANSTO, Private Mail Bag, Kirrawee, New South Wales 2232, Australia
| | - Nathan P. Cowieson
- Centre for Synchrotron Science, Monash University, Victoria 3800, Australia
| | - Christopher M. Elvin
- CSIRO Agriculture, Level 6, Queensland Bioscience Precinct, St Lucia, Queensland 4067, Australia
| | - Anita J. Hill
- CSIRO Manufacturing, Clayton, Victoria 3168, Australia
| | - Namita R. Choudhury
- Ian Wark Research Institute, University of South Australia, Mawson Lakes campus, Mawson lakes, South Australia 5095, Australia
| | - Naba K. Dutta
- Ian Wark Research Institute, University of South Australia, Mawson Lakes campus, Mawson lakes, South Australia 5095, Australia
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6
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Kirby NM, Cowieson NP. Time-resolved studies of dynamic biomolecules using small angle X-ray scattering. Curr Opin Struct Biol 2014; 28:41-6. [PMID: 25108308 DOI: 10.1016/j.sbi.2014.07.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 07/10/2014] [Accepted: 07/18/2014] [Indexed: 12/30/2022]
Abstract
Small angle X-ray scattering (SAXS) of biomacromolecules in solution has become a prominent technique in structural biology. Whilst the majority of current use is for static measurements, the field is also advancing for measurements where the sample at the beam position changes with time, using high throughput systems, chromatography, high speed mixing and pump-probe techniques in particular. Time resolved work is greatly aided by increasingly sophisticated software for acquiring and analysing data, together with developments in X-ray sources, beamline optics and detectors. The exploitation of spatial coherence is under development, with X-ray free electron lasers aiming to provide major advances in single molecule structure reconstruction and time resolution. Here we provide an overview of current developments advancing time resolved solution SAXS.
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Affiliation(s)
- Nigel M Kirby
- Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia.
| | - Nathan P Cowieson
- Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia
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7
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Murat P, Zhong J, Lekieffre L, Cowieson NP, Clancy JL, Preiss T, Balasubramanian S, Khanna R, Tellam J. G-quadruplexes regulate Epstein-Barr virus-encoded nuclear antigen 1 mRNA translation. Nat Chem Biol 2014; 10:358-64. [PMID: 24633353 PMCID: PMC4188979 DOI: 10.1038/nchembio.1479] [Citation(s) in RCA: 194] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 02/14/2014] [Indexed: 01/29/2023]
Abstract
Viruses that establish latent infections have evolved unique mechanisms to avoid host immune recognition. Maintenance proteins of these viruses regulate their synthesis to levels sufficient for maintaining persistent infection but below threshold levels for host immune detection. The mechanisms governing this finely tuned regulation of viral latency are unknown. Here we show that mRNAs encoding gammaherpesviral maintenance proteins contain within their open reading frames clusters of unusual structural elements, G-quadruplexes, which are responsible for the cis-acting regulation of viral mRNA translation. By studying the Epstein-Barr virus-encoded nuclear antigen 1 (EBNA1) mRNA, we demonstrate that destabilization of G-quadruplexes using antisense oligonucleotides increases EBNA1 mRNA translation. In contrast, pretreatment with a G-quadruplex-stabilizing small molecule, pyridostatin, decreases EBNA1 synthesis, highlighting the importance of G-quadruplexes within virally encoded transcripts as unique regulatory signals for translational control and immune evasion. Furthermore, these findings suggest alternative therapeutic strategies focused on targeting RNA structure within viral ORFs.
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Affiliation(s)
- Pierre Murat
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Jie Zhong
- Tumour Immunology, Department of Immunology, Clive Berghofer Cancer Research Centre, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
- QIMR Centre for Immunotherapy and Vaccine Development, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Lea Lekieffre
- Tumour Immunology, Department of Immunology, Clive Berghofer Cancer Research Centre, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
- QIMR Centre for Immunotherapy and Vaccine Development, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Nathan P Cowieson
- Centre for Synchrotron Science, Monash University, Melbourne, Victoria, Australia
| | - Jennifer L Clancy
- Genome Biology Department, The John Curtin School of Medical Research, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Thomas Preiss
- Genome Biology Department, The John Curtin School of Medical Research, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Shankar Balasubramanian
- Department of Chemistry, University of Cambridge, Cambridge, UK
- Cambridge Institute, Cancer Research UK, Li Ka Shing Center, Cambridge, UK
- School of Clinical Medicine, The University of Cambridge, Addenbrooke’s Hospital, Hills Road, Cambridge, UK
| | - Rajiv Khanna
- Tumour Immunology, Department of Immunology, Clive Berghofer Cancer Research Centre, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
- QIMR Centre for Immunotherapy and Vaccine Development, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Judy Tellam
- Tumour Immunology, Department of Immunology, Clive Berghofer Cancer Research Centre, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
- QIMR Centre for Immunotherapy and Vaccine Development, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
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8
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Pendini NR, Yap MY, Polyak SW, Cowieson NP, Abell A, Booker GW, Wallace JC, Wilce JA, Wilce MCJ. Structural characterisation of Staphylococcus aureus
biotin protein ligase and interaction partners: An antibiotic target. Protein Sci 2013. [DOI: 10.1002/pro.2399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Nicole R. Pendini
- Department of Biochemistry and Molecular Biology; School of Biomedical Sciences, Monash University; Victoria 3800 Australia
- School of Molecular and Biomedical Science; University of Adelaide; North Terrace, Adelaide South Australia 5005 Australia
| | - Min Y. Yap
- Department of Biochemistry and Molecular Biology; School of Biomedical Sciences, Monash University; Victoria 3800 Australia
| | - Steven W. Polyak
- School of Molecular and Biomedical Science; University of Adelaide; North Terrace, Adelaide South Australia 5005 Australia
| | - Nathan P. Cowieson
- Department of Biochemistry and Molecular Biology; School of Biomedical Sciences, Monash University; Victoria 3800 Australia
- Monash Centre for Synchrotron Science; Monash University; Victoria 3800 Australia
| | - Andrew Abell
- School of Chemistry and Physics; University of Adelaide; North Terrace, Adelaide South Australia 5005 Australia
| | - Grant W. Booker
- School of Molecular and Biomedical Science; University of Adelaide; North Terrace, Adelaide South Australia 5005 Australia
| | - John C. Wallace
- School of Molecular and Biomedical Science; University of Adelaide; North Terrace, Adelaide South Australia 5005 Australia
| | - Jacqueline A. Wilce
- Department of Biochemistry and Molecular Biology; School of Biomedical Sciences, Monash University; Victoria 3800 Australia
| | - Matthew C. J. Wilce
- Department of Biochemistry and Molecular Biology; School of Biomedical Sciences, Monash University; Victoria 3800 Australia
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9
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Pendini NR, Yap MY, Traore DAK, Polyak SW, Cowieson NP, Abell A, Booker GW, Wallace JC, Wilce JA, Wilce MCJ. Structural characterization of Staphylococcus aureus biotin protein ligase and interaction partners: an antibiotic target. Protein Sci 2013; 22:762-73. [PMID: 23559560 DOI: 10.1002/pro.2262] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 03/26/2013] [Accepted: 03/26/2013] [Indexed: 11/06/2022]
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-5'-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.
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Affiliation(s)
- Nicole R Pendini
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Victoria, Australia
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10
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Bye JW, Cowieson NP, Cowieson AJ, Selle PH, Falconer RJ. Dual effects of sodium phytate on the structural stability and solubility of proteins. J Agric Food Chem 2013; 61:290-295. [PMID: 23252762 DOI: 10.1021/jf303926v] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The interaction between sodium phytate and three proteins was studied using solubility experiments and differential scanning calorimetry (DSC) to assess structural stability. Lysozyme, which is positively charged at neutral pH, bound phytate by an electrostatic interaction. There was evidence that phytate cross-linked lysozyme molecules forcing them out of solution. Myoglobin and human serum albumin, which were neutral or negatively charged, respectively, displayed association rather than binding, and there was no complex formation. All of the proteins were structurally destabilized by the presence of phytate but were not denatured. From these findings, we predict that phytate would bind electrostatically to a wide variety of positively charged proteins in the stomach as well as to trypsin and chymotrypsin in the duodenum. Both binding reactions may compromise the digestion of the protein component in feed stuffs. Because the interaction between phytate and protein is electrostatic, the presence of anions, such as chloride, would nullify the antinutritional effect of phytate.
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Affiliation(s)
- Jordan W Bye
- Department of Chemical and Biological Engineering, ChELSI Institute, University of Sheffield, Sheffield S1 3JD, United Kingdom
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11
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Lay FT, Mills GD, Poon IKH, Cowieson NP, Kirby N, Baxter AA, van der Weerden NL, Dogovski C, Perugini MA, Anderson MA, Kvansakul M, Hulett MD. Dimerization of plant defensin NaD1 enhances its antifungal activity. J Biol Chem 2012; 287:19961-72. [PMID: 22511788 PMCID: PMC3370180 DOI: 10.1074/jbc.m111.331009] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Revised: 04/16/2012] [Indexed: 11/06/2022] Open
Abstract
The plant defensin, NaD1, from the flowers of Nicotiana alata, is a member of a family of cationic peptides that displays growth inhibitory activity against several filamentous fungi, including Fusarium oxysporum. The antifungal activity of NaD1 has been attributed to its ability to permeabilize membranes; however, the molecular basis of this function remains poorly defined. In this study, we have solved the structure of NaD1 from two crystal forms to high resolution (1.4 and 1.58 Å, respectively), both of which contain NaD1 in a dimeric configuration. Using protein cross-linking experiments as well as small angle x-ray scattering analysis and analytical ultracentrifugation, we show that NaD1 forms dimers in solution. The structural studies identified Lys(4) as critical in formation of the NaD1 dimer. This was confirmed by site-directed mutagenesis of Lys(4) that resulted in substantially reduced dimer formation. Significantly, the reduced ability of the Lys(4) mutant to dimerize correlated with diminished antifungal activity. These data demonstrate the importance of dimerization in NaD1 function and have implications for the use of defensins in agribiotechnology applications such as enhancing plant crop protection against fungal pathogens.
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Affiliation(s)
- Fung T. Lay
- From the Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086
- Hexima Limited, Melbourne, Victoria 3000, and
| | - Grant D. Mills
- From the Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086
- Hexima Limited, Melbourne, Victoria 3000, and
| | - Ivan K. H. Poon
- From the Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086
| | - Nathan P. Cowieson
- the Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia
| | - Nigel Kirby
- the Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia
| | - Amy A. Baxter
- From the Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086
- Hexima Limited, Melbourne, Victoria 3000, and
| | - Nicole L. van der Weerden
- From the Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086
- Hexima Limited, Melbourne, Victoria 3000, and
| | - Con Dogovski
- From the Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086
| | - Matthew A. Perugini
- From the Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086
| | - Marilyn A. Anderson
- From the Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086
- Hexima Limited, Melbourne, Victoria 3000, and
| | - Marc Kvansakul
- From the Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086
| | - Mark D. Hulett
- From the Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086
- Hexima Limited, Melbourne, Victoria 3000, and
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12
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Nakatani Y, Cutfield SM, Cowieson NP, Cutfield JF. Structure and activity of exo-1,3/1,4-β-glucanase from marine bacterium Pseudoalteromonas sp. BB1 showing a novel C-terminal domain. FEBS J 2011; 279:464-78. [DOI: 10.1111/j.1742-4658.2011.08439.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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13
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Kim HS, Wilce MCJ, Yoga YMK, Pendini NR, Gunzburg MJ, Cowieson NP, Wilson GM, Williams BRG, Gorospe M, Wilce JA. Different modes of interaction by TIAR and HuR with target RNA and DNA. Nucleic Acids Res 2011; 39:1117-30. [PMID: 21233170 PMCID: PMC3035456 DOI: 10.1093/nar/gkq837] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
TIAR and HuR are mRNA-binding proteins that play important roles in the regulation of translation. They both possess three RNA recognition motifs (RRMs) and bind to AU-rich elements (AREs), with seemingly overlapping specificity. Here we show using SPR that TIAR and HuR bind to both U-rich and AU-rich RNA in the nanomolar range, with higher overall affinity for U-rich RNA. However, the higher affinity for U–rich sequences is mainly due to faster association with U-rich RNA, which we propose is a reflection of the higher probability of association. Differences between TIAR and HuR are observed in their modes of binding to RNA. TIAR is able to bind deoxy-oligonucleotides with nanomolar affinity, whereas HuR affinity is reduced to a micromolar level. Studies with U-rich DNA reveal that TIAR binding depends less on the 2′-hydroxyl group of RNA than HuR binding. Finally we show that SAXS data, recorded for the first two domains of TIAR in complex with RNA, are more consistent with a flexible, elongated shape and not the compact shape that the first two domains of Hu proteins adopt upon binding to RNA. We thus propose that these triple-RRM proteins, which compete for the same binding sites in cells, interact with their targets in fundamentally different ways.
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Affiliation(s)
- Henry S Kim
- Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
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14
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Pang SS, Berry R, Chen Z, Kjer-Nielsen L, Perugini MA, King GF, Wang C, Chew SH, La Gruta NL, Williams NK, Beddoe T, Tiganis T, Cowieson NP, Godfrey DI, Purcell AW, Wilce MCJ, McCluskey J, Rossjohn J. The structural basis for autonomous dimerization of the pre-T-cell antigen receptor. Nature 2010; 467:844-8. [PMID: 20944746 DOI: 10.1038/nature09448] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Accepted: 08/23/2010] [Indexed: 11/09/2022]
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.
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Affiliation(s)
- Siew Siew Pang
- The Protein Crystallography Unit, Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800, Australia
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15
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Abstract
Retromer is a peripheral membrane protein complex that has pleiotropic roles in endosomal membrane trafficking. The core of retromer possesses three subunits, VPS35, VPS29 and VPS26, that play different roles in binding to cargo, regulatory proteins and complex stabilization. We have performed an investigation of the thermodynamics of core retromer assembly using isothermal titration calorimetry (ITC) demonstrating that VPS35 acts as the central subunit to which VPS29 and VPS26 bind independently. Furthermore, we confirm that the conserved PRLYL motif of the large VPS35 subunit is critical for direct VPS26 interaction. Heat capacity measurements of VPS29 and VPS26 binding to VPS35 indicate extensive binding interfaces and suggest conformational alterations in VPS29 or VPS35 upon complex formation. Solution studies of the retromer core using small-angle X-ray scattering allow us to propose a model whereby VPS35 forms an extended platform with VPS29 and VPS26 bound at distal ends, with the potential for forming dimeric assemblies.
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Affiliation(s)
- Suzanne J Norwood
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland 4072, Australia
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16
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Cowieson NP, King G, Cookson D, Ross I, Huber T, Hume DA, Kobe B, Martin JL. Cortactin adopts a globular conformation and bundles actin into sheets. J Biol Chem 2008; 283:16187-93. [PMID: 18375393 DOI: 10.1074/jbc.m708917200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
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.
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Affiliation(s)
- Nathan P Cowieson
- Institute for Molecular Bioscience and Australian Research Council (ARC) Special Research Centre for Functional and Applied Genomics, University of Queensland, Brisbane QLD 4072 Australia
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17
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Robin G, Cowieson NP, Guncar G, Forwood JK, Listwan P, Hume DA, Kobe B, Martin JL, Huber T. A general target selection method for crystallographic proteomics. Methods Mol Biol 2008; 426:27-35. [PMID: 18542855 DOI: 10.1007/978-1-60327-058-8_2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Increasing the success in obtaining structures and maximizing the value of the structures determined are the two major goals of target selection in structural proteomics. This chapter presents an efficient and flexible target selection procedure supplemented with a Web-based resource that is suitable for small- to large-scale structural genomics projects that use crystallography as the major means of structure determination. Based on three criteria, biological significance, structural novelty, and "crystallizability," the approach first removes (filters) targets that do not meet minimal criteria and then ranks the remaining targets based on their "crystallizability" estimates. This novel procedure was designed to maximize selection efficiency, and its prevailing criteria categories make it suitable for a broad range of structural proteomics projects.
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Affiliation(s)
- Gautier Robin
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
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18
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Cowieson NP, Miles AJ, Robin G, Forwood JK, Kobe B, Martin JL, Wallace BA. Evaluating protein:protein complex formation using synchrotron radiation circular dichroism spectroscopy. Proteins 2007; 70:1142-6. [PMID: 17894344 DOI: 10.1002/prot.21631] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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.
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Affiliation(s)
- Nathan P Cowieson
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia.
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19
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Satoh T, Cowieson NP, Hakamata W, Ideo H, Fukushima K, Kurihara M, Kato R, Yamashita K, Wakatsuki S. Structural basis for recognition of high mannose type glycoproteins by mammalian transport lectin VIP36. J Biol Chem 2007; 282:28246-55. [PMID: 17652092 DOI: 10.1074/jbc.m703064200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
VIP36 functions as a transport lectin for trafficking certain high mannose type glycoproteins in the secretory pathway. Here we report the crystal structure of VIP36 exoplasmic/luminal domain comprising a carbohydrate recognition domain and a stalk domain. The structures of VIP36 in complex with Ca(2+) and mannosyl ligands are also described. The carbohydrate recognition domain is composed of a 17-stranded antiparallel beta-sandwich and binds one Ca(2+) adjoining the carbohydrate-binding site. The structure reveals that a coordinated Ca(2+) ion orients the side chains of Asp(131), Asn(166), and His(190) for carbohydrate binding. This result explains the Ca(2+)-dependent carbohydrate binding of this protein. The Man-alpha-1,2-Man-alpha-1,2-Man, which corresponds to the D1 arm of high mannose type glycan, is recognized by eight residues through extensive hydrogen bonds. The complex structures reveal the structural basis for high mannose type glycoprotein recognition by VIP36 in a Ca(2+)-dependent and D1 arm-specific manner.
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Affiliation(s)
- Tadashi Satoh
- Structural Biology Research Center, Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan
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20
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Kurz M, Cowieson NP, Robin G, Hume DA, Martin JL, Kobe B, Listwan P. Incorporating a TEV cleavage site reduces the solubility of nine recombinant mouse proteins. Protein Expr Purif 2006; 50:68-73. [PMID: 16798010 DOI: 10.1016/j.pep.2006.05.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2006] [Revised: 05/12/2006] [Accepted: 05/14/2006] [Indexed: 11/22/2022]
Abstract
Failure to express soluble proteins in bacteria is mainly attributed to the properties of the target protein itself, as well as the choice of the vector, the purification tag and the linker between the tag and protein, and codon usage. The expression of proteins with fusion tags to facilitate subsequent purification steps is a widely used procedure in the production of recombinant proteins. However, the additional residues can affect the properties of the protein; therefore, it is often desirable to remove the tag after purification. This is usually done by engineering a cleavage site between the tag and the encoded protein that is recognised by a site-specific protease, such as the one from tobacco etch virus (TEV). In this study, we investigated the effect of four different tags on the bacterial expression and solubility of nine mouse proteins. Two of the four engineered constructs contained hexahistidine tags with either a long or short linker. The other two constructs contained a TEV cleavage site engineered into the linker region. Our data show that inclusion of the TEV recognition site directly downstream of the recombination site of the Invitrogen Gateway vector resulted in a loss of solubility of the nine mouse proteins. Our work suggests that one needs to be very careful when making modifications to expression vectors and combining different affinity and fusion tags and cleavage sites.
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Affiliation(s)
- Mareike Kurz
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Qld 4072, Australia
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21
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Abstract
Insoluble expression of heterologous proteins in Escherichia coli is a major bottleneck of many structural genomics and high-throughput protein biochemistry projects. Many of these proteins may be amenable to refolding, but their identification is hampered by a lack of high-throughput methods. We have developed a matrix-assisted refolding approach in which correctly folded proteins are distinguished from misfolded proteins by their elution from affinity resin under non-denaturing conditions. Misfolded proteins remain adhered to the resin, presumably via hydrophobic interactions. The assay can be applied to insoluble proteins on an individual basis but is particularly well suited for high-throughput applications because it is rapid, automatable and has no rigorous sample preparation requirements. The efficacy of the screen is demonstrated on small-scale expression samples for 15 proteins. Refolding is then validated by large-scale expressions using SEC and circular dichroism.
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Affiliation(s)
- Nathan P Cowieson
- Institute for Molecular Bioscience and ARC Special Research Centre for Functional and Applied Genomics, University of Queensland, Brisbane, Queensland, Australia.
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22
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Cowieson NP, Listwan P, Kurz M, Aagaard A, Ravasi T, Wells C, Huber T, Hume DA, Kobe B, Martin JL. Pilot studies on the parallel production of soluble mouse proteins in a bacterial expression system. ACTA ACUST UNITED AC 2005; 6:13-20. [PMID: 15965734 DOI: 10.1007/s10969-005-0462-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2004] [Accepted: 01/05/2005] [Indexed: 10/25/2022]
Abstract
We investigated the parallel production in medium throughput of mouse proteins, using protocols that involved recombinatorial cloning, protein expression screening and batch purification. The methods were scaled up to allow the simultaneous processing of tens or hundreds of protein samples. Scale-up was achieved in two stages. In an initial study, 30 targets were processed manually but with common protocols for all targets. In the second study, these protocols were applied to 96 target proteins that were processed in an automated manner. The success rates at each stage of the study were similar for both the manual and automated approaches. Overall, 15 of the selected 126 target mouse genes (12%) yielded soluble protein products in a bacterial expression system. This success rate compares favourably with other protein screening projects, particularly for eukaryotic proteins, and could be further improved by modifications at the cloning step.
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23
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Cowieson NP, Partridge JF, Allshire RC, McLaughlin PJ. Dimerisation of a chromo shadow domain and distinctions from the chromodomain as revealed by structural analysis. Curr Biol 2000; 10:517-25. [PMID: 10801440 DOI: 10.1016/s0960-9822(00)00467-x] [Citation(s) in RCA: 191] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Proteins such as HP1, found in fruit flies and mammals, and Swi6, its fission yeast homologue, carry a chromodomain (CD) and a chromo shadow domain (CSD). These proteins are required to form functional transcriptionally silent centromeric chromatin, and their mutation leads to chromosome segregation defects. CSDs have only been found in tandem in proteins containing the related CD. Most HP1-interacting proteins have been found to associate through the CSD and many of these ligands contain a conserved pentapeptide motif. RESULTS The 1.9 A crystal structure of the Swi6 CSD is presented here. This reveals a novel dimeric structure that is distinct from the previously reported monomeric nuclear magnetic resonance (NMR) structure of the CD from the mouse modifier 1 protein (MoMOD1, also known as HP1beta or M31). A prominent pit with a non-polar base is generated at the dimer interface, and is commensurate with binding an extended pentapeptide motif. Sequence alignments based on this structure highlight differences between CDs and CSDs that are superimposed on a common structural core. The analyses also revealed a previously unrecognised circumferential hydrophobic sash around the surface of the CD structure. CONCLUSIONS Dimerisation through the CSD of HP1-like proteins results in the simultaneous formation of a putative protein-protein interaction pit, providing a potential means of targeting CSD-containing proteins to particular chromatin sites.
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Affiliation(s)
- N P Cowieson
- Swann Building, King's Buildings, Institute of Cell and Molecular Biology, The University of Edinburgh, Edinburgh, EH9 3JR, Scotland
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