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Chavas LMG, Coulibaly F, Garriga D. Bridging the microscopic divide: a comprehensive overview of micro-crystallization and in vivo crystallography. IUCRJ 2024; 11:476-485. [PMID: 38958014 PMCID: PMC11220871 DOI: 10.1107/s205225252400513x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Accepted: 05/30/2024] [Indexed: 07/04/2024]
Abstract
A series of events underscoring the significant advancements in micro-crystallization and in vivo crystallography were held during the 26th IUCr Congress in Melbourne, positioning microcrystallography as a pivotal field within structural biology. Through collaborative discussions and the sharing of innovative methodologies, these sessions outlined frontier approaches in macromolecular crystallography. This review provides an overview of this rapidly moving field in light of the rich dialogues and forward-thinking proposals explored during the congress workshop and microsymposium. These advances in microcrystallography shed light on the potential to reshape current research paradigms and enhance our comprehension of biological mechanisms at the molecular scale.
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Affiliation(s)
| | - Fasséli Coulibaly
- Biomedicine Discovery Institute & Department of Biochemistry and Molecular BiologyMonash UniversityClaytonAustralia
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2
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Mehrabi P, Schulz EC. Sample Preparation for Time-Resolved Serial Crystallography: Practical Considerations. Methods Mol Biol 2023; 2652:361-379. [PMID: 37093487 DOI: 10.1007/978-1-0716-3147-8_21] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Time-resolved serial crystallography is an emerging method to elucidate the structure-function relationship of biomolecular systems at up to atomic resolution. However, to make this demanding method a success, a number of experimental requirements have to be met. In this chapter, we summarize general guidelines and protocols towards performing time-resolved crystallography experiments, with a particular emphasis on sample requirements and preparation but also a brief excursion into reaction initiation.
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Affiliation(s)
- Pedram Mehrabi
- Institute for Nanostructure and Solid State Physics, Universität Hamburg, Hamburg, Germany.
- Max Planck Institute for Structure and Dynamics of Matter, Hamburg, Germany.
| | - Eike C Schulz
- Max Planck Institute for Structure and Dynamics of Matter, Hamburg, Germany.
- University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany.
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3
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Exploring Nucleation Pathways in Distinct Physicochemical Environments Unveiling Novel Options to Modulate and Optimize Protein Crystallization. CRYSTALS 2022. [DOI: 10.3390/cryst12030437] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The scientific discussion about classical and nonclassical nucleation theories has lasted for two decades so far. Recently, multiple nucleation pathways and the occurrence and role of metastable intermediates in crystallization processes have attracted increasing attention, following the discovery of functional phase separation, which is now under investigation in different fields of cellular life sciences, providing interesting and novel aspects for conventional crystallization experiments. In this context, more systematic investigations need to be carried out to extend the current knowledge about nucleation processes. In terms of the data we present, a well-studied model protein, glucose isomerase (GI), was employed first to investigate systematically the early stages of the crystallization process, covering condensing and prenucleation ordering of protein molecules in diverse scenarios, including varying ionic and crowding agent conditions, as well as the application of a pulsed electric field (pEF). The main method used to characterize the early events of nucleation was synchronized polarized and depolarized dynamic light scattering (DLS/DDLS), which is capable of collecting the polarized and depolarized component of scattered light from a sample suspension in parallel, thus monitoring the time-resolved evolution of the condensation and geometrical ordering of proteins at the early stages of nucleation. A diffusion interaction parameter, KD, of GI under varying salt conditions was evaluated to discuss how the proportion of specific and non-specific protein–protein interactions affects the nucleation process. The effect of mesoscopic ordered clusters (MOCs) on protein crystallization was explored further by adding different ratios of MOCs induced by a pEF to fresh GI droplets in solution with different PEG concentrations. To emphasize and complement the data and results obtained with GI, a recombinant pyridoxal 5-phosphate (vitamin B6) synthase (Pdx) complex of Staphylococcus aureus assembled from twelve monomers of Pdx1 and twelve monomers of Pdx2 was employed to validate the ability of the pEF influencing the nucleation of complex macromolecules and the effect of MOCs on adjusting the crystallization pathway. In summary, our data revealed multiple nucleation pathways by tuning the proportion of specific and non-specific protein interactions, or by utilizing a pEF which turned out to be efficient to accelerate the nucleation process. Finally, a novel and reproducible experimental strategy, which can adjust and facilitate a crystallization process by pEF-induced MOCs, was summarized and reported for the first time.
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Abstract
Focus a laser on dissolved particles and analyze the scattered light to reveal their size. This well established principle is used in dynamic light scattering (DLS), or also called photon-correlation spectroscopy, which is a widely popular and highly adaptable analytical method applied in different fields of life and material sciences, as well as in industrial quality control processes.
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Affiliation(s)
- Alice S. Pereira
- grid.10772.330000000121511713Molecular Biophysics Lab., UCIBIO/Requimte, Department of Chemistry, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Pedro Tavares
- grid.10772.330000000121511713Molecular Biophysics Lab., UCIBIO/Requimte, Department of Chemistry, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Paulo Limão-Vieira
- grid.10772.330000000121511713Atomic and Molecular Collisions Laboratory, CEFITEC, Department of Physics, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
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5
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Kwan TOC, Reis R, Siligardi G, Hussain R, Cheruvara H, Moraes I. Selection of Biophysical Methods for Characterisation of Membrane Proteins. Int J Mol Sci 2019; 20:E2605. [PMID: 31137900 PMCID: PMC6566885 DOI: 10.3390/ijms20102605] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 05/22/2019] [Accepted: 05/24/2019] [Indexed: 02/01/2023] Open
Abstract
Over the years, there have been many developments and advances in the field of integral membrane protein research. As important pharmaceutical targets, it is paramount to understand the mechanisms of action that govern their structure-function relationships. However, the study of integral membrane proteins is still incredibly challenging, mostly due to their low expression and instability once extracted from the native biological membrane. Nevertheless, milligrams of pure, stable, and functional protein are always required for biochemical and structural studies. Many modern biophysical tools are available today that provide critical information regarding to the characterisation and behaviour of integral membrane proteins in solution. These biophysical approaches play an important role in both basic research and in early-stage drug discovery processes. In this review, it is not our objective to present a comprehensive list of all existing biophysical methods, but a selection of the most useful and easily applied to basic integral membrane protein research.
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Affiliation(s)
- Tristan O C Kwan
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK.
- Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot OX11 0FA, UK.
| | - Rosana Reis
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK.
- Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot OX11 0FA, UK.
| | - Giuliano Siligardi
- Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK.
| | - Rohanah Hussain
- Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK.
| | - Harish Cheruvara
- Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot OX11 0FA, UK.
- Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK.
| | - Isabel Moraes
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK.
- Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot OX11 0FA, UK.
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6
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Munawar A, Ali SA, Akrem A, Betzel C. Snake Venom Peptides: Tools of Biodiscovery. Toxins (Basel) 2018; 10:toxins10110474. [PMID: 30441876 PMCID: PMC6266942 DOI: 10.3390/toxins10110474] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 10/30/2018] [Accepted: 11/07/2018] [Indexed: 01/09/2023] Open
Abstract
Nature endowed snakes with a lethal secretion known as venom, which has been fine-tuned over millions of years of evolution. Snakes utilize venom to subdue their prey and to survive in their natural habitat. Venom is known to be a very poisonous mixture, consisting of a variety of molecules, such as carbohydrates, nucleosides, amino acids, lipids, proteins and peptides. Proteins and peptides are the major constituents of the dry weight of snake venoms and are of main interest for scientific investigations as well as for various pharmacological applications. Snake venoms contain enzymatic and non-enzymatic proteins and peptides, which are grouped into different families based on their structure and function. Members of a single family display significant similarities in their primary, secondary and tertiary structures, but in many cases have distinct pharmacological functions and different bioactivities. The functional specificity of peptides belonging to the same family can be attributed to subtle variations in their amino acid sequences. Currently, complementary tools and techniques are utilized to isolate and characterize the peptides, and study their potential applications as molecular probes, and possible templates for drug discovery and design investigations.
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Affiliation(s)
- Aisha Munawar
- Department of Chemistry, University of Engineering and Technology, Lahore 54890, Pakistan.
| | - Syed Abid Ali
- H.E. J. Research Institute of Chemistry, (ICCBS), University of Karachi, Karachi 75270, Pakistan.
| | - Ahmed Akrem
- Botany Division, Institute of Pure and Applied Biology, Bahauddin Zakariya University, Multan 60800, Pakistan.
| | - Christian Betzel
- Department of Chemistry, Institute of Biochemistry and Molecular Biology, University of Hamburg, 22607 Hamburg, Germany.
- Laboratory for Structural Biology of Infection and Inflammation, DESY, Build. 22a, Notkestr. 85, 22603 Hamburg, Germany.
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Birch J, Axford D, Foadi J, Meyer A, Eckhardt A, Thielmann Y, Moraes I. The fine art of integral membrane protein crystallisation. Methods 2018; 147:150-162. [PMID: 29778646 DOI: 10.1016/j.ymeth.2018.05.014] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 05/13/2018] [Accepted: 05/15/2018] [Indexed: 11/29/2022] Open
Abstract
Integral membrane proteins are among the most fascinating and important biomolecules as they play a vital role in many biological functions. Knowledge of their atomic structures is fundamental to the understanding of their biochemical function and key in many drug discovery programs. However, over the years, structure determination of integral membrane proteins has proven to be far from trivial, hence they are underrepresented in the protein data bank. Low expression levels, insolubility and instability are just a few of the many hurdles one faces when studying these proteins. X-ray crystallography has been the most used method to determine atomic structures of membrane proteins. However, the production of high quality membrane protein crystals is always very challenging, often seen more as art than a rational experiment. Here we review valuable approaches, methods and techniques to successful membrane protein crystallisation.
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Affiliation(s)
- James Birch
- Membrane Protein Laboratory, Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot OX11 0FA, UK
| | - Danny Axford
- Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE, UK
| | - James Foadi
- Department of Mathematical Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Arne Meyer
- XtalConcepts GmbH, Schnackenburgallee 13, 22525 Hamburg, Germany
| | - Annette Eckhardt
- XtalConcepts GmbH, Schnackenburgallee 13, 22525 Hamburg, Germany
| | - Yvonne Thielmann
- Max Planck Institute of Biophysics, Molecular Membrane Biology, Max-von-Laue-Strasse 3, 60438 Frankfurt, Germany
| | - Isabel Moraes
- Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot OX11 0FA, UK; Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE, UK; National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK.
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Falke S, Dierks K, Blanchet C, Graewert M, Cipriani F, Meijers R, Svergun D, Betzel C. Multi-channel in situ dynamic light scattering instrumentation enhancing biological small-angle X-ray scattering experiments at the PETRA III beamline P12. JOURNAL OF SYNCHROTRON RADIATION 2018; 25:361-372. [PMID: 29488914 DOI: 10.1107/s1600577517017568] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 12/07/2017] [Indexed: 06/08/2023]
Abstract
Small-angle X-ray scattering (SAXS) analysis of biomolecules is increasingly common with a constantly high demand for comprehensive and efficient sample quality control prior to SAXS experiments. As monodisperse sample suspensions are desirable for SAXS experiments, latest dynamic light scattering (DLS) techniques are most suited to obtain non-invasive and rapid information about the particle size distribution of molecules in solution. A multi-receiver four-channel DLS system was designed and adapted at the BioSAXS endstation of the EMBL beamline P12 at PETRA III (DESY, Hamburg, Germany). The system allows the collection of DLS data within round-shaped sample capillaries used at beamline P12. Data obtained provide information about the hydrodynamic radius of biological particles in solution and dispersity of the solution. DLS data can be collected directly prior to and during an X-ray exposure. To match the short X-ray exposure times of around 1 s for 20 exposures at P12, the DLS data collection periods that have been used up to now of 20 s or commonly more were substantially reduced, using a novel multi-channel approach collecting DLS data sets in the SAXS sample capillary at four different neighbouring sample volume positions in parallel. The setup allows online scoring of sample solutions applied for SAXS experiments, supports SAXS data evaluation and for example indicates local inhomogeneities in a sample solution in a time-efficient manner. Biological macromolecules with different molecular weights were applied to test the system and obtain information about the performance. All measured hydrodynamic radii are in good agreement with DLS results obtained by employing a standard cuvette instrument. Moreover, applying the new multi-channel DLS setup, a reliable radius determination of sample solutions in flow, at flow rates normally used for size-exclusion chromatography-SAXS experiments, and at higher flow rates, was verified as well. This study also shows and confirms that the newly designed sample compartment with attached DLS instrumentation does not disturb SAXS measurements.
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Affiliation(s)
- Sven Falke
- Laboratory for Structural Biology of Infection and Inflammation, University Hamburg, c/o DESY, Building 22a, Notkestrasse 85, Hamburg 22603, Germany
| | - Karsten Dierks
- Xtal Concepts GmbH, Marlowring 19, Hamburg 22525, Germany
| | - Clement Blanchet
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation, c/o Notkestrasse 85, Hamburg 22607, Germany
| | - Melissa Graewert
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation, c/o Notkestrasse 85, Hamburg 22607, Germany
| | - Florent Cipriani
- European Molecular Biology Laboratory (EMBL), 71 Avenue des Martyrs, Grenoble 38042, France
| | - Rob Meijers
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation, c/o Notkestrasse 85, Hamburg 22607, Germany
| | - Dmitri Svergun
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation, c/o Notkestrasse 85, Hamburg 22607, Germany
| | - Christian Betzel
- Laboratory for Structural Biology of Infection and Inflammation, University Hamburg, c/o DESY, Building 22a, Notkestrasse 85, Hamburg 22603, Germany
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9
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Hopkins JB, Thorne RE. Quantifying radiation damage in biomolecular small-angle X-ray scattering. J Appl Crystallogr 2016; 49:880-890. [PMID: 27275138 PMCID: PMC4886981 DOI: 10.1107/s1600576716005136] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 03/25/2016] [Indexed: 11/10/2022] Open
Abstract
Small-angle X-ray scattering (SAXS) is an increasingly popular technique that provides low-resolution structural information about biological macromolecules in solution. Many of the practical limitations of the technique, such as minimum required sample volume, and of experimental design, such as sample flow cells, are necessary because the biological samples are sensitive to damage from the X-rays. Radiation damage typically manifests as aggregation of the sample, which makes the collected data unreliable. However, there has been little systematic investigation of the most effective methods to reduce damage rates, and results from previous damage studies are not easily compared with results from other beamlines. Here a methodology is provided for quantifying radiation damage in SAXS to provide consistent results between different experiments, experimenters and beamlines. These methods are demonstrated on radiation damage data collected from lysozyme, glucose isomerase and xylanase, and it is found that no single metric is sufficient to describe radiation damage in SAXS for all samples. The radius of gyration, molecular weight and integrated SAXS profile intensity constitute a minimal set of parameters that capture all types of observed behavior. Radiation sensitivities derived from these parameters show a large protein dependence, varying by up to six orders of magnitude between the different proteins tested. This work should enable consistent reporting of radiation damage effects, allowing more systematic studies of the most effective minimization strategies.
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Affiliation(s)
| | - Robert E. Thorne
- Department of Physics, Cornell University, Ithaca, NY 14853, USA
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10
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Utilisation of adsorption and desorption for simultaneously improving protein crystallisation success rate and crystal quality. Sci Rep 2014; 4:7308. [PMID: 25471817 PMCID: PMC4255177 DOI: 10.1038/srep07308] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 11/11/2014] [Indexed: 11/21/2022] Open
Abstract
High-quality protein crystals of suitable size are an important prerequisite for applying X-ray crystallography to determine the 3-dimensional structure of proteins. However, it is often difficult to obtain protein crystals of appropriate size and quality because nucleation and growth processes can be unsuccessful. Here, we show that by adsorbing proteins onto porous polystyrene-divinylbenzene microspheres (SDB) floating on the surface of the crystallisation solution, a localised high supersaturation region at the surface of the microspheres and a low supersaturation region below the microspheres can coexist in a single solution. The crystals will easily nucleate in the region of high supersaturation, but when they grow to a certain size, they will sediment to the region of low supersaturation and continue to grow. In this way, the probability of crystallisation and crystal quality can be simultaneously increased in a single solution without changing other crystallisation parameters.
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12
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Krauss IR, Merlino A, Vergara A, Sica F. An overview of biological macromolecule crystallization. Int J Mol Sci 2013; 14:11643-91. [PMID: 23727935 PMCID: PMC3709751 DOI: 10.3390/ijms140611643] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 05/08/2013] [Accepted: 05/20/2013] [Indexed: 12/11/2022] Open
Abstract
The elucidation of the three dimensional structure of biological macromolecules has provided an important contribution to our current understanding of many basic mechanisms involved in life processes. This enormous impact largely results from the ability of X-ray crystallography to provide accurate structural details at atomic resolution that are a prerequisite for a deeper insight on the way in which bio-macromolecules interact with each other to build up supramolecular nano-machines capable of performing specialized biological functions. With the advent of high-energy synchrotron sources and the development of sophisticated software to solve X-ray and neutron crystal structures of large molecules, the crystallization step has become even more the bottleneck of a successful structure determination. This review introduces the general aspects of protein crystallization, summarizes conventional and innovative crystallization methods and focuses on the new strategies utilized to improve the success rate of experiments and increase crystal diffraction quality.
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Affiliation(s)
- Irene Russo Krauss
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario di Monte Sant’Angelo, Via Cintia, Napoli I-80126, Italy; E-Mails: (I.R.K.); (A.M.); (A.V.)
| | - Antonello Merlino
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario di Monte Sant’Angelo, Via Cintia, Napoli I-80126, Italy; E-Mails: (I.R.K.); (A.M.); (A.V.)
- Institute of Biostructures and Bioimages, C.N.R, Via Mezzocannone 16, Napoli I-80134, Italy
| | - Alessandro Vergara
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario di Monte Sant’Angelo, Via Cintia, Napoli I-80126, Italy; E-Mails: (I.R.K.); (A.M.); (A.V.)
- Institute of Biostructures and Bioimages, C.N.R, Via Mezzocannone 16, Napoli I-80134, Italy
| | - Filomena Sica
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario di Monte Sant’Angelo, Via Cintia, Napoli I-80126, Italy; E-Mails: (I.R.K.); (A.M.); (A.V.)
- Institute of Biostructures and Bioimages, C.N.R, Via Mezzocannone 16, Napoli I-80134, Italy
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +39-81-674-479; Fax: +39-81-674-090
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13
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Bonander N, Jamshad M, Oberthür D, Clare M, Barwell J, Hu K, Farquhar MJ, Stamataki Z, Harris HJ, Dierks K, Dafforn TR, Betzel C, McKeating JA, Bill RM. Production, purification and characterization of recombinant, full-length human claudin-1. PLoS One 2013; 8:e64517. [PMID: 23704991 PMCID: PMC3660353 DOI: 10.1371/journal.pone.0064517] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 04/16/2013] [Indexed: 01/20/2023] Open
Abstract
The transmembrane domain proteins of the claudin superfamily are the major structural components of cellular tight junctions. One family member, claudin-1, also associates with tetraspanin CD81 as part of a receptor complex that is essential for hepatitis C virus (HCV) infection of the liver. To understand the molecular basis of claudin-1/CD81 association we previously produced and purified milligram quantities of functional, full-length CD81, which binds a soluble form of HCV E2 glycoprotein (sE2). Here we report the production, purification and characterization of claudin-1. Both yeast membrane-bound and detergent-extracted, purified claudin-1 were antigenic and recognized by specific antibodies. Analytical ultracentrifugation demonstrated that extraction with n-octyl-β-d-glucopyranoside yielded monodispersed, dimeric pools of claudin-1 while extraction with profoldin-8 or n-decylphosphocholine yielded a dynamic mixture of claudin-1 oligomers. Neither form bound sE2 in line with literature expectations, while further functional analysis was hampered by the finding that incorporation of claudin-1 into proteoliposomes rendered them intractable to study. Dynamic light scattering demonstrated that claudin-1 oligomers associate with CD81 in vitro in a defined molar ratio of 1∶2 and that complex formation was enhanced by the presence of cholesteryl hemisuccinate. Attempts to assay the complex biologically were limited by our finding that claudin-1 affects the properties of proteoliposomes. We conclude that recombinant, correctly-folded, full-length claudin-1 can be produced in yeast membranes, that it can be extracted in different oligomeric forms that do not bind sE2 and that a dynamic preparation can form a specific complex with CD81 in vitro in the absence of any other cellular components. These findings pave the way for the structural characterization of claudin-1 alone and in complex with CD81.
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Affiliation(s)
- Nicklas Bonander
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, United Kingdom
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Gangloff M, Moreno A, Gay NJ. Liesegang-like patterns of Toll crystals grown in gel. J Appl Crystallogr 2013; 46:337-345. [PMID: 23596340 PMCID: PMC3627410 DOI: 10.1107/s0021889812051606] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Accepted: 12/21/2012] [Indexed: 11/14/2022] Open
Abstract
Generating high-quality crystals remains a bottleneck in biological and materials sciences. Here a counter-diffusion method was used to improve the X-ray diffraction quality of the N-terminal domain of Drosophila melanogaster Toll receptor crystals. It was observed that crystallization occurred with a peculiar pattern along the capillary resembling Liesegang bands; this phenomenon is described at both macroscopic and atomic levels. It was found that bands appeared for native protein as well as for co-crystals of magic triangle (I3C)-bound protein even though they crystallize in different space groups. Crystallization occurred with a linear recurrence independent of the precipitant concentration and a protein-specific spacing coefficient. Bandwidth varied along the capillary, oscillating between large precipitation areas and single crystals. The reported data suggest that repetitive patterns can be generated with biological macromolecules in the presence of sodium malonate as a crystallization agent. A comparison with typical Liesegang patterns and the possible mechanism underlying this phenomenon are discussed.
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Affiliation(s)
- Monique Gangloff
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
| | - Abel Moreno
- Instituto de Química, Universidad Nacional Autónoma de México, Mexico DF 04510, Mexico
| | - Nicholas J. Gay
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
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