1
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Sigmund F, Berezin O, Beliakova S, Magerl B, Drawitsch M, Piovesan A, Gonçalves F, Bodea SV, Winkler S, Bousraou Z, Grosshauser M, Samara E, Pujol-Martí J, Schädler S, So C, Irsen S, Walch A, Kofler F, Piraud M, Kornfeld J, Briggman K, Westmeyer GG. Genetically encoded barcodes for correlative volume electron microscopy. Nat Biotechnol 2023; 41:1734-1745. [PMID: 37069313 PMCID: PMC10713455 DOI: 10.1038/s41587-023-01713-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Accepted: 02/14/2023] [Indexed: 04/19/2023]
Abstract
While genetically encoded reporters are common for fluorescence microscopy, equivalent multiplexable gene reporters for electron microscopy (EM) are still scarce. Here, by installing a variable number of fixation-stable metal-interacting moieties in the lumen of encapsulin nanocompartments of different sizes, we developed a suite of spherically symmetric and concentric barcodes (EMcapsulins) that are readable by standard EM techniques. Six classes of EMcapsulins could be automatically segmented and differentiated. The coding capacity was further increased by arranging several EMcapsulins into distinct patterns via a set of rigid spacers of variable length. Fluorescent EMcapsulins were expressed to monitor subcellular structures in light and EM. Neuronal expression in Drosophila and mouse brains enabled the automatic identification of genetically defined cells in EM. EMcapsulins are compatible with transmission EM, scanning EM and focused ion beam scanning EM. The expandable palette of genetically controlled EM-readable barcodes can augment anatomical EM images with multiplexed gene expression maps.
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Affiliation(s)
- Felix Sigmund
- Munich Institute of Biomedical Engineering, Department of Bioscience, TUM School of Natural Sciences and TUM School of Medicine, Technical University of Munich, Munich, Germany
- Institute for Synthetic Biomedicine, Helmholtz Munich, Neuherberg, Germany
| | - Oleksandr Berezin
- Munich Institute of Biomedical Engineering, Department of Bioscience, TUM School of Natural Sciences and TUM School of Medicine, Technical University of Munich, Munich, Germany
- Institute for Synthetic Biomedicine, Helmholtz Munich, Neuherberg, Germany
| | - Sofia Beliakova
- Munich Institute of Biomedical Engineering, Department of Bioscience, TUM School of Natural Sciences and TUM School of Medicine, Technical University of Munich, Munich, Germany
- Institute for Synthetic Biomedicine, Helmholtz Munich, Neuherberg, Germany
| | - Bernhard Magerl
- Munich Institute of Biomedical Engineering, Department of Bioscience, TUM School of Natural Sciences and TUM School of Medicine, Technical University of Munich, Munich, Germany
- Institute for Synthetic Biomedicine, Helmholtz Munich, Neuherberg, Germany
| | - Martin Drawitsch
- Research Group, Circuits of Birdsong, Max Planck Institute for Biological Intelligence, Martinsried, Germany
| | - Alberto Piovesan
- Munich Institute of Biomedical Engineering, Department of Bioscience, TUM School of Natural Sciences and TUM School of Medicine, Technical University of Munich, Munich, Germany
- Institute for Synthetic Biomedicine, Helmholtz Munich, Neuherberg, Germany
| | - Filipa Gonçalves
- Munich Institute of Biomedical Engineering, Department of Bioscience, TUM School of Natural Sciences and TUM School of Medicine, Technical University of Munich, Munich, Germany
- Institute for Synthetic Biomedicine, Helmholtz Munich, Neuherberg, Germany
| | - Silviu-Vasile Bodea
- Munich Institute of Biomedical Engineering, Department of Bioscience, TUM School of Natural Sciences and TUM School of Medicine, Technical University of Munich, Munich, Germany
- Institute for Synthetic Biomedicine, Helmholtz Munich, Neuherberg, Germany
| | - Stefanie Winkler
- Institute for Synthetic Biomedicine, Helmholtz Munich, Neuherberg, Germany
| | - Zoe Bousraou
- Munich Institute of Biomedical Engineering, Department of Bioscience, TUM School of Natural Sciences and TUM School of Medicine, Technical University of Munich, Munich, Germany
- Institute for Synthetic Biomedicine, Helmholtz Munich, Neuherberg, Germany
| | - Martin Grosshauser
- Munich Institute of Biomedical Engineering, Department of Bioscience, TUM School of Natural Sciences and TUM School of Medicine, Technical University of Munich, Munich, Germany
- Institute for Synthetic Biomedicine, Helmholtz Munich, Neuherberg, Germany
| | - Eleni Samara
- Department Circuits-Computation-Models, Max Planck Institute for Biological Intelligence, Martinsried, Germany
| | - Jesús Pujol-Martí
- Department Circuits-Computation-Models, Max Planck Institute for Biological Intelligence, Martinsried, Germany
| | | | - Chun So
- Department of Meiosis, Max Planck Institute for Multidisciplinary Sciences, Goettingen, Germany
| | - Stephan Irsen
- Max Planck Institute for Neurobiology of Behavior-caesar (MPINB), Bonn, Germany
| | - Axel Walch
- Research Unit Analytical Pathology, Helmholtz Zentrum München, Neuherberg, Germany
| | | | - Marie Piraud
- Helmholtz AI, Helmholtz Munich, Neuherberg, Germany
| | - Joergen Kornfeld
- Research Group, Circuits of Birdsong, Max Planck Institute for Biological Intelligence, Martinsried, Germany
| | - Kevin Briggman
- Max Planck Institute for Neurobiology of Behavior-caesar (MPINB), Bonn, Germany
| | - Gil Gregor Westmeyer
- Munich Institute of Biomedical Engineering, Department of Bioscience, TUM School of Natural Sciences and TUM School of Medicine, Technical University of Munich, Munich, Germany.
- Institute for Synthetic Biomedicine, Helmholtz Munich, Neuherberg, Germany.
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2
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Monzon AM, Arrías PN, Elofsson A, Mier P, Andrade-Navarro MA, Bevilacqua M, Clementel D, Bateman A, Hirsh L, Fornasari MS, Parisi G, Piovesan D, Kajava AV, Tosatto SCE. A STRP-ed definition of Structured Tandem Repeats in Proteins. J Struct Biol 2023; 215:108023. [PMID: 37652396 DOI: 10.1016/j.jsb.2023.108023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 07/31/2023] [Accepted: 08/28/2023] [Indexed: 09/02/2023]
Abstract
Tandem Repeat Proteins (TRPs) are a class of proteins with repetitive amino acid sequences that have been studied extensively for over two decades. Different features at the level of sequence, structure, function and evolution have been attributed to them by various authors. And yet many of its salient features appear only when looking at specific subclasses of protein tandem repeats. Here, we attempt to rationalize the existing knowledge on Tandem Repeat Proteins (TRPs) by pointing out several dichotomies. The emerging picture is more nuanced than generally assumed and allows us to draw some boundaries of what is not a "proper" TRP. We conclude with an operational definition of a specific subset, which we have denominated STRPs (Structural Tandem Repeat Proteins), which separates a subclass of tandem repeats with distinctive features from several other less well-defined types of repeats. We believe that this definition will help researchers in the field to better characterize the biological meaning of this large yet largely understudied group of proteins.
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Affiliation(s)
- Alexander Miguel Monzon
- Dept. of Information Engineering, University of Padova, via Giovanni Gradenigo 6/B, 35131 Padova, Italy
| | - Paula Nazarena Arrías
- Dept. of Biomedical Sciences, University of Padova, via U. Bassi 58/b, 35121 Padova, Italy
| | - Arne Elofsson
- Dept. of Biochemistry and Biophysics and Science for Life Laboratory, Stockholm University, Tomtebodavägen 23, 171 21 Solna, Sweden
| | - Pablo Mier
- Institute of Organismic and Molecular Evolution, Faculty of Biology, Johannes Gutenberg University of Mainz, Hanns-Dieter-Hüsch-Weg 15, 55128 Mainz, Germany
| | - Miguel A Andrade-Navarro
- Institute of Organismic and Molecular Evolution, Faculty of Biology, Johannes Gutenberg University of Mainz, Hanns-Dieter-Hüsch-Weg 15, 55128 Mainz, Germany
| | - Martina Bevilacqua
- Dept. of Biomedical Sciences, University of Padova, via U. Bassi 58/b, 35121 Padova, Italy
| | - Damiano Clementel
- Dept. of Biomedical Sciences, University of Padova, via U. Bassi 58/b, 35121 Padova, Italy
| | - Alex Bateman
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - Layla Hirsh
- Dept. of Engineering, Faculty of Science and Engineering, Pontifical Catholic University of Peru, Av. Universitaria 1801 San Miguel, Lima 32, Lima, Peru
| | - Maria Silvina Fornasari
- Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, CONICET, Bernal, Buenos Aires, Argentina
| | - Gustavo Parisi
- Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, CONICET, Bernal, Buenos Aires, Argentina
| | - Damiano Piovesan
- Dept. of Biomedical Sciences, University of Padova, via U. Bassi 58/b, 35121 Padova, Italy
| | - Andrey V Kajava
- Centre de Recherche en Biologie cellulaire de Montpellier (CRBM), UMR 5237 CNRS, Université Montpellier, 1919 Route de Mende, Cedex 5, 34293 Montpellier, France
| | - Silvio C E Tosatto
- Dept. of Biomedical Sciences, University of Padova, via U. Bassi 58/b, 35121 Padova, Italy.
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3
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Boni R, Blackburn EA, Kleinjan DJ, Jonaitis M, Hewitt-Harris F, Murdoch M, Rosser S, Hay DC, Regan L. Chemically cross-linked hydrogels from repetitive protein arrays. J Struct Biol 2023; 215:107981. [PMID: 37245604 DOI: 10.1016/j.jsb.2023.107981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 05/19/2023] [Accepted: 05/23/2023] [Indexed: 05/30/2023]
Abstract
Biomaterials for tissue regeneration must mimic the biophysical properties of the native physiological environment. A protein engineering approach allows the generation of protein hydrogels with specific and customised biophysical properties designed to suit a particular physiological environment. Herein, repetitive engineered proteins were successfully designed to form covalent molecular networks with defined physical characteristics able to sustain cell phenotype. Our hydrogel design was made possible by the incorporation of the SpyTag (ST) peptide and multiple repetitive units of the SpyCatcher (SC) protein that spontaneously formed covalent crosslinks upon mixing. Changing the ratios of the protein building blocks (ST:SC), allowed the viscoelastic properties and gelation speeds of the hydrogels to be altered and controlled. The physical properties of the hydrogels could readily be altered further to suit different environments by tuning the key features in the repetitive protein sequence. The resulting hydrogels were designed with a view to allow cell attachment and encapsulation of liver derived cells. Biocompatibility of the hydrogels was assayed using a HepG2 cell line constitutively expressing GFP. The cells remained viable and continued to express GFP whilst attached or encapsulated within the hydrogel. Our results demonstrate how this genetically encoded approach using repetitive proteins could be applied to bridge engineering biology with nanotechnology creating a level of biomaterial customisation previously inaccessible.
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Affiliation(s)
- Rossana Boni
- Centre for Engineering Biology, Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Elizabeth A Blackburn
- Edinburgh Protein Production Facility (EPPF), University of Edinburgh, Edinburgh, United Kingdom
| | - Dirk-Jan Kleinjan
- UK Centre for Mammalian Synthetic Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Mantas Jonaitis
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, University of Edinburgh, Edinburgh, United Kingdom
| | - Flora Hewitt-Harris
- Centre for Engineering Biology, Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Megan Murdoch
- Centre for Engineering Biology, Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Susan Rosser
- UK Centre for Mammalian Synthetic Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - David C Hay
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, University of Edinburgh, Edinburgh, United Kingdom
| | - Lynne Regan
- Centre for Engineering Biology, Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom.
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4
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Zheng B, Xiao Y, Tong B, Mao Y, Ge R, Tian F, Dong X, Zheng P. S373P Mutation Stabilizes the Receptor-Binding Domain of the Spike Protein in Omicron and Promotes Binding. JACS AU 2023; 3:1902-1910. [PMID: 37502147 PMCID: PMC10369413 DOI: 10.1021/jacsau.3c00142] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 06/12/2023] [Accepted: 06/12/2023] [Indexed: 07/29/2023]
Abstract
A cluster of several newly occurring mutations on Omicron is found at the β-core region of the spike protein's receptor-binding domain (RBD), where mutation rarely happened before. Notably, the binding of SARS-CoV-2 to human receptor ACE2 via RBD happens in a dynamic airway environment, where mechanical force caused by coughing or sneezing occurs. Thus, we used atomic force microscopy-based single-molecule force spectroscopy (AFM-SMFS) to measure the stability of RBDs and found that the mechanical stability of Omicron RBD increased by ∼20% compared with the wild type. Molecular dynamics (MD) simulations revealed that Omicron RBD showed more hydrogen bonds in the β-core region due to the closing of the α-helical motif caused primarily by the S373P mutation. In addition to a higher unfolding force, we showed a higher dissociation force between Omicron RBD and ACE2. This work reveals the mechanically stabilizing effect of the conserved mutation S373P for Omicron and the possible evolution trend of the β-core region of RBD.
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Affiliation(s)
- Bin Zheng
- State
Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine
Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Yuelong Xiao
- State
Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine
Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Bei Tong
- Institute
of Botany, Jiangsu Province and Chinese
Academy of Sciences, Nanjing, Jiangsu 210014, China
| | - Yutong Mao
- State
Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine
Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Rui Ge
- State
Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine
Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Fang Tian
- State
Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine
Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Xianchi Dong
- State
Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210023, China
- Engineering
Research Center of Protein and Peptide Medicine, Ministry of Education, Nanjing, Jiangsu 210023, China
| | - Peng Zheng
- State
Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine
Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China
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5
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Boni R, Regan L. Modulating the Viscoelastic Properties of Covalently Crosslinked Protein Hydrogels. Gels 2023; 9:481. [PMID: 37367151 DOI: 10.3390/gels9060481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/22/2023] [Accepted: 06/09/2023] [Indexed: 06/28/2023] Open
Abstract
Protein engineering allows for the programming of specific building blocks to form functional and novel materials with customisable physical properties suitable for tailored engineering applications. We have successfully designed and programmed engineered proteins to form covalent molecular networks with defined physical characteristics. Our hydrogel design incorporates the SpyTag (ST) peptide and SpyCatcher (SC) protein that spontaneously form covalent crosslinks upon mixing. This genetically encodable chemistry allowed us to easily incorporate two stiff and rod-like recombinant proteins in the hydrogels and modulate the resulting viscoelastic properties. We demonstrated how differences in the composition of the microscopic building blocks change the macroscopic viscoelastic properties of the hydrogels. We specifically investigated how the identity of the protein pairs, the molar ratio of ST:SC, and the concentration of the proteins influence the viscoelastic response of the hydrogels. By showing tuneable changes in protein hydrogel rheology, we increased the capabilities of synthetic biology to create novel materials, allowing engineering biology to interface with soft matter, tissue engineering, and material science.
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Affiliation(s)
- Rossana Boni
- Centre for Engineering Biology, School of Biological Sciences, Institute of Quantitative Biology, Biochemistry and Biotechnology, University of Edinburgh, Edinburgh EH9 3FF, UK
| | - Lynne Regan
- Centre for Engineering Biology, School of Biological Sciences, Institute of Quantitative Biology, Biochemistry and Biotechnology, University of Edinburgh, Edinburgh EH9 3FF, UK
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6
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Collagen-like Motifs of SasG: A Novel Fold for Protein Mechanical Strength. J Mol Biol 2023; 435:167980. [PMID: 36708761 DOI: 10.1016/j.jmb.2023.167980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 01/11/2023] [Accepted: 01/19/2023] [Indexed: 01/26/2023]
Abstract
The Staphylococcus aureus surface protein G (SasG) is associated with host colonisation and biofilm formation. As colonisation occurs at the liquid-substrate interface bacteria are subject to a myriad of external forces and, presumably as a consequence, SasG displays extreme mechanical strength. This mechanical phenotype arises from the B-domain; a repetitive region composed of alternating E and G5 subdomains. These subdomains have an unusual structure comprising collagen-like regions capped by triple-stranded β-sheets. To identify the determinants of SasG mechanical strength, we characterised the mechanical phenotype and thermodynamic stability of 18 single substitution variants of a pseudo-wildtype protein. Visualising the mechanically-induced transition state at a residue-level by ϕ-value analysis reveals that the main force-bearing regions are the N- and C-terminal 'Mechanical Clamps' and their side-chain interactions. This is tailored by contacts at the pseudo-hydrophobic core interface. We also describe a novel mechanical motif - the collagen-like region and show that glycine to alanine substitutions, analogous to those found in Osteogenesis Imperfecta (brittle bone disease), result in a significantly reduced mechanical strength.
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7
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Clark LC, Atkin KE, Whelan F, Brentnall AS, Harris G, Towell AM, Turkenburg JP, Liu Y, Feizi T, Griffiths SC, Geoghegan JA, Potts JR. Staphylococcal Periscope proteins Aap, SasG, and Pls project noncanonical legume-like lectin adhesin domains from the bacterial surface. J Biol Chem 2023; 299:102936. [PMID: 36702253 PMCID: PMC9999234 DOI: 10.1016/j.jbc.2023.102936] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 01/08/2023] [Accepted: 01/18/2023] [Indexed: 01/25/2023] Open
Abstract
Staphylococcus aureus and Staphylococcus epidermidis are frequently associated with medical device infections that involve establishment of a bacterial biofilm on the device surface. Staphylococcal surface proteins Aap, SasG, and Pls are members of the Periscope Protein class and have been implicated in biofilm formation and host colonization; they comprise a repetitive region ("B region") and an N-terminal host colonization domain within the "A region," predicted to be a lectin domain. Repetitive E-G5 domains (as found in Aap, SasG, and Pls) form elongated "stalks" that would vary in length with repeat number, resulting in projection of the N-terminal A domain variable distances from the bacterial cell surface. Here, we present the structures of the lectin domains within A regions of SasG, Aap, and Pls and a structure of the Aap lectin domain attached to contiguous E-G5 repeats, suggesting the lectin domains will sit at the tip of the variable length rod. We demonstrate that these isolated domains (Aap, SasG) are sufficient to bind to human host desquamated nasal epithelial cells. Previously, proteolytic cleavage or a deletion within the A domain had been reported to induce biofilm formation; the structures suggest a potential link between these observations. Intriguingly, while the Aap, SasG, and Pls lectin domains bind a metal ion, they lack the nonproline cis peptide bond thought to be key for carbohydrate binding by the lectin fold. This suggestion of noncanonical ligand binding should be a key consideration when investigating the host cell interactions of these bacterial surface proteins.
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Affiliation(s)
- Laura C Clark
- Department of Biology, University of York, York, United Kingdom
| | - Kate E Atkin
- Department of Biology, University of York, York, United Kingdom
| | - Fiona Whelan
- Department of Biology, University of York, York, United Kingdom; Department of Molecular and Biomedical Science, School of Biological Sciences, University of Adelaide, South Australia, Australia.
| | | | - Gemma Harris
- Department of Biology, University of York, York, United Kingdom
| | - Aisling M Towell
- Department of Microbiology, Moyne Institute of Preventive Medicine, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland
| | | | - Yan Liu
- Glycosciences Laboratory, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Ten Feizi
- Glycosciences Laboratory, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London, United Kingdom
| | | | - Joan A Geoghegan
- Department of Microbiology, Moyne Institute of Preventive Medicine, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland; Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Jennifer R Potts
- Department of Biology, University of York, York, United Kingdom; School of Life and Environmental Sciences, University of Sydney, New South Wales, Australia.
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8
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Wang C, Chantraine C, Viljoen A, Herr AB, Fey PD, Horswill AR, Mathelié-Guinlet M, Dufrêne YF. The staphylococcal biofilm protein Aap mediates cell-cell adhesion through mechanically distinct homophilic and lectin interactions. PNAS NEXUS 2022; 1:pgac278. [PMID: 36712378 PMCID: PMC9802226 DOI: 10.1093/pnasnexus/pgac278] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Accepted: 12/01/2022] [Indexed: 12/04/2022]
Abstract
The accumulation phase of staphylococcal biofilms relies on both the production of an extracellular polysaccharide matrix and the expression of bacterial surface proteins. A prototypical example of such adhesive proteins is the long multidomain protein Aap (accumulation-associated protein) from Staphylococcus epidermidis, which mediates zinc-dependent homophilic interactions between Aap B-repeat regions through molecular forces that have not been investigated yet. Here, we unravel the remarkable mechanical strength of single Aap-Aap homophilic bonds between living bacteria and we demonstrate that intercellular adhesion also involves sugar binding through the lectin domain of the Aap A region. We find that the mechanical force needed to unfold individual β-sheet-rich G5-E domains from the Aap B-repeat regions is very high, ranging from 300 up to 1,000 pN at high loading rates, indicating these are extremely stable. This high mechanostability provides a means to the cells to form highly adhesive and cohesive biofilms capable of sustaining high physiological shear stress. Importantly, we identify a previously undescribed role of Aap in bacterial-bacterial adhesion, that is, heterophilic sugar binding by a specific lectin domain located in the N-terminal A region, which might be important to establish initial contacts between cells before strong homophilic bonds come into play. This study emphasizes the remarkable mechanical and binding properties of Aap as well as its wide diversity of adhesive functions.
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Affiliation(s)
| | | | - Albertus Viljoen
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium
| | - Andrew B Herr
- Divisions of Immunobiology and Infectious Diseases, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Paul D Fey
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Alexander R Horswill
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO 80045, USA
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9
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The long and the short of Periscope Proteins. Biochem Soc Trans 2022; 50:1293-1302. [PMID: 36196877 DOI: 10.1042/bst20220194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 09/10/2022] [Accepted: 09/13/2022] [Indexed: 11/17/2022]
Abstract
Bacteria sense, interact with, and modify their environmental niche by deploying a molecular ensemble at the cell surface. The changeability of this exposed interface, combined with extreme changes in the functional repertoire associated with lifestyle switches from planktonic to adherent and biofilm states necessitate dynamic variability. Dynamic surface changes include chemical modifications to the cell wall; export of diverse extracellular biofilm components; and modulation of expression of cell surface proteins for adhesion, co-aggregation and virulence. Local enrichment for highly repetitive proteins with high tandem repeat identity has been an enigmatic phenomenon observed in diverse bacterial species. Preliminary observations over decades of research suggested these repeat regions were hypervariable, as highly related strains appeared to express homologues with diverse molecular mass. Long-read sequencing data have been interrogated to reveal variation in repeat number; in combination with structural, biophysical and molecular dynamics approaches, the Periscope Protein class has been defined for cell surface attached proteins that dynamically expand and contract tandem repeat tracts at the population level. Here, I review the diverse high-stability protein folds and coherent interdomain linkages culminating in the formation of highly anisotropic linear repeat arrays, so-called rod-like protein 'stalks', supporting roles in bacterial adhesion, biofilm formation, cell surface spatial competition, and immune system modulation. An understanding of the functional impacts of dynamic changes in repeat arrays and broader characterisation of the unusual protein folds underpinning this variability will help with the design of immunisation strategies, and contribute to synthetic biology approaches including protein engineering and microbial consortia construction.
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10
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Yarawsky AE, Hopkins JB, Chatzimagas L, Hub JS, Herr AB. Solution Structural Studies of Pre-amyloid Oligomer States of the Biofilm Protein Aap. J Mol Biol 2022; 434:167708. [PMID: 35777467 PMCID: PMC9615840 DOI: 10.1016/j.jmb.2022.167708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/20/2022] [Accepted: 06/25/2022] [Indexed: 11/16/2022]
Abstract
Staphylococcus epidermidis is a commensal bacterium on human skin that is also the leading cause of medical device-related infections. The accumulation-associated protein (Aap) from S. epidermidis is a critical factor for infection via its ability to mediate biofilm formation. The B-repeat superdomain of Aap is composed of 5 to 17 Zn2+-binding B-repeats, which undergo rapid, reversible assembly to form dimer and tetramer species. The tetramer can then undergo a conformational change and nucleate highly stable functional amyloid fibrils. In this study, multiple techniques including analytical ultracentrifugation (AUC) and small-angle X-ray scattering (SAXS) are used to probe a panel of B-repeat mutant constructs that assemble to distinct oligomeric states to define the structural characteristics of B-repeat dimer and tetramer species. The B-repeat region from Aap forms an extremely elongated conformation that presents several challenges for standard SAXS analyses. Specialized approaches, such as cross-sectional analyses, allowed for in-depth interpretation of data, while explicit-solvent calculations via WAXSiS allowed for accurate evaluation of atomistic models. The resulting models suggest mechanisms by which Aap functional amyloid fibrils form, illuminating an important contributing factor to recurrent staphylococcal infections.
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Affiliation(s)
- Alexander E Yarawsky
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Jesse B Hopkins
- The Biophysics Collaborative Access Team (BioCAT), Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL, USA
| | - Leonie Chatzimagas
- Theoretical Physics and Center for Biophysics, Saarland University, Saarbrücken, Germany
| | - Jochen S Hub
- Theoretical Physics and Center for Biophysics, Saarland University, Saarbrücken, Germany
| | - Andrew B Herr
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Division of Infectious Diseases, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
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11
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Ma Z, Zhu K, Gao Y, Tan S, Miao Y. Molecular condensation and mechanoregulation of plant class I formin, an integrin‐like actin nucleator. FEBS J 2022. [DOI: 10.1111/febs.16571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 05/29/2022] [Accepted: 07/04/2022] [Indexed: 11/30/2022]
Affiliation(s)
- Zhiming Ma
- School of Biological Sciences Nanyang Technological University Singapore City Singapore
| | - Kexin Zhu
- School of Biological Sciences Nanyang Technological University Singapore City Singapore
| | - Yong‐Gui Gao
- School of Biological Sciences Nanyang Technological University Singapore City Singapore
| | - Suet‐Mien Tan
- School of Biological Sciences Nanyang Technological University Singapore City Singapore
| | - Yansong Miao
- School of Biological Sciences Nanyang Technological University Singapore City Singapore
- Institute for Digital Molecular Analytics and Science Nanyang Technological University Singapore City Singapore
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12
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On the Effects of Disordered Tails, Supertertiary Structure and Quinary Interactions on the Folding and Function of Protein Domains. Biomolecules 2022; 12:biom12020209. [PMID: 35204709 PMCID: PMC8961636 DOI: 10.3390/biom12020209] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/17/2022] [Accepted: 01/22/2022] [Indexed: 11/17/2022] Open
Abstract
The vast majority of our current knowledge about the biochemical and biophysical properties of proteins derives from in vitro studies conducted on isolated globular domains. However, a very large fraction of the proteins expressed in the eukaryotic cell are structurally more complex. In particular, the discovery that up to 40% of the eukaryotic proteins are intrinsically disordered, or possess intrinsically disordered regions, and are highly dynamic entities lacking a well-defined three-dimensional structure, revolutionized the structure–function paradigm and our understanding of proteins. Moreover, proteins are mostly characterized by the presence of multiple domains, influencing each other by intramolecular interactions. Furthermore, proteins exert their function in a crowded intracellular milieu, transiently interacting with a myriad of other macromolecules. In this review we summarize the literature tackling these themes from both the theoretical and experimental perspectives, highlighting the effects on protein folding and function that are played by (i) flanking disordered tails; (ii) contiguous protein domains; (iii) interactions with the cellular environment, defined as quinary structures. We show that, in many cases, both the folding and function of protein domains is remarkably perturbed by the presence of these interactions, pinpointing the importance to increase the level of complexity of the experimental work and to extend the efforts to characterize protein domains in more complex contexts.
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13
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Chantraine C, Mathelié-Guinlet M, Pietrocola G, Speziale P, Dufrêne YF. AFM Identifies a Protein Complex Involved in Pathogen Adhesion Which Ruptures at Three Nanonewtons. NANO LETTERS 2021; 21:7595-7601. [PMID: 34469164 DOI: 10.1021/acs.nanolett.1c02105] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Staphylococci bind to the blood protein von Willebrand Factor (vWF), thereby causing endovascular infections. Whether and how this interaction occurs with the medically important pathogen Staphylococcus epidermidis is unknown. Using single-molecule experiments, we demonstrate that the S. epidermidis protein Aap binds vWF via an ultrastrong force, ∼3 nN, the strongest noncovalent biological bond ever reported, and we show that this interaction is activated by tensile loading, suggesting a catch-bond behavior. Aap-vWF binding involves exclusively the A1 domain of vWF but requires both the A and B domains of Aap, as revealed by inhibition assays using specific monoclonal antibodies. Collectively, our results point to a mechanism where force-induced unfolding of the B repeats activates the A domain of Aap, shifting it from a weak- to a strong-binding state, which then engages into an ultrastrong interaction with vWF A1. This shear-dependent function of Aap offers promise for innovative antistaphylococcal therapies.
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Affiliation(s)
- Constance Chantraine
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium
| | - Marion Mathelié-Guinlet
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium
| | - Giampiero Pietrocola
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Viale Taramelli 3/b, 27100 Pavia, Italy
| | - Pietro Speziale
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Viale Taramelli 3/b, 27100 Pavia, Italy
| | - Yves F Dufrêne
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium
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14
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Periscope Proteins are variable-length regulators of bacterial cell surface interactions. Proc Natl Acad Sci U S A 2021; 118:2101349118. [PMID: 34074781 PMCID: PMC8201768 DOI: 10.1073/pnas.2101349118] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The structure of single and tandem SHIRT domains from the streptococcal surface protein Sgo_0707 were determined. In conjunction with biophysics and molecular dynamics simulations, the results show that the observed gene length variation would result in differential projection of the host ligand binding domain on the bacterial cell surface. An analysis of long-read DNA sequence data reveals many other repetitive bacterial surface proteins that appear to undergo gene length variation. We propose that these variable-length “Periscope Proteins” represent an important mechanism of bacterial cell surface modification with potential roles in infection and immune evasion. Changes at the cell surface enable bacteria to survive in dynamic environments, such as diverse niches of the human host. Here, we reveal “Periscope Proteins” as a widespread mechanism of bacterial surface alteration mediated through protein length variation. Tandem arrays of highly similar folded domains can form an elongated rod-like structure; thus, variation in the number of domains determines how far an N-terminal host ligand binding domain projects from the cell surface. Supported by newly available long-read genome sequencing data, we propose that this class could contain over 50 distinct proteins, including those implicated in host colonization and biofilm formation by human pathogens. In large multidomain proteins, sequence divergence between adjacent domains appears to reduce interdomain misfolding. Periscope Proteins break this “rule,” suggesting that their length variability plays an important role in regulating bacterial interactions with host surfaces, other bacteria, and the immune system.
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15
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Maikranz E, Spengler C, Thewes N, Thewes A, Nolle F, Jung P, Bischoff M, Santen L, Jacobs K. Different binding mechanisms of Staphylococcus aureus to hydrophobic and hydrophilic surfaces. NANOSCALE 2020; 12:19267-19275. [PMID: 32935690 DOI: 10.1039/d0nr03134h] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Bacterial adhesion to surfaces is a crucial step in initial biofilm formation. In a combined experimental and computational approach, we studied the adhesion of the pathogenic bacterium Staphylococcus aureus to hydrophilic and hydrophobic surfaces. We used atomic force microscopy-based single-cell force spectroscopy and Monte Carlo simulations to investigate the similarities and differences of adhesion to hydrophilic and hydrophobic surfaces. Our results reveal that binding to both types of surfaces is mediated by thermally fluctuating cell wall macromolecules that behave differently on each type of substrate: on hydrophobic surfaces, many macromolecules are involved in adhesion, yet only weakly tethered, leading to high variance between individual bacteria, but low variance between repetitions with the same bacterium. On hydrophilic surfaces, however, only few macromolecules tether strongly to the surface. Since during every repetition with the same bacterium different macromolecules bind, we observe a comparable variance between repetitions and different bacteria. We expect these findings to be of importance for the understanding of the adhesion behaviour of many bacterial species as well as other microorganisms and even nanoparticles with soft, macromolecular coatings, used e.g. for biological diagnostics.
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Affiliation(s)
- Erik Maikranz
- Theoretical Physics, Saarland University, Center for Biophysics, 66123 Saarbrücken, Germany.
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16
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Acetylation of Surface Carbohydrates in Bacterial Pathogens Requires Coordinated Action of a Two-Domain Membrane-Bound Acyltransferase. mBio 2020; 11:mBio.01364-20. [PMID: 32843546 PMCID: PMC7448272 DOI: 10.1128/mbio.01364-20] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Acyltransferase-3 (AT3) domain-containing membrane proteins are involved in O-acetylation of a diverse range of carbohydrates across all domains of life. In bacteria they are essential in processes including symbiosis, resistance to antimicrobials, and biosynthesis of antibiotics. Their mechanism of action, however, is poorly characterized. We analyzed two acetyltransferases as models for this important family of membrane proteins, which modify carbohydrates on the surface of the pathogen Salmonella enterica, affecting immunogenicity, virulence, and bacteriophage resistance. We show that when these AT3 domains are fused to a periplasmic partner domain, both domains are required for substrate acetylation. The data show conserved elements in the AT3 domain and unique structural features of the periplasmic domain. Our data provide a working model to probe the mechanism and function of the diverse and important members of the widespread AT3 protein family, which are required for biologically significant modifications of cell-surface carbohydrates. Membrane bound acyltransferase-3 (AT3) domain-containing proteins are implicated in a wide range of carbohydrate O-acyl modifications, but their mechanism of action is largely unknown. O-antigen acetylation by AT3 domain-containing acetyltransferases of Salmonella spp. can generate a specific immune response upon infection and can influence bacteriophage interactions. This study integrates in situ and in vitro functional analyses of two of these proteins, OafA and OafB (formerly F2GtrC), which display an “AT3-SGNH fused” domain architecture, where an integral membrane AT3 domain is fused to an extracytoplasmic SGNH domain. An in silico-inspired mutagenesis approach of the AT3 domain identified seven residues which are fundamental for the mechanism of action of OafA, with a particularly conserved motif in TMH1 indicating a potential acyl donor interaction site. Genetic and in vitro evidence demonstrate that the SGNH domain is both necessary and sufficient for lipopolysaccharide acetylation. The structure of the periplasmic SGNH domain of OafB identified features not previously reported for SGNH proteins. In particular, the periplasmic portion of the interdomain linking region is structured. Significantly, this region constrains acceptor substrate specificity, apparently by limiting access to the active site. Coevolution analysis of the two domains suggests possible interdomain interactions. Combining these data, we propose a refined model of the AT3-SGNH proteins, with structurally constrained orientations of the two domains. These findings enhance our understanding of how cells can transfer acyl groups from the cytoplasm to specific extracellular carbohydrates.
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17
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Foster TJ. Surface Proteins of Staphylococcus epidermidis. Front Microbiol 2020; 11:1829. [PMID: 32849430 PMCID: PMC7403478 DOI: 10.3389/fmicb.2020.01829] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 07/13/2020] [Indexed: 01/06/2023] Open
Abstract
Staphylococcus epidermidis is a ubiquitous commensal of human skin. The widespread use of indwelling medical devices in modern medicine provides an opportunity for it to cause infections. Disease causing isolates can come from many different genetic backgrounds. Multiply antibiotic resistant strains have spread globally. S. epidermidis has a smaller repertoire of cell wall anchored (CWA) surface proteins than Staphylococcus aureus. Nevertheless, these CWA proteins promote adhesion to components of the extracellular matrix including collagen, fibrinogen, and fibronectin and contribute to the formation of biofilm. The A domain of the accumulation associated protein Aap can promote adhesion to unconditioned biomaterial but must be removed proteolytically to allow accumulation to proceed by homophilic Zn2+-dependent interactions. Mature biofilm contains amyloid structures formed by Aap and the small basic protein (Sbp). The latter contributes to the integrity of both protein and polysaccharide biofilm matrices. Several other CWA proteins can also promote S. epidermidis biofilm formation.
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Affiliation(s)
- Timothy J Foster
- Department of Microbiology, Trinity College Dublin, Dublin, Ireland
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18
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Jasaitis L, Silver CD, Rawlings AE, Peters DT, Whelan F, Regan L, Pasquina-Lemonche L, Potts JR, Johnson SD, Staniland SS. Rational Design and Self-Assembly of Coiled-Coil Linked SasG Protein Fibrils. ACS Synth Biol 2020; 9:1599-1607. [PMID: 32551507 DOI: 10.1021/acssynbio.0c00156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Protein engineering is an attractive approach for the self-assembly of nanometer-scale architectures for a range of potential nanotechnologies. Using the versatile chemistry provided by protein folding and assembly, coupled with amino acid side-chain functionality, allows for the construction of precise molecular "protein origami" hierarchical patterned structures for a range of nanoapplications such as stand-alone enzymatic pathways and molecular machines. The Staphyloccocus aureus surface protein SasG is a rigid, rod-like structure shown to have high mechanical strength due to "clamp-like" intradomain features and a stabilizing interface between the G5 and E domains, making it an excellent building block for molecular self-assembly. Here we characterize a new two subunit system composed of the SasG rod protein genetically conjugated with de novo designed coiled-coils, resulting in the self-assembly of fibrils. Circular dichroism (CD) and quartz-crystal microbalance with dissipation (QCM-D) are used to show the specific, alternating binding between the two subunits. Furthermore, we use atomic force microscopy (AFM) to study the extent of subunit polymerization in a liquid environment, demonstrating self-assembly culminating in the formation of linear macromolecular fibrils.
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Affiliation(s)
- Lukas Jasaitis
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom
| | - Callum D. Silver
- Department of Electronic Engineering, University of York, York YO10 5DD, United Kingdom
| | - Andrea E. Rawlings
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom
| | - Daniel T. Peters
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Fiona Whelan
- School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Lynne Regan
- Institute for Quantitative Biology, Biochemistry and Biotechnology, University of Edinburgh, Edinburgh EH9 3JU, Scotland
| | - Laia Pasquina-Lemonche
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7HF, United Kingdom
| | - Jennifer R. Potts
- School of Life and Environmental Science, University of Sydney, Sydney, NSW 2006, Australia
- Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Steven D. Johnson
- Department of Electronic Engineering, University of York, York YO10 5DD, United Kingdom
| | - Sarah S. Staniland
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom
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19
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Dufrêne YF, Viljoen A. Binding Strength of Gram-Positive Bacterial Adhesins. Front Microbiol 2020; 11:1457. [PMID: 32670256 PMCID: PMC7330015 DOI: 10.3389/fmicb.2020.01457] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 06/04/2020] [Indexed: 11/13/2022] Open
Abstract
Bacterial pathogens are equipped with specialized surface-exposed proteins that bind strongly to ligands on host tissues and biomaterials. These adhesins play critical roles during infection, especially during the early step of adhesion where the cells are exposed to physical stress. Recent single-molecule experiments have shown that staphylococci interact with their ligands through a wide diversity of mechanosensitive molecular mechanisms. Adhesin-ligand interactions are activated by tensile force and can be ten times stronger than classical non-covalent biological bonds. Overall these studies demonstrate that Gram-positive adhesins feature unusual stress-dependent molecular interactions, which play essential roles during bacterial colonization and dissemination. With an increasing prevalence of multidrug resistant infections caused by Staphylococcus aureus and Staphylococcus epidermidis, chemotherapeutic targeting of adhesins offers an innovative alternative to antibiotics.
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Affiliation(s)
- Yves F Dufrêne
- Louvain Institute of Biomolecular Science and Technology, Catholic University of Louvain, Louvain-la-Neuve, Belgium
| | - Albertus Viljoen
- Louvain Institute of Biomolecular Science and Technology, Catholic University of Louvain, Louvain-la-Neuve, Belgium
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20
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Back CR, Higman VA, Le Vay K, Patel VV, Parnell AE, Frankel D, Jenkinson HF, Burston SG, Crump MP, Nobbs AH, Race PR. The streptococcal multidomain fibrillar adhesin CshA has an elongated polymeric architecture. J Biol Chem 2020; 295:6689-6699. [PMID: 32229583 PMCID: PMC7212634 DOI: 10.1074/jbc.ra119.011719] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 03/26/2020] [Indexed: 11/06/2022] Open
Abstract
The cell surfaces of many bacteria carry filamentous polypeptides termed adhesins that enable binding to both biotic and abiotic surfaces. Surface adherence is facilitated by the exquisite selectivity of the adhesins for their cognate ligands or receptors and is a key step in niche or host colonization and pathogenicity. Streptococcus gordonii is a primary colonizer of the human oral cavity and an opportunistic pathogen, as well as a leading cause of infective endocarditis in humans. The fibrillar adhesin CshA is an important determinant of S. gordonii adherence, forming peritrichous fibrils on its surface that bind host cells and other microorganisms. CshA possesses a distinctive multidomain architecture comprising an N-terminal target-binding region fused to 17 repeat domains (RDs) that are each ∼100 amino acids long. Here, using structural and biophysical methods, we demonstrate that the intact CshA repeat region (CshA_RD1-17, domains 1-17) forms an extended polymeric monomer in solution. We recombinantly produced a subset of CshA RDs and found that they differ in stability and unfolding behavior. The NMR structure of CshA_RD13 revealed a hitherto unreported all β-fold, flanked by disordered interdomain linkers. These findings, in tandem with complementary hydrodynamic studies of CshA_RD1-17, indicate that this polypeptide possesses a highly unusual dynamic transitory structure characterized by alternating regions of order and disorder. This architecture provides flexibility for the adhesive tip of the CshA fibril to maintain bacterial attachment that withstands shear forces within the human host. It may also help mitigate deleterious folding events between neighboring RDs that share significant structural identity without compromising mechanical stability.
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Affiliation(s)
- Catherine R Back
- Bristol Dental School, University of Bristol, Bristol BS1 2LY, United Kingdom
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
- BrisSynBio Synthetic Biology Research Centre, University of Bristol, Bristol BS8 1TQ, United Kingdom
| | - Victoria A Higman
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Kristian Le Vay
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
- Bristol Centre for Functional Nanomaterials, H. H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, United Kingdom
| | - Viren V Patel
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Alice E Parnell
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
- BrisSynBio Synthetic Biology Research Centre, University of Bristol, Bristol BS8 1TQ, United Kingdom
| | - Daniel Frankel
- School of Engineering, Newcastle University, Newcastle-upon-Tyne NE1 7RU, United Kingdom
| | - Howard F Jenkinson
- Bristol Dental School, University of Bristol, Bristol BS1 2LY, United Kingdom
| | - Steven G Burston
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
- BrisSynBio Synthetic Biology Research Centre, University of Bristol, Bristol BS8 1TQ, United Kingdom
| | - Matthew P Crump
- BrisSynBio Synthetic Biology Research Centre, University of Bristol, Bristol BS8 1TQ, United Kingdom
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Angela H Nobbs
- Bristol Dental School, University of Bristol, Bristol BS1 2LY, United Kingdom
| | - Paul R Race
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
- BrisSynBio Synthetic Biology Research Centre, University of Bristol, Bristol BS8 1TQ, United Kingdom
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21
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Pinto F, Thornton EL, Wang B. An expanded library of orthogonal split inteins enables modular multi-peptide assemblies. Nat Commun 2020; 11:1529. [PMID: 32251274 PMCID: PMC7090010 DOI: 10.1038/s41467-020-15272-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 02/26/2020] [Indexed: 01/03/2023] Open
Abstract
Inteins are protein segments capable of joining adjacent residues via a peptide bond. In this process known as protein splicing, the intein itself is not present in the final sequence, thus achieving scarless peptide ligation. Here, we assess the splicing activity of 34 inteins (both uncharacterized and known) using a rapid split fluorescent reporter characterization platform, and establish a library of 15 mutually orthogonal split inteins for in vivo applications, 10 of which can be simultaneously used in vitro. We show that orthogonal split inteins can be coupled to multiple split transcription factors to implement complex logic circuits in living organisms, and that they can also be used for the in vitro seamless assembly of large repetitive proteins with biotechnological relevance. Our work demonstrates the versatility and vast potential of an expanded library of orthogonal split inteins for their use in the fields of synthetic biology and protein engineering.
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Affiliation(s)
- Filipe Pinto
- School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FF, UK
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3FF, UK
| | - Ella Lucille Thornton
- School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FF, UK
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3FF, UK
| | - Baojun Wang
- School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FF, UK.
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3FF, UK.
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22
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Gräwert TW, Svergun DI. Structural Modeling Using Solution Small-Angle X-ray Scattering (SAXS). J Mol Biol 2020; 432:3078-3092. [PMID: 32035901 DOI: 10.1016/j.jmb.2020.01.030] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 01/21/2020] [Accepted: 01/21/2020] [Indexed: 01/01/2023]
Abstract
Small-angle X-ray scattering (SAXS) offers a way to examine the overall shape and oligomerization state of biological macromolecules under quasi native conditions in solution. In the past decades, SAXS has become a standard tool for structure biologists due to the availability of high brilliance X-ray sources and the development of data analysis/interpretation methods. Sample handling robots and software pipelines have significantly reduced the time necessary to conduct SAXS experiments. Presently, most synchrotrons feature beamlines dedicated to biological SAXS, and the SAXS-derived models are deposited into dedicated and accessible databases. The size of macromolecules that may be analyzed ranges from small peptides or snippets of nucleic acids to gigadalton large complexes or even entire viruses. Compared to other structural methods, sample preparation is straightforward, and the risk of inducing preparation artefacts is minimal. Very importantly, SAXS is a method of choice to study flexible systems like unfolded or disordered proteins, providing the structural ensembles compatible with the data. Although it may be utilized stand-alone, SAXS profits a lot from available experimental or predicted high-resolution data and information from complementary biophysical methods. Here, we show the basic principles of SAXS and review latest developments in the fields of hybrid modeling and flexible systems.
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Affiliation(s)
- Tobias W Gräwert
- Hamburg Outstation, European Molecular Biology Laboratory, Notkestrasse 85, 22607 Hamburg, Germany.
| | - Dmitri I Svergun
- Hamburg Outstation, European Molecular Biology Laboratory, Notkestrasse 85, 22607 Hamburg, Germany.
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23
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Viela F, Mathelié-Guinlet M, Viljoen A, Dufrêne YF. What makes bacterial pathogens so sticky? Mol Microbiol 2020; 113:683-690. [PMID: 31916325 DOI: 10.1111/mmi.14448] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/06/2020] [Indexed: 01/06/2023]
Abstract
Pathogenic bacteria use a variety of cell surface adhesins to promote binding to host tissues and protein-coated biomaterials, as well as cell-cell aggregation. These cellular interactions represent the first essential step that leads to host colonization and infection. Atomic force microscopy (AFM) has greatly contributed to increase our understanding of the specific interactions at play during microbial adhesion, down to the single-molecule level. A key asset of AFM is that adhesive interactions are studied under mechanical force, which is highly relevant as surface-attached pathogens are often exposed to physical stresses in the human body. These studies have identified sophisticated binding mechanisms in adhesins, which represent promising new targets for antiadhesion therapy.
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Affiliation(s)
- Felipe Viela
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium
| | - Marion Mathelié-Guinlet
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium
| | - Albertus Viljoen
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium
| | - Yves F Dufrêne
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium.,Walloon Excellence in Life sciences and Biotechnology (WELBIO), Wavre, Belgium
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24
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Yuan G, Ma Q, Wu T, Wang M, Li X, Zuo J, Zheng P. Multistep Protein Unfolding Scenarios from the Rupture of a Complex Metal Cluster Cd 3S 9. Sci Rep 2019; 9:10518. [PMID: 31324867 PMCID: PMC6642161 DOI: 10.1038/s41598-019-47004-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 07/04/2019] [Indexed: 12/14/2022] Open
Abstract
Protein (un)folding is a complex and essential process. With the rapid development of single-molecule techniques, we can detect multiple and transient proteins (un)folding pathways/intermediates. However, the observation of multiple multistep (>2) unfolding scenarios for a single protein domain remains limited. Here, we chose metalloprotein with relatively stable and multiple metal-ligand coordination bonds as a system for such a purpose. Using AFM-based single-molecule force spectroscopy (SMFS), we successfully demonstrated the complex and multistep protein unfolding scenarios of the β-domain of a human protein metallothionein-3 (MT). MT is a protein of ~60 amino acids (aa) in length with 20 cysteines for various metal binding, and the β-domain (βMT) is of ~30 aa with an M3S9 metal cluster. We detected four different types of three-step protein unfolding scenarios from the Cd-βMT, which can be possibly explained by the rupture of Cd-S bonds in the complex Cd3S9 metal cluster. In addition, complex unfolding scenarios with four rupture peaks were observed. The Cd-S bonds ruptured in both single bond and multiple bonds modes. Our results provide not only evidence for multistep protein unfolding phenomena but also reveal unique properties of metalloprotein system using single-molecule AFM.
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Affiliation(s)
- Guodong Yuan
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 21002, China
| | - Qun Ma
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 21002, China
| | - Tao Wu
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 21002, China
| | - Mengdi Wang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 21002, China
| | - Xi Li
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 21002, China
| | - Jinglin Zuo
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 21002, China
| | - Peng Zheng
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 21002, China.
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25
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Foster TJ. Surface Proteins of Staphylococcus aureus. Microbiol Spectr 2019; 7:10.1128/microbiolspec.gpp3-0046-2018. [PMID: 31267926 PMCID: PMC10957221 DOI: 10.1128/microbiolspec.gpp3-0046-2018] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Indexed: 12/20/2022] Open
Abstract
The surface of Staphylococcus aureus is decorated with over 20 proteins that are covalently anchored to peptidoglycan by the action of sortase A. These cell wall-anchored (CWA) proteins can be classified into several structural and functional groups. The largest is the MSCRAMM family, which is characterized by tandemly repeated IgG-like folded domains that bind peptide ligands by the dock lock latch mechanism or the collagen triple helix by the collagen hug. Several CWA proteins comprise modules that have different functions, and some individual domains can bind different ligands, sometimes by different mechanisms. For example, the N-terminus of the fibronectin binding proteins comprises an MSCRAMM domain which binds several ligands, while the C-terminus is composed of tandem fibronectin binding repeats. Surface proteins promote adhesion to host cells and tissue, including components of the extracellular matrix, contribute to biofilm formation by stimulating attachment to the host or indwelling medical devices followed by cell-cell accumulation via homophilic interactions between proteins on neighboring cells, help bacteria evade host innate immune responses, participate in iron acquisition from host hemoglobin, and trigger invasion of bacteria into cells that are not normally phagocytic. The study of genetically manipulated strains using animal infection models has shown that many CWA proteins contribute to pathogenesis. Fragments of CWA proteins have the potential to be used in multicomponent vaccines to prevent S. aureus infections.
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Abstract
Staphylococci, with the leading species Staphylococcus aureus and Staphylococcus epidermidis, are the most frequent causes of infections on indwelling medical devices. The biofilm phenotype that those bacteria adopt during device-associated infection facilitates increased resistance to antibiotics and host immune defenses. This review presents and discusses the molecular mechanisms contributing to staphylococcal biofilm development and their in-vivo importance. Furthermore, it summarizes current strategies for the development of therapeutics against staphylococcal biofilm-associated infection.
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Piiadov V, Ares de Araújo E, Oliveira Neto M, Craievich AF, Polikarpov I. SAXSMoW 2.0: Online calculator of the molecular weight of proteins in dilute solution from experimental SAXS data measured on a relative scale. Protein Sci 2018; 28:454-463. [PMID: 30371978 DOI: 10.1002/pro.3528] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 10/05/2018] [Accepted: 10/08/2018] [Indexed: 11/07/2022]
Abstract
Knowledge of molecular weight, oligomeric states, and quaternary arrangements of proteins in solution is fundamental for understanding their molecular functions and activities. We describe here a program SAXSMoW 2.0 for robust and quick determination of molecular weight and oligomeric state of proteins in dilute solution, starting from a single experimental small-angle scattering intensity curve, I(q), measured on a relative scale. The first version of this calculator has been widely used during the last decade and applied to analyze experimental SAXS data of many proteins and protein complexes. SAXSMoW 2.0 exhibits new features which allow for the direct input of experimental intensity curves and also automatic modes for quick determinations of the radius of gyration, volume, and molecular weight. The new program was extensively tested by applying it to many experimental SAXS curves downloaded from the open databases, corresponding to proteins with different shapes and molecular weights ranging from ~10 kDa up to about ~500 kDa and different shapes from globular to elongated. These tests reveal that the use of SAXSMoW 2.0 allows for determinations of molecular weights of proteins in dilute solution with a median discrepancy of about 12% for globular proteins. In case of elongated molecules, discrepancy value can be significantly higher. Our tests show discrepancies of approximately 21% for the proteins with molecular shape aspect ratios up to 18.
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Affiliation(s)
- Vassili Piiadov
- Institute of Physics of São Carlos, University of São Paulo, São Carlos, São Paulo, Brazil
| | - Evandro Ares de Araújo
- Institute of Physics of São Carlos, University of São Paulo, São Carlos, São Paulo, Brazil
| | - Mario Oliveira Neto
- Institute of Biosciences, University Estadual Paulista, Botucatu, São Paulo, Brazil
| | | | - Igor Polikarpov
- Institute of Physics of São Carlos, University of São Paulo, São Carlos, São Paulo, Brazil
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28
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Measuring Nanometer Distances Between Fluorescent Labels Step-by-Step. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2017; 1663:189-203. [PMID: 28924669 DOI: 10.1007/978-1-4939-7265-4_16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Super-resolution fluorescence microscopy methods are increasingly applied to study the structure of biological molecules within their natural context or at biomaterial interfaces. We here provide a protocol for Single-molecule High-Resolution Imaging with Photobleaching (SHRImP) that can be used to obtain information about the conformation of large proteins or other macromolecules at the single-molecule level. This procedure requires site-specific protein labeling with fluorescent dyes, immobilization and sample preparation, optimization of imaging buffer composition and microscope settings, and acquisition of short time-lapse movies that capture the stepwise bleaching behavior of individual molecules. We then describe a method for reliably determining the relative positions of labels from bleaching movies using the free image processing package Fiji (ImageJ) with the help of auxiliary macros that are provided as Supplementary Material. The presented approach allows for measuring intramolecular distance distributions in the range of a few to hundreds of nanometers and can be applied to a wide variety of biological systems.
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29
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Devine PWA, Fisher HC, Calabrese AN, Whelan F, Higazi DR, Potts JR, Lowe DC, Radford SE, Ashcroft AE. Investigating the Structural Compaction of Biomolecules Upon Transition to the Gas-Phase Using ESI-TWIMS-MS. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:1855-1862. [PMID: 28484973 PMCID: PMC5556138 DOI: 10.1007/s13361-017-1689-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 04/07/2017] [Accepted: 04/13/2017] [Indexed: 05/11/2023]
Abstract
Collision cross-section (CCS) measurements obtained from ion mobility spectrometry-mass spectrometry (IMS-MS) analyses often provide useful information concerning a protein's size and shape and can be complemented by modeling procedures. However, there have been some concerns about the extent to which certain proteins maintain a native-like conformation during the gas-phase analysis, especially proteins with dynamic or extended regions. Here we have measured the CCSs of a range of biomolecules including non-globular proteins and RNAs of different sequence, size, and stability. Using traveling wave IMS-MS, we show that for the proteins studied, the measured CCS deviates significantly from predicted CCS values based upon currently available structures. The results presented indicate that these proteins collapse to different extents varying on their elongated structures upon transition into the gas-phase. Comparing two RNAs of similar mass but different solution structures, we show that these biomolecules may also be susceptible to gas-phase compaction. Together, the results suggest that caution is needed when predicting structural models based on CCS data for RNAs as well as proteins with non-globular folds. Graphical Abstract ᅟ.
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Affiliation(s)
- Paul W A Devine
- Astbury Center for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Henry C Fisher
- Astbury Center for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Antonio N Calabrese
- Astbury Center for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Fiona Whelan
- Department of Biology, University of York, York, YO10 5DD, UK
| | - Daniel R Higazi
- Ipsen Ltd. UK, Wrexham Industrial Estate, 9 Ash Road North, Wrexham, LL13 9UF, UK
| | | | - David C Lowe
- MedImmune, Sir Aaron Klug Building, Granta Science Park, Cambridge, CB21 6GH, UK
| | - Sheena E Radford
- Astbury Center for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Alison E Ashcroft
- Astbury Center for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK.
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30
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Abstract
Numerous biological proteins exhibit intrinsic disorder at their termini, which are associated with multifarious functional roles. Here, we show the surprising result that an increased percentage of terminal short transiently disordered regions with enhanced flexibility (TstDREF) is associated with accelerated folding rates of globular proteins. Evolutionary conservation of predicted disorder at TstDREFs and drastic alteration of folding rates upon point-mutations suggest critical regulatory role(s) of TstDREFs in shaping the folding kinetics. TstDREFs are associated with long-range intramolecular interactions and the percentage of native secondary structural elements physically contacted by TstDREFs exhibit another surprising positive correlation with folding kinetics. These results allow us to infer probable molecular mechanisms behind the TstDREF-mediated regulation of folding kinetics that challenge protein biochemists to assess by direct experimental testing.
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Affiliation(s)
- Saurav Mallik
- Department of Biophysics, Molecular Biology and Bioinformatics, University of Calcutta, India.,Center of Excellence in Systems Biology and Biomedical Engineering (TEQIP Phase-II), University of Calcutta, India
| | - Tanaya Ray
- Harish-Chandra Research Institute, HBNI, Allahabad, India
| | - Sudip Kundu
- Department of Biophysics, Molecular Biology and Bioinformatics, University of Calcutta, India.,Center of Excellence in Systems Biology and Biomedical Engineering (TEQIP Phase-II), University of Calcutta, India
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31
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Abaskharon RM, Gai F. Meandering Down the Energy Landscape of Protein Folding: Are We There Yet? Biophys J 2017; 110:1924-32. [PMID: 27166801 DOI: 10.1016/j.bpj.2016.03.030] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 03/18/2016] [Accepted: 03/22/2016] [Indexed: 12/11/2022] Open
Abstract
As judged by a single publication metric, the activity in the protein folding field has been declining over the past 5 years, after enjoying a decade-long growth. Does this development indicate that the field is sunsetting or is this decline only temporary? Upon surveying a small territory of its landscape, we find that the protein folding field is still quite active and many important findings have emerged from recent experimental studies. However, it is also clear that only continued development of new techniques and methods, especially those enabling dissection of the fine details and features of the protein folding energy landscape, will fuel this old field to move forward.
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Affiliation(s)
- Rachel M Abaskharon
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Feng Gai
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania; The Ultrafast Optical Processes Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania.
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32
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Tang T, Jo A, Deng J, Ellena JF, Lazar IM, Davis RM, Capelluto DGS. Structural, thermodynamic, and phosphatidylinositol 3-phosphate binding properties of Phafin2. Protein Sci 2017; 26:814-823. [PMID: 28152563 PMCID: PMC5368057 DOI: 10.1002/pro.3128] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 01/06/2017] [Accepted: 01/11/2017] [Indexed: 02/02/2023]
Abstract
Phafin2 is a phosphatidylinositol 3-phosphate (PtdIns(3)P) binding protein involved in the regulation of endosomal cargo trafficking and lysosomal induction of autophagy. Binding of Phafin2 to PtdIns(3)P is mediated by both its PH and FYVE domains. However, there are no studies on the structural basis, conformational stability, and lipid interactions of Phafin2 to better understand how this protein participates in signaling at the surface of endomembrane compartments. Here, we show that human Phafin2 is a moderately elongated monomer of ∼28 kDa with an intensity-average hydrodynamic diameter of ∼7 nm. Circular dichroism (CD) analysis indicates that Phafin2 exhibits an α/β structure and predicts ∼40% random coil content in the protein. Heteronuclear NMR data indicates that a unique conformation of Phafin2 is present in solution and dispersion of resonances suggests that the protein exhibits random coiled regions, in agreement with the CD data. Phafin2 is stable, displaying a melting temperature of 48.4°C. The folding-unfolding curves, obtained using urea- and guanidine hydrochloride-mediated denaturation, indicate that Phafin2 undergoes a two-state native-to-denatured transition. Analysis of these transitions shows that the free energy change for urea- and guanidine hydrochloride-induced Phafin2 denaturation in water is ∼4 kcal mol-1 . PtdIns(3)P binding to Phafin2 occurs with high affinity, triggering minor conformational changes in the protein. Taken together, these studies represent a platform for establishing the structural basis of Phafin2 molecular interactions and the role of the two potentially redundant PtdIns(3)P-binding domains of the protein in endomembrane compartments.
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Affiliation(s)
- Tuo‐Xian Tang
- Protein Signaling Domains Laboratory, Department of Biological SciencesBiocomplexity Institute, and Center for Soft Matter and Biological Physics, Virginia TechBlacksburgVirginia24061
| | - Ami Jo
- Department of Chemical EngineeringVirginia TechBlacksburgVirginia24061
| | - Jingren Deng
- Department of Biological SciencesVirginia TechBlacksburgVirginia24061
| | - Jeffrey F. Ellena
- Biomolecular Magnetic Resonance Facility, University of VirginiaCharlottesvilleVirginia22904
| | - Iulia M. Lazar
- Department of Biological SciencesVirginia TechBlacksburgVirginia24061
| | - Richey M. Davis
- Department of Chemical EngineeringVirginia TechBlacksburgVirginia24061
| | - Daniel G. S. Capelluto
- Protein Signaling Domains Laboratory, Department of Biological SciencesBiocomplexity Institute, and Center for Soft Matter and Biological Physics, Virginia TechBlacksburgVirginia24061
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33
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Paharik AE, Kotasinska M, Both A, Hoang TMN, Büttner H, Roy P, Fey PD, Horswill AR, Rohde H. The metalloprotease SepA governs processing of accumulation-associated protein and shapes intercellular adhesive surface properties in Staphylococcus epidermidis. Mol Microbiol 2017; 103:860-874. [PMID: 27997732 DOI: 10.1111/mmi.13594] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2016] [Indexed: 12/11/2022]
Abstract
The otherwise harmless skin inhabitant Staphylococcus epidermidis is a major cause of healthcare-associated medical device infections. The species' selective pathogenic potential depends on its production of surface adherent biofilms. The Cell wall-anchored protein Aap promotes biofilm formation in S. epidermidis, independently from the polysaccharide intercellular adhesin PIA. Aap requires proteolytic cleavage to act as an intercellular adhesin. Whether and which staphylococcal proteases account for Aap processing is yet unknown. Here, evidence is provided that in PIA-negative S. epidermidis 1457Δica, the metalloprotease SepA is required for Aap-dependent S. epidermidis biofilm formation in static and dynamic biofilm models. qRT-PCR and protease activity assays demonstrated that under standard growth conditions, sepA is repressed by the global regulator SarA. Inactivation of sarA increased SepA production, and in turn augmented biofilm formation. Genetic and biochemical analyses demonstrated that SepA-related induction of biofilm accumulation resulted from enhanced Aap processing. Studies using recombinant proteins demonstrated that SepA is able to cleave the A domain of Aap at residue 335 and between the A and B domains at residue 601. This study identifies the mechanism behind Aap-mediated biofilm maturation, and also demonstrates a novel role for a secreted staphylococcal protease as a requirement for the development of a biofilm.
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Affiliation(s)
- Alexandra E Paharik
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Marta Kotasinska
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Anna Both
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Tra-My N Hoang
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Henning Büttner
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Paroma Roy
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Paul D Fey
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Alexander R Horswill
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Holger Rohde
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
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34
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Yarawsky AE, English LR, Whitten ST, Herr AB. The Proline/Glycine-Rich Region of the Biofilm Adhesion Protein Aap Forms an Extended Stalk that Resists Compaction. J Mol Biol 2017; 429:261-279. [PMID: 27890783 PMCID: PMC5363081 DOI: 10.1016/j.jmb.2016.11.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Revised: 11/22/2016] [Accepted: 11/22/2016] [Indexed: 12/11/2022]
Abstract
Staphylococcus epidermidis is one of the primary bacterial species responsible for healthcare-associated infections. The most significant virulence factor for S. epidermidis is its ability to form a biofilm, which renders the bacteria highly resistant to host immune responses and antibiotic action. Intercellular adhesion within the biofilm is mediated by the accumulation-associated protein (Aap), a cell wall-anchored protein that self-assembles in a zinc-dependent manner. The C-terminal portion of Aap contains a 135-aa-long, proline/glycine-rich region (PGR) that has not yet been characterized. The region contains a set of 18 nearly identical AEPGKP repeats. Analysis of the PGR using biophysical techniques demonstrated the region is a highly extended, intrinsically disordered polypeptide with unusually high polyproline type II helix propensity. In contrast to many intrinsically disordered polypeptides, there was a minimal temperature dependence of the global conformational state of PGR in solution as measured by analytical ultracentrifugation and dynamic light scattering. Furthermore, PGR was resistant to conformational collapse or α-helix formation upon the addition of the osmolyte trimethylamine N-oxide or the cosolvent 2,2,2-trifluoroethanol. Collectively, these results suggest PGR functions as a resilient, extended stalk that projects the rest of Aap outward from the bacterial cell wall, promoting intercellular adhesion between cells in the biofilm. This work sheds light on regions of low complexity often found near the attachment point of bacterial cell wall-anchored proteins.
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Affiliation(s)
- Alexander E Yarawsky
- Graduate Program in Molecular Genetics, Biochemistry & Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA; Division of Immunobiology and Center for Systems Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Lance R English
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | - Steven T Whitten
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | - Andrew B Herr
- Division of Immunobiology and Center for Systems Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Division of Infectious Diseases, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.
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35
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Functional consequences of B-repeat sequence variation in the staphylococcal biofilm protein Aap: deciphering the assembly code. Biochem J 2016; 474:427-443. [PMID: 27872164 DOI: 10.1042/bcj20160675] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 11/07/2016] [Accepted: 11/21/2016] [Indexed: 01/27/2023]
Abstract
Staphylococcus epidermidis is an opportunistic pathogen that can form robust biofilms that render the bacteria resistant to antibiotic action and immune responses. Intercellular adhesion in S. epidermidis biofilms is mediated by the cell wall-associated accumulation-associated protein (Aap), via zinc-mediated self-assembly of its B-repeat region. This region contains up to 17 nearly identical sequence repeats, with each repeat assumed to be functionally equivalent. However, Aap B-repeats exist as two subtypes, defined by a cluster of consensus or variant amino acids. These variable residues are positioned near the zinc-binding (and dimerization) site and the stability determinant for the B-repeat fold. We have characterized four B-repeat constructs to assess the functional relevance of the two Aap B-repeat subtypes. Analytical ultracentrifugation experiments demonstrated that constructs with the variant sequence show reduced or absent Zn2+-induced dimerization. Likewise, circular dichroism thermal denaturation experiments showed that the variant sequence could significantly stabilize the fold, depending on its location within the construct. Crystal structures of three of the constructs revealed that the side chains from the variant sequence form an extensive bonding network that can stabilize the fold. Furthermore, altered distribution of charged residues between consensus and variant sequences changes the electrostatic potential in the vicinity of the Zn2+-binding site, providing a mechanistic explanation for the loss of zinc-induced dimerization in the variant constructs. These data suggest an assembly code that defines preferred oligomerization modes of the B-repeat region of Aap and a slip-grip model for initial contact followed by firm intercellular adhesion during biofilm formation.
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36
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Gunning AP, Kavanaugh D, Thursby E, Etzold S, MacKenzie DA, Juge N. Use of Atomic Force Microscopy to Study the Multi-Modular Interaction of Bacterial Adhesins to Mucins. Int J Mol Sci 2016; 17:ijms17111854. [PMID: 27834807 PMCID: PMC5133854 DOI: 10.3390/ijms17111854] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 10/26/2016] [Accepted: 11/02/2016] [Indexed: 01/08/2023] Open
Abstract
The mucus layer covering the gastrointestinal (GI) epithelium is critical in selecting and maintaining homeostatic interactions with our gut bacteria. However, the molecular details of these interactions are not well understood. Here, we provide mechanistic insights into the adhesion properties of the canonical mucus-binding protein (MUB), a large multi-repeat cell–surface adhesin found in Lactobacillus inhabiting the GI tract. We used atomic force microscopy to unravel the mechanism driving MUB-mediated adhesion to mucins. Using single-molecule force spectroscopy we showed that MUB displayed remarkable adhesive properties favouring a nanospring-like adhesion model between MUB and mucin mediated by unfolding of the multiple repeats constituting the adhesin. We obtained direct evidence for MUB self-interaction; MUB–MUB followed a similar binding pattern, confirming that MUB modular structure mediated such mechanism. This was in marked contrast with the mucin adhesion behaviour presented by Galectin-3 (Gal-3), a mammalian lectin characterised by a single carbohydrate binding domain (CRD). The binding mechanisms reported here perfectly match the particular structural organization of MUB, which maximizes interactions with the mucin glycan receptors through its long and linear multi-repeat structure, potentiating the retention of bacteria within the outer mucus layer.
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Affiliation(s)
- A Patrick Gunning
- The Gut Health and Food Safety Institute Strategic Programme, Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK.
| | - Devon Kavanaugh
- The Gut Health and Food Safety Institute Strategic Programme, Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK.
| | - Elizabeth Thursby
- The Gut Health and Food Safety Institute Strategic Programme, Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK.
| | - Sabrina Etzold
- The Gut Health and Food Safety Institute Strategic Programme, Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK.
- Division of Neonatology and Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, School of Medicine, University of California San Diego, 9500 Gilman Drive, San Diego, CA 92093-0715, USA.
| | - Donald A MacKenzie
- The Gut Health and Food Safety Institute Strategic Programme, Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK.
| | - Nathalie Juge
- The Gut Health and Food Safety Institute Strategic Programme, Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK.
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37
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Xiao J, Dufrêne YF. Optical and force nanoscopy in microbiology. Nat Microbiol 2016; 1:16186. [PMID: 27782138 PMCID: PMC5839876 DOI: 10.1038/nmicrobiol.2016.186] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 09/01/2016] [Indexed: 12/31/2022]
Abstract
Microbial cells have developed sophisticated multicomponent structures and machineries to govern basic cellular processes, such as chromosome segregation, gene expression, cell division, mechanosensing, cell adhesion and biofilm formation. Because of the small cell sizes, subcellular structures have long been difficult to visualize using diffraction-limited light microscopy. During the last three decades, optical and force nanoscopy techniques have been developed to probe intracellular and extracellular structures with unprecedented resolutions, enabling researchers to study their organization, dynamics and interactions in individual cells, at the single-molecule level, from the inside out, and all the way up to cell-cell interactions in microbial communities. In this Review, we discuss the principles, advantages and limitations of the main optical and force nanoscopy techniques available in microbiology, and we highlight some outstanding questions that these new tools may help to answer.
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Affiliation(s)
- Jie Xiao
- Department of Biophysics &Biophysical Chemistry, The Johns Hopkins School of Medicine, 725 N. Wolfe Street, Baltimore, Maryland 21212, USA
| | - Yves F Dufrêne
- Institute of Life Sciences, Université catholique de Louvain, Croix du Sud, 4-5, bte L7.07.06., B-1348 Louvain-la-Neuve, Belgium
- Walloon Excellence in Life sciences and Biotechnology (WELBIO), Belgium
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38
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Abstract
Many human proteins contain intrinsically disordered regions, and disorder in these proteins can be fundamental to their function-for example, facilitating transient but specific binding, promoting allostery, or allowing efficient posttranslational modification. SasG, a multidomain protein implicated in host colonization and biofilm formation in Staphylococcus aureus, provides another example of how disorder can play an important role. Approximately one-half of the domains in the extracellular repetitive region of SasG are intrinsically unfolded in isolation, but these E domains fold in the context of their neighboring folded G5 domains. We have previously shown that the intrinsic disorder of the E domains mediates long-range cooperativity between nonneighboring G5 domains, allowing SasG to form a long, rod-like, mechanically strong structure. Here, we show that the disorder of the E domains coupled with the remarkable stability of the interdomain interface result in cooperative folding kinetics across long distances. Formation of a small structural nucleus at one end of the molecule results in rapid structure formation over a distance of 10 nm, which is likely to be important for the maintenance of the structural integrity of SasG. Moreover, if this normal folding nucleus is disrupted by mutation, the interdomain interface is sufficiently stable to drive the folding of adjacent E and G5 domains along a parallel folding pathway, thus maintaining cooperative folding.
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39
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Tanner JJ. Empirical power laws for the radii of gyration of protein oligomers. Acta Crystallogr D Struct Biol 2016; 72:1119-1129. [PMID: 27710933 PMCID: PMC5053138 DOI: 10.1107/s2059798316013218] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Accepted: 08/16/2016] [Indexed: 11/10/2022] Open
Abstract
The radius of gyration is a fundamental structural parameter that is particularly useful for describing polymers. It has been known since Flory's seminal work in the mid-20th century that polymers show a power-law dependence, where the radius of gyration is proportional to the number of residues raised to a power. The power-law exponent has been measured experimentally for denatured proteins and derived empirically for folded monomeric proteins using crystal structures. Here, the biological assemblies in the Protein Data Bank are surveyed to derive the power-law parameters for protein oligomers having degrees of oligomerization of 2-6 and 8. The power-law exponents for oligomers span a narrow range of 0.38-0.41, which is close to the value of 0.40 obtained for monomers. This result shows that protein oligomers exhibit essentially the same power-law behavior as monomers. A simple power-law formula is provided for estimating the oligomeric state from an experimental measurement of the radius of gyration. Several proteins in the Protein Data Bank are found to deviate substantially from power-law behavior by having an atypically large radius of gyration. Some of the outliers have highly elongated structures, such as coiled coils. For coiled coils, the radius of gyration does not follow a power law and instead scales linearly with the number of residues in the oligomer. Other outliers are proteins whose oligomeric state or quaternary structure is incorrectly annotated in the Protein Data Bank. The power laws could be used to identify such errors and help prevent them in future depositions.
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Affiliation(s)
- John J. Tanner
- Departments of Biochemistry and Chemistry, University of Missouri-Columbia, Columbia, MO 65211, USA
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Two repetitive, biofilm-forming proteins from Staphylococci: from disorder to extension. Biochem Soc Trans 2016; 43:861-6. [PMID: 26517895 DOI: 10.1042/bst20150088] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Staphylococcus aureus and Staphylococcus epidermidis are an important cause of medical device-related infections that are difficult to treat with antibiotics. Biofilms, in which bacteria are embedded in a bacterially-produced exopolymeric matrix, form on the surface of the implanted medical device. Our understanding of the molecular mechanisms underlying the initial surface attachment and subsequent intercellular interactions as the biofilm matures is improving. Biofilm accumulation can be mediated by a partially deacetylated form of poly-N-acetylglucosamine (PNAG) but, more recently, the role of bacterial surface proteins is being recognized. Here we describe the structure and function of two S. aureus cell surface proteins, FnBPA and SasG, implicated in host interactions and biofilm accumulation. These multifunctional proteins employ intrinsic disorder for distinct molecular outcomes. In the case of FnBPA, disorder generates adhesive arrays that bind fibronectin (Fn); in the case of SasG, disorder is, counterintuitively, used to maintain a strong extended fold.
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Application of advanced X-ray methods in life sciences. Biochim Biophys Acta Gen Subj 2016; 1861:3671-3685. [PMID: 27156488 DOI: 10.1016/j.bbagen.2016.05.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 05/03/2016] [Accepted: 05/04/2016] [Indexed: 12/19/2022]
Abstract
BACKGROUND Synchrotron radiation (SR) sources provide diverse X-ray methods for the investigation of structure-function relationships in biological macromolecules. SCOPE OF REVIEW Recent developments in SR sources and in the X-ray tools they offer for life sciences are reviewed. Specifically, advances in macromolecular crystallography, small angle X-ray solution scattering, X-ray absorption and fluorescence spectroscopy, and imaging are discussed with examples. MAJOR CONCLUSIONS SR sources offer a range of X-ray techniques that can be used in a complementary fashion in studies of biological systems at a wide range of resolutions from atomic to cellular scale. Emerging applications of X-ray techniques include the characterization of disordered proteins, noncrystalline and nonequilibrium systems, elemental imaging of tissues, cells and organs, and detection of time-resolved changes in molecular structures. GENERAL SIGNIFICANCE X-ray techniques are in the center of hybrid approaches that are used to gain insight into complex problems relating to biomolecular mechanisms, disease and possible therapeutic solutions. This article is part of a Special Issue entitled "Science for Life". Guest Editors: Dr. Austen Angell, Dr. Salvatore Magazù and Dr. Federica Migliardo.
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Affiliation(s)
- A. Subha Mahadevi
- Centre for Molecular Modelling, CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India 500607
| | - G. Narahari Sastry
- Centre for Molecular Modelling, CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India 500607
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Zinc-dependent mechanical properties of Staphylococcus aureus biofilm-forming surface protein SasG. Proc Natl Acad Sci U S A 2015; 113:410-5. [PMID: 26715750 DOI: 10.1073/pnas.1519265113] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Staphylococcus aureus surface protein SasG promotes cell-cell adhesion during the accumulation phase of biofilm formation, but the molecular basis of this interaction remains poorly understood. Here, we unravel the mechanical properties of SasG on the surface of living bacteria, that is, in its native cellular environment. Nanoscale multiparametric imaging of living bacteria reveals that Zn(2+) strongly increases cell wall rigidity and activates the adhesive function of SasG. Single-cell force measurements show that SasG mediates cell-cell adhesion via specific Zn(2+)-dependent homophilic bonds between β-sheet-rich G5-E domains on neighboring cells. The force required to unfold individual domains is remarkably strong, up to ∼500 pN, thus explaining how SasG can withstand physiological shear forces. We also observe that SasG forms homophilic bonds with the structurally related accumulation-associated protein of Staphylococcus epidermidis, suggesting the possibility of multispecies biofilms during host colonization and infection. Collectively, our findings support a model in which zinc plays a dual role in activating cell-cell adhesion: adsorption of zinc ions to the bacterial cell surface increases cell wall cohesion and favors the projection of elongated SasG proteins away from the cell surface, thereby enabling zinc-dependent homophilic bonds between opposing cells. This work demonstrates an unexpected relationship between mechanics and adhesion in a staphylococcal surface protein, which may represent a general mechanism among bacterial pathogens for activating cell association.
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Herman-Bausier P, Formosa-Dague C, Feuillie C, Valotteau C, Dufrêne YF. Forces guiding staphylococcal adhesion. J Struct Biol 2015; 197:65-69. [PMID: 26707623 DOI: 10.1016/j.jsb.2015.12.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 12/15/2015] [Accepted: 12/17/2015] [Indexed: 10/22/2022]
Abstract
Staphylococcus epidermidis and Staphylococcus aureus are two important nosocomial pathogens that form biofilms on indwelling medical devices. Biofilm infections are difficult to fight as cells within the biofilm show increased resistance to antibiotics. Our understanding of the molecular interactions driving bacterial adhesion, the first stage of biofilm formation, has long been hampered by the paucity of appropriate force-measuring techniques. In this minireview, we discuss how atomic force microscopy techniques have enabled to shed light on the molecular forces at play during staphylococcal adhesion. Specific highlights include the study of the binding mechanisms of adhesion molecules by means of single-molecule force spectroscopy, the measurement of the forces involved in whole cell interactions using single-cell force spectroscopy, and the probing of the nanobiophysical properties of living bacteria via multiparametric imaging. Collectively, these findings emphasize the notion that force and function are tightly connected in staphylococcal adhesion.
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Affiliation(s)
- Philippe Herman-Bausier
- Université catholique de Louvain, Institute of Life Sciences, Croix du Sud 4-5, bte L7.07.06, B-1348 Louvain-la-Neuve, Belgium
| | - Cécile Formosa-Dague
- Université catholique de Louvain, Institute of Life Sciences, Croix du Sud 4-5, bte L7.07.06, B-1348 Louvain-la-Neuve, Belgium
| | - Cécile Feuillie
- Université catholique de Louvain, Institute of Life Sciences, Croix du Sud 4-5, bte L7.07.06, B-1348 Louvain-la-Neuve, Belgium
| | - Claire Valotteau
- Université catholique de Louvain, Institute of Life Sciences, Croix du Sud 4-5, bte L7.07.06, B-1348 Louvain-la-Neuve, Belgium
| | - Yves F Dufrêne
- Université catholique de Louvain, Institute of Life Sciences, Croix du Sud 4-5, bte L7.07.06, B-1348 Louvain-la-Neuve, Belgium; Walloon Excellence in Life Sciences and Biotechnology (WELBIO), Belgium.
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Cell Wall-Anchored Surface Proteins of Staphylococcus aureus: Many Proteins, Multiple Functions. Curr Top Microbiol Immunol 2015; 409:95-120. [PMID: 26667044 DOI: 10.1007/82_2015_5002] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Staphylococcus aureus persistently colonizes about 20 % of the population and is intermittently associated with the remainder. The organism can cause superficial skin infections and life-threatening invasive diseases. The surface of the bacterial cell displays a variety of proteins that are covalently anchored to peptidoglycan. They perform many functions including adhesion to host cells and tissues, invasion of non-phagocytic cells, and evasion of innate immune responses. The proteins have been categorized into distinct classes based on structural and functional analysis. Many surface proteins are multifunctional. Cell wall-anchored proteins perform essential functions supporting survival and proliferation during the commensal state and during invasive infections. The ability of cell wall-anchored proteins to bind to desquamated epithelial cells is important during colonization, and the binding to fibrinogen is of particular significance in pathogenesis.
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