101
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The Molecular Complex between Staphylococcal Adhesin SpsD and Fibronectin Sustains Mechanical Forces in the Nanonewton Range. mBio 2020; 11:mBio.00371-20. [PMID: 32636242 PMCID: PMC7343985 DOI: 10.1128/mbio.00371-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The bacterial pathogen Staphylococcus pseudintermedius is involved in canine otitis externa and pyoderma as well as in surgical wound and urinary tract infections. Invasion of canine epithelial cells is promoted by S. pseudintermedius fibronectin (Fn)-binding proteins SpsD and SpsL through molecular interactions that are currently unknown. By means of single-molecule experiments, we discover that both adhesins have distinct molecular mechanisms for binding to Fn. We show that the SpsD-Fn interaction has a strength equivalent to that of a covalent bond (∼1.5 to 1.8 nN), which is an order of magnitude stronger than the binding force of classical receptor-ligand complexes. We suggest that this extreme mechanostability originates from the β-sheet organization of a tandem β-zipper. Upon binding to FnI modules, the intrinsically disordered binding sequences of SpsD would shift into an ordered structure by forming additional β-strands along triple peptide β-sheets in the Fn molecule. Dynamic force measurements reveal an unexpected behavior, i.e., that strong bonds are activated by mechanical tension as observed with catch bonds. By contrast, the SpsL-Fn interaction involves multiple weak bonds (∼0.2 nN) that rupture sequentially under force. Together with the recently described dock, lock, and latch complex, the ultrastrong interaction unraveled here is among the strongest noncovalent biological interaction measured to date. Our findings may find applications for the identification of inhibitory compounds to treat infections triggered by pathogens engaged in tandem β-zipper interactions.IMPORTANCE Binding of Staphylococcus pseudintermedius surface proteins SpsD and SpsL to fibronectin (Fn) plays a critical role in the invasion of canine epithelial cells. Here, we discover that both adhesins have different mechanisms for binding to Fn. The force required to separate SpsD from Fn is extremely strong, consistent with the unusual β-sheet organization of a high-affinity tandem β-zipper. By contrast, unbinding of the SpsL-Fn complex involves the sequential rupture of single weak bonds. Our findings may be of biological relevance as SpsD and SpsL are likely to play complementary roles during invasion. While the SpsD β-zipper supports strong bacterial adhesion and triggers invasion, the weak SpsL interaction would favor fast detachment, enabling the pathogen to colonize new sites.
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102
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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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103
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El-Kirat-Chatel S, Beaussart A, Mathelié-Guinlet M, Dufrêne YF. The importance of force in microbial cell adhesion. Curr Opin Colloid Interface Sci 2020. [DOI: 10.1016/j.cocis.2019.12.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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104
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Abstract
Microbial adhesion and biofilm formation are usually studied using molecular and cellular biology assays, optical and electron microscopy, or laminar flow chamber experiments. Today, atomic force microscopy (AFM) represents a valuable addition to these approaches, enabling the measurement of forces involved in microbial adhesion at the single-molecule level. In this minireview, we discuss recent discoveries made applying state-of-the-art AFM techniques to microbial specimens in order to understand the strength and dynamics of adhesive interactions. These studies shed new light on the molecular mechanisms of adhesion and demonstrate an intimate relationship between force and function in microbial adhesins.
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105
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Yang B, Liu Z, Liu H, Nash MA. Next Generation Methods for Single-Molecule Force Spectroscopy on Polyproteins and Receptor-Ligand Complexes. Front Mol Biosci 2020; 7:85. [PMID: 32509800 PMCID: PMC7248566 DOI: 10.3389/fmolb.2020.00085] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 04/16/2020] [Indexed: 12/31/2022] Open
Abstract
Single-molecule force spectroscopy with the atomic force microscope provides molecular level insights into protein function, allowing researchers to reconstruct energy landscapes and understand functional mechanisms in biology. With steadily advancing methods, this technique has greatly accelerated our understanding of force transduction, mechanical deformation, and mechanostability within single- and multi-domain polyproteins, and receptor-ligand complexes. In this focused review, we summarize the state of the art in terms of methodology and highlight recent methodological improvements for AFM-SMFS experiments, including developments in surface chemistry, considerations for protein engineering, as well as theory and algorithms for data analysis. We hope that by condensing and disseminating these methods, they can assist the community in improving data yield, reliability, and throughput and thereby enhance the information that researchers can extract from such experiments. These leading edge methods for AFM-SMFS will serve as a groundwork for researchers cognizant of its current limitations who seek to improve the technique in the future for in-depth studies of molecular biomechanics.
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Affiliation(s)
- Byeongseon Yang
- Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Zhaowei Liu
- Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Haipei Liu
- Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Michael A. Nash
- Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
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106
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Schendel LC, Bauer MS, Sedlak SM, Gaub HE. Single-Molecule Manipulation in Zero-Mode Waveguides. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e1906740. [PMID: 32141169 DOI: 10.1002/smll.201906740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 02/08/2020] [Indexed: 06/10/2023]
Abstract
The mechanobiology of receptor-ligand interactions and force-induced enzymatic turnover can be revealed by simultaneous measurements of force response and fluorescence. Investigations at physiologically relevant high labeled substrate concentrations require total internal reflection fluorescence microscopy or zero mode waveguides (ZMWs), which are difficult to combine with atomic force microscopy (AFM). A fully automatized workflow is established to manipulate single molecules inside ZMWs autonomously with noninvasive cantilever tip localization. A protein model system comprising a receptor-ligand pair of streptavidin blocked with a biotin-tagged ligand is introduced. The ligand is pulled out of streptavidin by an AFM cantilever leaving the receptor vacant for reoccupation by freely diffusing fluorescently labeled biotin, which can be detected in single-molecule fluorescence concurrently to study rebinding rates. This work illustrates the potential of the seamless fusion of these two powerful single-molecule techniques.
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Affiliation(s)
- Leonard C Schendel
- Lehrstuhl für Angewandte Physik and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Amalienstrasse 54, Munich, 80799, Germany
| | - Magnus S Bauer
- Lehrstuhl für Angewandte Physik and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Amalienstrasse 54, Munich, 80799, Germany
| | - Steffen M Sedlak
- Lehrstuhl für Angewandte Physik and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Amalienstrasse 54, Munich, 80799, Germany
| | - Hermann E Gaub
- Lehrstuhl für Angewandte Physik and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Amalienstrasse 54, Munich, 80799, Germany
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107
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Abstract
The complex of the small molecule biotin and the homotetrameric protein streptavidin is key to a broad range of biotechnological applications. Therefore, the behavior of this extraordinarily high-affinity interaction under mechanical force is intensively studied by single-molecule force spectroscopy. Recently, steered molecular dynamics simulations have identified a low force pathway for the dissociation of biotin from streptavidin, which involves partial unfolding of the N-terminal β-sheet structure of monovalent streptavidin's functional subunit. Based on these results, we now introduced two mutations (T18C,A33C) in the functional subunit of monovalent streptavidin to establish a switchable connection (disulfide bridge) between the first two β-strands to prevent this unfolding. In atomic force microscopy-based single-molecule force spectroscopy experiments, we observed unbinding forces of about 350 pN (at a force-loading rate of 10 nN s-1) for pulling a single biotin out of an N-terminally anchored monovalent streptavidin binding pocket - about 1.5-fold higher compared with what has been reported for N-terminal force loading of native monovalent streptavidin. Upon addition of a reducing agent, the unbinding forces dropped back to 200 pN, as the disulfide bridge was destroyed. Switching from reducing to oxidizing buffer conditions, the inverse effect was observed. Our work illustrates how the mechanics of a receptor-ligand system can be tuned by engineering the receptor protein far off the ligand-binding pocket.
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Affiliation(s)
- Leonard C Schendel
- Lehrstuhl für Angewandte Physik and Center for NanoScience, Ludwig-Maximilians-Universität München, Amalienstr. 54, 80799 Munich, Germany.
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108
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Sedlak SM, Schendel LC, Gaub HE, Bernardi RC. Streptavidin/biotin: Tethering geometry defines unbinding mechanics. SCIENCE ADVANCES 2020; 6:eaay5999. [PMID: 32232150 PMCID: PMC7096159 DOI: 10.1126/sciadv.aay5999] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 01/03/2020] [Indexed: 05/26/2023]
Abstract
Macromolecules tend to respond to applied forces in many different ways. Chemistry at high shear forces can be intriguing, with relatively soft bonds becoming very stiff in specific force-loading geometries. Largely used in bionanotechnology, an important case is the streptavidin (SA)/biotin interaction. Although SA's four subunits have the same affinity, we find that the forces required to break the SA/biotin bond depend strongly on the attachment geometry. With AFM-based single-molecule force spectroscopy (SMFS), we measured unbinding forces of biotin from different SA subunits to range from 100 to more than 400 pN. Using a wide-sampling approach, we carried out hundreds of all-atom steered molecular dynamics (SMD) simulations for the entire system, including molecular linkers. Our strategy revealed the molecular mechanism that causes a fourfold difference in mechanical stability: Certain force-loading geometries induce conformational changes in SA's binding pocket lowering the energy barrier, which biotin has to overcome to escape the pocket.
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Affiliation(s)
- Steffen M. Sedlak
- Lehrstuhl für Angewandte Physik and Center for NanoScience, Ludwig-Maximilians-Universität München, Amalienstr. 54, 80799 Munich, Germany
| | - Leonard C. Schendel
- Lehrstuhl für Angewandte Physik and Center for NanoScience, Ludwig-Maximilians-Universität München, Amalienstr. 54, 80799 Munich, Germany
| | - Hermann E. Gaub
- Lehrstuhl für Angewandte Physik and Center for NanoScience, Ludwig-Maximilians-Universität München, Amalienstr. 54, 80799 Munich, Germany
| | - Rafael C. Bernardi
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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109
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Dahal N, Nowitzke J, Eis A, Popa I. Binding-Induced Stabilization Measured on the Same Molecular Protein Substrate Using Single-Molecule Magnetic Tweezers and Heterocovalent Attachments. J Phys Chem B 2020; 124:3283-3290. [DOI: 10.1021/acs.jpcb.0c00167] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Narayan Dahal
- Department of Physics, University of Wisconsin-Milwaukee, 3135 North Maryland Avenue, Milwaukee, Wisconsin 53211, United States
| | - Joel Nowitzke
- Department of Physics, University of Wisconsin-Milwaukee, 3135 North Maryland Avenue, Milwaukee, Wisconsin 53211, United States
| | - Annie Eis
- Department of Physics, University of Wisconsin-Milwaukee, 3135 North Maryland Avenue, Milwaukee, Wisconsin 53211, United States
| | - Ionel Popa
- Department of Physics, University of Wisconsin-Milwaukee, 3135 North Maryland Avenue, Milwaukee, Wisconsin 53211, United States
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110
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Extreme mechanical stability in protein complexes. Curr Opin Struct Biol 2020; 60:124-130. [DOI: 10.1016/j.sbi.2019.11.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/14/2019] [Accepted: 11/27/2019] [Indexed: 12/21/2022]
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111
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Mechanomicrobiology: how bacteria sense and respond to forces. Nat Rev Microbiol 2020; 18:227-240. [DOI: 10.1038/s41579-019-0314-2] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/06/2019] [Indexed: 12/26/2022]
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112
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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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113
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Mora M, Stannard A, Garcia-Manyes S. The nanomechanics of individual proteins. Chem Soc Rev 2020; 49:6816-6832. [DOI: 10.1039/d0cs00426j] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This tutorial review provides an overview of the single protein force spectroscopy field, including the main techniques and the basic tools for analysing the data obtained from the single molecule experiments.
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Affiliation(s)
- Marc Mora
- Department of Physics and Randall Centre for Cell and Molecular Biophysics
- King's College London
- London
- UK
- The Francis Crick Institute
| | - Andrew Stannard
- Department of Physics and Randall Centre for Cell and Molecular Biophysics
- King's College London
- London
- UK
- The Francis Crick Institute
| | - Sergi Garcia-Manyes
- Department of Physics and Randall Centre for Cell and Molecular Biophysics
- King's College London
- London
- UK
- The Francis Crick Institute
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114
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Mathelié-Guinlet M, Viela F, Viljoen A, Dehullu J, Dufrêne YF. Single-molecule atomic force microscopy studies of microbial pathogens. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2019. [DOI: 10.1016/j.cobme.2019.08.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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115
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Le S, Yu M, Yan J. Direct single-molecule quantification reveals unexpectedly high mechanical stability of vinculin-talin/α-catenin linkages. SCIENCE ADVANCES 2019; 5:eaav2720. [PMID: 31897422 PMCID: PMC6920023 DOI: 10.1126/sciadv.aav2720] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 10/29/2019] [Indexed: 05/26/2023]
Abstract
The vinculin-mediated mechanosensing requires establishment of stable mechanical linkages between vinculin to integrin at focal adhesions and to cadherins at adherens junctions through associations with the respective adaptor proteins talin and α-catenin. However, the mechanical stability of these critical vinculin linkages has yet to be determined. Here, we developed a single-molecule detector assay to provide direct quantification of the mechanical lifetime of vinculin association with the vinculin binding sites in both talin and α-catenin, which reveals a surprisingly high mechanical stability of the vinculin-talin and vinculin-α-catenin interfaces that have a lifetime of >1000 s at forces up to 10 pN and can last for seconds to tens of seconds at 15 to 25 pN. Our results suggest that these force-bearing intermolecular interfaces provide sufficient mechanical stability to support the vinculin-mediated mechanotransduction at cell-matrix and cell-cell adhesions.
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Affiliation(s)
- Shimin Le
- Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | - Miao Yu
- Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | - Jie Yan
- Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
- Centre for Bioimaging Sciences, National University of Singapore, Singapore 117546, Singapore
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116
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Viela F, Speziale P, Pietrocola G, Dufrêne YF. Mechanostability of the Fibrinogen Bridge between Staphylococcal Surface Protein ClfA and Endothelial Cell Integrin α Vβ 3. NANO LETTERS 2019; 19:7400-7410. [PMID: 31532212 DOI: 10.1021/acs.nanolett.9b03080] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Binding of the Staphylococcus aureus surface protein clumping factor A (ClfA) to endothelial cell integrin αVβ3 plays a crucial role during sepsis, by causing endothelial cell apoptosis and loss of barrier integrity. ClfA uses the blood plasma protein fibrinogen (Fg) to bind to αVβ3 but how this is achieved at the molecular level is not known. Here we investigate the mechanical strength of the three-component ClfA-Fg-αVβ3 interaction on living bacteria, by means of single-molecule experiments. We find that the ClfA-Fg-αVβ3 ternary complex is extremely stable, being able to sustain forces (∼800 pN) that are much stronger than those of classical bonds between integrins and the Arg-Gly-Asp (RGD) tripeptide sequence (∼100 pN). Adhesion forces between single bacteria and αVβ3 are strongly inhibited by an anti-αVβ3 antibody, the RGD peptide, and the cyclic RGD peptide cilengitide, showing that formation of the complex involves RGD-dependent binding sites and can be efficiently inhibited by αVβ3 blockers. Collectively, our experiments favor a binding mechanism involving the extraordinary elasticity of Fg. In the absence of mechanical stress, RGD572-574 sequences in the Aα chains mediate weak binding to αVβ3, whereas under high mechanical stress exposure of cryptic Aα chain RGD95-97 sequences leads to extremely strong binding to the integrin. Our results identify an unexpected and previously undescribed force-dependent binding mechanism between ClfA and αVβ3 on endothelial cells, which could represent a potential target to fight staphylococcal bloodstream infections.
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Affiliation(s)
- Felipe Viela
- Louvain Institute of Biomolecular Science and Technology, UCLouvain , Croix du Sud, 4-5, bte L7.07.06, B-1348 Louvain-la-Neuve , Belgium
| | - Pietro Speziale
- Department of Molecular Medicine, Unit of Biochemistry , University of Pavia , Viale Taramelli 3/b , 27100 Pavia , Italy
- Department of Industrial and Information Engineering , University of Pavia , 27100 Pavia , Italy
| | - Giampiero Pietrocola
- 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 L7.07.06, B-1348 Louvain-la-Neuve , Belgium
- Walloon Excellence in Life sciences and Biotechnology (WELBIO) , 1300 Wavre , Belgium
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117
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High-speed force spectroscopy: microsecond force measurements using ultrashort cantilevers. Biophys Rev 2019; 11:689-699. [PMID: 31588961 PMCID: PMC6815269 DOI: 10.1007/s12551-019-00585-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 08/27/2019] [Indexed: 10/25/2022] Open
Abstract
Complete understanding of the role of mechanical forces in biological processes requires knowledge of the mechanical properties of individual proteins and living cells. Moreover, the dynamic response of biological systems at the nano- and microscales span over several orders of magnitude in time, from sub-microseconds to several minutes. Thus, access to force measurements over a wide range of length and time scales is required. High-speed atomic force microscopy (HS-AFM) using ultrashort cantilevers has emerged as a tool to study the dynamics of biomolecules and cells at video rates. The adaptation of HS-AFM to perform high-speed force spectroscopy (HS-FS) allows probing protein unfolding and receptor/ligand unbinding up to the velocity of molecular dynamics (MD) simulations with sub-microsecond time resolution. Moreover, application of HS-FS on living cells allows probing the viscoelastic response at short time scales providing deep understanding of cytoskeleton dynamics. In this mini-review, we assess the principles and recent developments and applications of HS-FS using ultrashort cantilevers to probe molecular and cellular mechanics.
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118
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Bernardi RC, Durner E, Schoeler C, Malinowska KH, Carvalho BG, Bayer EA, Luthey-Schulten Z, Gaub HE, Nash MA. Mechanisms of Nanonewton Mechanostability in a Protein Complex Revealed by Molecular Dynamics Simulations and Single-Molecule Force Spectroscopy. J Am Chem Soc 2019; 141:14752-14763. [PMID: 31464132 PMCID: PMC6939381 DOI: 10.1021/jacs.9b06776] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
![]()
Can molecular dynamics
simulations predict the mechanical behavior of protein complexes?
Can simulations decipher the role of protein domains of unknown function
in large macromolecular complexes? Here, we employ a wide-sampling
computational approach to demonstrate that molecular dynamics simulations,
when carefully performed and combined with single-molecule atomic
force spectroscopy experiments, can predict and explain the behavior
of highly mechanostable protein complexes. As a test case, we studied
a previously unreported homologue from Ruminococcus flavefaciens called X-module-Dockerin (XDoc) bound to its partner Cohesin (Coh).
By performing dozens of short simulation replicas near the rupture
event, and analyzing dynamic network fluctuations, we were able to
generate large simulation statistics and directly compare them with
experiments to uncover the mechanisms involved in mechanical stabilization.
Our single-molecule force spectroscopy experiments show that the XDoc-Coh
homologue complex withstands forces up to 1 nN at loading rates of
105 pN/s. Our simulation results reveal that this remarkable
mechanical stability is achieved by a protein architecture that directs
molecular deformation along paths that run perpendicular to the pulling
axis. The X-module was found to play a crucial role in shielding the
adjacent protein complex from mechanical rupture. These mechanisms
of protein mechanical stabilization have potential applications in
biotechnology for the development of systems exhibiting shear enhanced
adhesion or tunable mechanics.
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Affiliation(s)
- Rafael C Bernardi
- Beckman Institute for Advanced Science and Technology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Ellis Durner
- Lehrstuhl für Angewandte Physik and Center for Nanoscience , Ludwig-Maximilians-Universität , 80799 Munich , Germany
| | - Constantin Schoeler
- Lehrstuhl für Angewandte Physik and Center for Nanoscience , Ludwig-Maximilians-Universität , 80799 Munich , Germany
| | - Klara H Malinowska
- Lehrstuhl für Angewandte Physik and Center for Nanoscience , Ludwig-Maximilians-Universität , 80799 Munich , Germany
| | - Bruna G Carvalho
- School of Chemical Engineering , University of Campinas , 13083-852 Campinas , Brazil
| | - Edward A Bayer
- Department of Biomolecular Sciences , Weizmann Institute of Science , 76100 Rehovot , Israel
| | - Zaida Luthey-Schulten
- Beckman Institute for Advanced Science and Technology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States.,Department of Chemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Hermann E Gaub
- Lehrstuhl für Angewandte Physik and Center for Nanoscience , Ludwig-Maximilians-Universität , 80799 Munich , Germany
| | - Michael A Nash
- Department of Chemistry , University of Basel , 4058 Basel , Switzerland.,Department of Biosystems Science and Engineering , ETH Zurich , 4058 Basel , Switzerland
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119
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Multiplexed protein force spectroscopy reveals equilibrium protein folding dynamics and the low-force response of von Willebrand factor. Proc Natl Acad Sci U S A 2019; 116:18798-18807. [PMID: 31462494 PMCID: PMC6754583 DOI: 10.1073/pnas.1901794116] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Single-molecule force spectroscopy has provided unprecedented insights into protein folding, force regulation, and function. So far, the field has relied primarily on atomic force microscope and optical tweezers assays that, while powerful, are limited in force resolution, throughput, and require feedback for constant force measurements. Here, we present a modular approach based on magnetic tweezers (MT) for highly multiplexed protein force spectroscopy. Our approach uses elastin-like polypeptide linkers for the specific attachment of proteins, requiring only short peptide tags on the protein of interest. The assay extends protein force spectroscopy into the low force (<1 pN) regime and enables parallel and ultra-stable measurements at constant forces. We present unfolding and refolding data for the small, single-domain protein ddFLN4, commonly used as a molecular fingerprint in force spectroscopy, and for the large, multidomain dimeric protein von Willebrand factor (VWF) that is critically involved in primary hemostasis. For both proteins, our measurements reveal exponential force dependencies of unfolding and refolding rates. We directly resolve the stabilization of the VWF A2 domain by Ca2+ and discover transitions in the VWF C domain stem at low forces that likely constitute the first steps of VWF's mechano-activation. Probing the force-dependent lifetime of biotin-streptavidin bonds, we find that monovalent streptavidin constructs with specific attachment geometry are significantly more force stable than commercial, multivalent streptavidin. We expect our modular approach to enable multiplexed force-spectroscopy measurements for a wide range of proteins, in particular in the physiologically relevant low-force regime.
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120
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Liu H, Schittny V, Nash MA. Removal of a Conserved Disulfide Bond Does Not Compromise Mechanical Stability of a VHH Antibody Complex. NANO LETTERS 2019; 19:5524-5529. [PMID: 31257893 PMCID: PMC6975629 DOI: 10.1021/acs.nanolett.9b02062] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 06/28/2019] [Indexed: 05/28/2023]
Abstract
Single-domain VHH antibodies are promising reagents for medical therapy. A conserved disulfide bond within the VHH framework region is known to be critical for thermal stability, however, no prior studies have investigated its influence on the stability of VHH antibody-antigen complexes under mechanical load. Here, we used single-molecule force spectroscopy to test the influence of a VHH domain's conserved disulfide bond on the mechanical strength of the interaction with its antigen mCherry. We found that although removal of the disulfide bond through cysteine-to-alanine mutagenesis significantly lowered VHH domain denaturation temperature, it had no significant impact on the mechanical strength of the VHH:mCherry interaction with complex rupture occurring at ∼60 pN at 103-104 pN/sec regardless of disulfide bond state. These results demonstrate that mechanostable binding interactions can be built on molecular scaffolds that may be thermodynamically compromised at equilibrium.
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Affiliation(s)
- Haipei Liu
- Department
of Chemistry, University of Basel, 4058 Basel, Switzerland
- Department
of Biosystems Science and Engineering, ETH
Zurich, 4058 Basel, Switzerland
| | - Valentin Schittny
- Department
of Chemistry, University of Basel, 4058 Basel, Switzerland
- Department
of Biosystems Science and Engineering, ETH
Zurich, 4058 Basel, Switzerland
| | - Michael A. Nash
- Department
of Chemistry, University of Basel, 4058 Basel, Switzerland
- Department
of Biosystems Science and Engineering, ETH
Zurich, 4058 Basel, Switzerland
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Lo Giudice C, Dumitru AC, Alsteens D. Probing ligand-receptor bonds in physiologically relevant conditions using AFM. Anal Bioanal Chem 2019; 411:6549-6559. [PMID: 31410537 DOI: 10.1007/s00216-019-02077-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 07/30/2019] [Accepted: 08/07/2019] [Indexed: 12/16/2022]
Abstract
Cell surface receptors, often called transmembrane receptors, are key cellular components as they control and mediate cell communication and signalling, converting extracellular signals into intracellular signals. Elucidating the molecular details of ligand binding (cytokine, growth factors, hormones, pathogens,...) to cell surface receptors and how this binding triggers conformational changes that initiate intracellular signalling is needed to improve our understanding of cellular processes and for rational drug design. Unfortunately, the molecular complexity and high hydrophobicity of membrane proteins significantly hamper their structural and functional characterization in conditions mimicking their native environment. With its piconewton force sensitivity and (sub)nanometer spatial resolution, together with the capability of operating in liquid environment and at physiological temperature, atomic force microscopy (AFM) has proven to be one of the most powerful tools to image and quantify receptor-ligand bonds in situ under physiologically relevant conditions. In this article, a brief overview of the rapid evolution of AFM towards quantitative biological mapping will be given, followed by selected examples highlighting the main advances that AFM-based ligand-receptor studies have brought to the fields of cell biology, immunology, microbiology, and virology, along with future prospects and challenges. Graphical abstract.
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Affiliation(s)
- Cristina Lo Giudice
- Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Croix du sud 4-5, 1348, Louvain-la-Neuve, Belgium
| | - Andra C Dumitru
- Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Croix du sud 4-5, 1348, Louvain-la-Neuve, Belgium
| | - David Alsteens
- Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Croix du sud 4-5, 1348, Louvain-la-Neuve, Belgium.
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122
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Fibrinogen binding is affected by amino acid substitutions in C-terminal repeat region of fibronectin binding protein A. Sci Rep 2019; 9:11619. [PMID: 31406152 PMCID: PMC6690874 DOI: 10.1038/s41598-019-48031-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 07/29/2019] [Indexed: 11/14/2022] Open
Abstract
Fibronectin-binding protein A (FnBPA), a protein displayed on the outer surface of Staphylococcus aureus, has a structured A-domain that binds fibrinogen (Fg) and a disordered repeat-region that binds fibronectin (Fn). Amino acid substitutions in Fn-binding repeats (FnBRs) have previously been linked to cardiovascular infection in humans. Here we used microtiter and atomic force microscopy (AFM) to investigate adhesion by variants of full-length FnBPA covalently anchored in the outer cell wall of Lactococcus lactis, a Gram-positive surrogate that otherwise lacks adhesins to mammalian ligands. Fn adhesion increased in five of seven FnBPA variants under static conditions. The bond targeting Fn increased its strength with load under mechanical dissociation. Substitutions extended bond lifetime (1/koff) up to 2.1 times for FnBPA-Fn. Weaker adhesion was observed for Fg in all FnBPA variants tested with microtiter. However, mechanical dissociation with AFM showed significantly increased tensile strength for Fg interacting with the E652D/H782Q variant. This is consistent with a force-induced mechanism and suggests that the dock, lock, and latch (DLL) mechanism is favored for Fg-binding under mechanical stress. Collectively, these experiments reveal that FnBPA exhibits bimodal, ligand-dependent adhesive behavior. Amino acid substitutions in the repeat-region of FnBPA impact binding to both ligands. This was unexpected for Fg since all variants have the same A-domain sequence, and the Fg-binding site is distant from the repeat region. This indicates that FnBRs may fold back on the A-domain in a way that impacts the DLL binding mechanism for Fg.
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The MSCRAMM Family of Cell-Wall-Anchored Surface Proteins of Gram-Positive Cocci. Trends Microbiol 2019; 27:927-941. [PMID: 31375310 DOI: 10.1016/j.tim.2019.06.007] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 06/10/2019] [Accepted: 06/19/2019] [Indexed: 01/21/2023]
Abstract
The microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) are a family of proteins that are defined by the presence of two adjacent IgG-like folded subdomains. These promote binding to ligands by mechanisms that involve major conformational changes exemplified by the binding to fibrinogen by the 'dock-lock-latch' mechanism or to collagen by the 'collagen hug'. Clumping factors A and B are two such MSCRAMMs that have several important roles in the pathogenesis of Staphylococcus aureus infections. MSCRAMM architecture, ligand binding, and roles in infection and colonization are examined with a focus on recent developments with clumping factors.
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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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Becke TD, Ness S, Kaufmann BK, Hartmann B, Schilling AF, Sudhop S, Hilleringmann M, Clausen-Schaumann H. Pilus-1 Backbone Protein RrgB of Streptococcus pneumoniae Binds Collagen I in a Force-Dependent Way. ACS NANO 2019; 13:7155-7165. [PMID: 31184856 DOI: 10.1021/acsnano.9b02587] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Attachment to host tissue is a prerequisite for successful host colonization and invasion of pathogens. Many pathogenic bacteria use surface appendices, called pili, to bind and firmly attach to host tissue surfaces. Although it has been speculated that the laterally positioned D3 domain of the pilus-1 backbone protein RrgB of Streptococcus pneumoniae may promote bacterial-host interaction, via adhesion to extracellular matrix molecules, such as collagen, earlier studies showed no affinity of RrgB to collagen I. Using atomic force microscopy-based single molecule force spectroscopy combined with lateral force microscopy, we show that under mechanical load, RrgB in fact binds to human collagen I in a force-dependent manner. We observe exceptionally strong interactions, with interaction forces reaching as much as 1500 pN, and we show that high force loading and shearing rates enhance and further strengthen the interaction. In addition, the affinity of RrgB to collagen I under mechanical load not only depends on the orientation of the D3 domain but also on the orientation of the collagen fibrils, relative to the pulling direction. Both exceptionally high binding forces and force-induced bond strengthening resemble the behavior of so-called catch bonds, which have recently been observed in bacterial adhesins, but have not been reported for multimeric backbone subunits of virulence related pili.
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Affiliation(s)
- Tanja D Becke
- Center for Applied Tissue Engineering and Regenerative Medicine , Munich University of Applied Sciences , 80335 Munich , Germany
- Center for NanoScience , Ludwig-Maximilians-Universität München , 80799 Munich , Germany
| | - Stefan Ness
- FG Protein Biochemistry and Cellular Microbiology , Munich University of Applied Sciences , 80335 Munich , Germany
| | - Benedikt K Kaufmann
- Center for Applied Tissue Engineering and Regenerative Medicine , Munich University of Applied Sciences , 80335 Munich , Germany
- Center for NanoScience , Ludwig-Maximilians-Universität München , 80799 Munich , Germany
| | - Bastian Hartmann
- Center for Applied Tissue Engineering and Regenerative Medicine , Munich University of Applied Sciences , 80335 Munich , Germany
- Center for NanoScience , Ludwig-Maximilians-Universität München , 80799 Munich , Germany
| | - Arndt F Schilling
- Clinic for Trauma Surgery, Orthopaedics, and Plastic Surgery , University Medical Center Göttingen , 37075 Göttingen , Germany
| | - Stefanie Sudhop
- Center for Applied Tissue Engineering and Regenerative Medicine , Munich University of Applied Sciences , 80335 Munich , Germany
- Center for NanoScience , Ludwig-Maximilians-Universität München , 80799 Munich , Germany
| | - Markus Hilleringmann
- FG Protein Biochemistry and Cellular Microbiology , Munich University of Applied Sciences , 80335 Munich , Germany
| | - Hauke Clausen-Schaumann
- Center for Applied Tissue Engineering and Regenerative Medicine , Munich University of Applied Sciences , 80335 Munich , Germany
- Center for NanoScience , Ludwig-Maximilians-Universität München , 80799 Munich , Germany
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126
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Pickering AC, Vitry P, Prystopiuk V, Garcia B, Höök M, Schoenebeck J, Geoghegan JA, Dufrêne YF, Fitzgerald JR. Host-specialized fibrinogen-binding by a bacterial surface protein promotes biofilm formation and innate immune evasion. PLoS Pathog 2019; 15:e1007816. [PMID: 31216354 PMCID: PMC6602291 DOI: 10.1371/journal.ppat.1007816] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 07/01/2019] [Accepted: 05/06/2019] [Indexed: 11/18/2022] Open
Abstract
Fibrinogen is an essential part of the blood coagulation cascade and a major component of the extracellular matrix in mammals. The interface between fibrinogen and bacterial pathogens is an important determinant of the outcome of infection. Here, we demonstrate that a canine host-restricted skin pathogen, Staphylococcus pseudintermedius, produces a cell wall-associated protein (SpsL) that has evolved the capacity for high strength binding to canine fibrinogen, with reduced binding to fibrinogen of other mammalian species including humans. Binding occurs via the surface-expressed N2N3 subdomains, of the SpsL A-domain, to multiple sites in the fibrinogen α-chain C-domain by a mechanism analogous to the classical dock, lock, and latch binding model. Host-specific binding is dependent on a tandem repeat region of the fibrinogen α-chain, a region highly divergent between mammals. Of note, we discovered that the tandem repeat region is also polymorphic in different canine breeds suggesting a potential influence on canine host susceptibility to S. pseudintermedius infection. Importantly, the strong host-specific fibrinogen-binding interaction of SpsL to canine fibrinogen is essential for bacterial aggregation and biofilm formation, and promotes resistance to neutrophil phagocytosis, suggesting a key role for the interaction during pathogenesis. Taken together, we have dissected a bacterial surface protein-ligand interaction resulting from the co-evolution of host and pathogen that promotes host-specific innate immune evasion and may contribute to its host-restricted ecology. Many bacterial pathogens are specialized for a single host-species and rarely cause infections of other hosts. Our understanding of the bacterial factors underpinning host-specificity are limited. Here we demonstrate that a canine host-restricted bacterial pathogen, Staphylococcus pseudintermedius, produces a surface protein (SpsL) that has the ability to preferentially bind to canine fibrinogen with high strength. This host-specific interaction has evolved via binding to a tandem repeat region of the fibrinogen α-chain which is divergent among mammalian species. Importantly, we found that the strong binding interaction with canine fibrinogen promotes bacterial aggregation and biofilm formation as well as inhibiting neutrophil phagocytosis. Our findings reveal the host-adaptive evolution of a key bacterium-host interaction that promotes evasion of the host immune response.
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Affiliation(s)
- Amy C. Pickering
- The Roslin Institute and Edinburgh Infectious Diseases, University of Edinburgh, Easter Bush Campus, Edinburgh, Scotland, United Kingdom
| | - Pauline Vitry
- Institute of Life Sciences, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Valeriia Prystopiuk
- Institute of Life Sciences, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Brandon Garcia
- Department of Microbiology and Immunology, Brody school of Medicine, East Carolina University, Greenville, North Carolina, United States of America
| | - Magnus Höök
- Center for Infectious and Inflammatory Diseases, Texas A&M Health Science Center, Houston, Texas, United States of America
| | - Jeffrey Schoenebeck
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Edinburgh, Scotland, United Kingdom
| | - Joan A. Geoghegan
- Department of Microbiology, Moyne Institute of Preventive Medicine, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland
| | - Yves F. Dufrêne
- Institute of Life Sciences, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
- Walloon Excellence in Life Sciences and Biotechnology, Wavre, Belgium
| | - J. Ross Fitzgerald
- The Roslin Institute and Edinburgh Infectious Diseases, University of Edinburgh, Easter Bush Campus, Edinburgh, Scotland, United Kingdom
- * E-mail:
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127
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Yoon J, Kim Y, Park JW. Binary Structure of Amyloid Beta Oligomers Revealed by Dual Recognition Mapping. Anal Chem 2019; 91:8422-8428. [PMID: 31140786 DOI: 10.1021/acs.analchem.9b01316] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Amyloid beta (Aβ) oligomers are widely considered to be the causative agent of Alzheimer's disease (AD), a progressive neurodegenerative disorder. Determining the structure of oligomers is, therefore, important for understanding the disease and developing therapeutic agents; however, elucidating the structure has been proven difficult due to heterogeneity, noncrystallinity, and variability. Herein, we investigated homo- and hetero-oligomers of Aβ40 and Aβ42 using atomic force microscopy (AFM) and revealed characteristics of the molecular structure. By examining the surface of individual oligomers with sequential N- and C-terminus specific antibody-tethered tips, we simultaneously mapped the N- and C-terminus distributions and the elastic modulus. Interestingly, both the N- and C-termini of Aβ peptides were recognized on the oligomer surface, and the termini detected pixel regions exhibited a lower elastic modulus than silent pixel regions. These two types of regions were randomly distributed on the oligomer surface.
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Affiliation(s)
- Jihyun Yoon
- Department of Chemistry , Pohang University of Science and Technology , 77 Cheongam-Ro , Nam-Gu, Pohang 37673 , Republic of Korea
| | - Youngkyu Kim
- Department of Chemistry , Pohang University of Science and Technology , 77 Cheongam-Ro , Nam-Gu, Pohang 37673 , Republic of Korea
| | - Joon Won Park
- Department of Chemistry , Pohang University of Science and Technology , 77 Cheongam-Ro , Nam-Gu, Pohang 37673 , Republic of Korea
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128
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Sedlak SM, Schendel LC, Melo MCR, Pippig DA, Luthey-Schulten Z, Gaub HE, Bernardi RC. Direction Matters: Monovalent Streptavidin/Biotin Complex under Load. NANO LETTERS 2019; 19:3415-3421. [PMID: 30346175 PMCID: PMC6486461 DOI: 10.1021/acs.nanolett.8b04045] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Novel site-specific attachment strategies combined with improvements of computational resources enable new insights into the mechanics of the monovalent biotin/streptavidin complex under load and forced us to rethink the diversity of rupture forces reported in the literature. We discovered that the mechanical stability of this complex depends strongly on the geometry in which force is applied. By atomic force microscopy-based single molecule force spectroscopy we found unbinding of biotin to occur beyond 400 pN at force loading rates of 10 nN/s when monovalent streptavidin was tethered at its C-terminus. This value is about twice as high than that for N-terminal attachment. Steered molecular dynamics simulations provided a detailed picture of the mechanics of the unbinding process in the corresponding force loading geometries. Using machine learning techniques, we connected findings from hundreds of simulations to the experimental results, identifying different force propagation pathways. Interestingly, we observed that depending on force loading geometry, partial unfolding of N-terminal region of monovalent streptavidin occurs before biotin is released from the binding pocket.
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Affiliation(s)
- Steffen M. Sedlak
- Lehrstuhl für Angewandte Physik and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Amalienstr. 54, 80799 Munich, Germany
| | - Leonard C. Schendel
- Lehrstuhl für Angewandte Physik and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Amalienstr. 54, 80799 Munich, Germany
| | - Marcelo C. R. Melo
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Diana A. Pippig
- Lehrstuhl für Angewandte Physik and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Amalienstr. 54, 80799 Munich, Germany
| | - Zaida Luthey-Schulten
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Hermann E. Gaub
- Lehrstuhl für Angewandte Physik and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Amalienstr. 54, 80799 Munich, Germany
| | - Rafael C. Bernardi
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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129
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Abstract
The main strategies used by pathogenic bacteria to infect eukaryotic tissue include their adherence to cells and the extracellular matrix (ECM), the subsequent colonization and invasion as well as the evasion of immune defences. A variety of structurally and functionally characterized adhesins and binding proteins of gram-positive bacteria facilitate these processes by specifically recognizing and interacting with various components of the host ECM, including different collagens, fibronectin and other macromolecules. The ECM affects the cellular physiology of our body and is critical for adhesion, migration, proliferation, and differentiation of many host cell types, but also provides the support for infiltrating pathogens, particularly under conditions of injury and trauma. Moreover, microbial binding to a variety of adhesive components in host tissue fluids leads to structural and/or functional alterations of host proteins and to the activation of cellular mechanisms that influence tissue and cell invasion of pathogens. Since the diverse interactions of gram-positive bacteria with the ECM represent important pathogenicity mechanisms, their characterization not only allows a better understanding of microbial invasion but also provides clues for the design of novel therapeutic strategies to manage infectious diseases.
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130
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Jöhr R, Bauer MS, Schendel LC, Kluger C, Gaub HE. Dronpa: A Light-Switchable Fluorescent Protein for Opto-Biomechanics. NANO LETTERS 2019; 19:3176-3181. [PMID: 30912662 DOI: 10.1021/acs.nanolett.9b00639] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Since the development of the green fluorescent protein, fluorescent proteins (FP) are indispensable tools in molecular biology. Some FPs change their structure under illumination, which affects their interaction with other biomolecules or proteins. In particular, FPs that are able to form switchable dimers became an important tool in the field of optogenetics. They are widely used for the investigation of signaling pathways, the control of surface recruitment, as well as enzyme and gene regulation. However, optogenetics did not yet develop tools for the investigation of biomechanical processes. This could be leveraged if one could find a light-switchable FP dimer that is able to withstand sufficiently high forces. In this work, we measure the rupture force of the switchable interface in pdDronpa1.2 dimers using atomic force microscopy-based single molecule force spectroscopy. The most probable dimer rupture force amounts to around 80 pN at a pulling speed of 1600 nm/s. After switching of the dimer using illumination at 488 nm, there are hardly any measurable interface interactions, which indicates the successful dissociation of the dimers. Hence this Dronpa dimer could expand the current toolbox in optogenetics with new opto-biomechanical applications like the control of tension in adhesion processes.
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Affiliation(s)
- Res Jöhr
- Lehrstuhl für Angewandte Physik and Center for Nanoscience , Ludwig-Maximilians-Universität , Munich 80799 , Germany
| | - Magnus S Bauer
- Lehrstuhl für Angewandte Physik and Center for Nanoscience , Ludwig-Maximilians-Universität , Munich 80799 , Germany
| | - Leonard C Schendel
- Lehrstuhl für Angewandte Physik and Center for Nanoscience , Ludwig-Maximilians-Universität , Munich 80799 , Germany
| | - Carleen Kluger
- Lehrstuhl für Angewandte Physik and Center for Nanoscience , Ludwig-Maximilians-Universität , Munich 80799 , Germany
| | - Hermann E Gaub
- Lehrstuhl für Angewandte Physik and Center for Nanoscience , Ludwig-Maximilians-Universität , Munich 80799 , Germany
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131
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Binding of Staphylococcus aureus Protein A to von Willebrand Factor Is Regulated by Mechanical Force. mBio 2019; 10:mBio.00555-19. [PMID: 31040240 PMCID: PMC6495375 DOI: 10.1128/mbio.00555-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Staphylococcus aureus protein A (SpA) binds to von Willebrand factor (vWF) under flow. While vWF binding to SpA plays a role in S. aureus adherence to platelets and endothelial cells under shear stress, the molecular basis of this stress-dependent interaction has not yet been elucidated. Here we show that the SpA-vWF interaction is regulated by a new force-dependent mechanism. The results suggest that mechanical extension of vWF may lead to the exposure of a high-affinity cryptic SpA-binding site, consistent with the shear force-controlled functions of vWF. Moreover, strong binding may be promoted by force-induced structural changes in the SpA domains. This study highlights the role of mechanoregulation in controlling the adhesion of S. aureus and shows promise for the design of small inhibitors capable of blocking colonization under high shear stress. Binding of Staphylococcus aureus to the large plasma glycoprotein von Willebrand factor (vWF) is controlled by hydrodynamic flow conditions. Currently, we know little about the molecular details of this shear-stress-dependent interaction. Using single-molecule atomic force microscopy, we demonstrate that vWF binds to the S. aureus surface protein A (SpA) via a previously undescribed force-sensitive mechanism. We identify an extremely strong SpA-vWF interaction, capable of withstanding forces of ∼2 nN, both in laboratory and in clinically relevant methicillin-resistant S. aureus (MRSA) strains. Strong bonds are activated by mechanical stress, consistent with flow experiments revealing that bacteria adhere in larger amounts to vWF surfaces when the shear rate is increased. We suggest that force-enhanced adhesion may involve conformational changes in vWF. Under force, elongation of vWF may lead to the exposure of a high-affinity cryptic SpA-binding site to which bacteria firmly attach. In addition, force-induced structural changes in the SpA domains may also promote strong, high-affinity binding. This force-regulated interaction might be of medical importance as it may play a role in bacterial adherence to platelets and to damaged blood vessels.
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Nanoscale imaging reveals miRNA-mediated control of functional states of dendritic spines. Proc Natl Acad Sci U S A 2019; 116:9616-9621. [PMID: 31019087 DOI: 10.1073/pnas.1819374116] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Dendritic spines are major loci of excitatory inputs and undergo activity-dependent structural changes that contribute to synaptic plasticity and memory formation. Despite the existence of various classification types of spines, how they arise and which molecular components trigger their structural plasticity remain elusive. microRNAs (miRNAs) have emerged as critical regulators of synapse development and plasticity via their control of gene expression. Brain-specific miR-134s likely regulate the morphological maturation of spines, but their subcellular distributions and functional impacts have rarely been assessed. Here, we exploited atomic force microscopy to visualize in situ miR-134s, which indicated that they are mainly distributed at nearby dendritic shafts and necks of spines. The abundance of miR-134s varied between morphologically and functionally distinct spine types, and their amounts were inversely correlated with their postulated maturation stages. Moreover, spines exhibited reduced contents of miR-134s when selectively stimulated with beads containing brain-derived neurotropic factor (BDNF). Taken together, in situ visualizations of miRNAs provided unprecedented insights into the "inverse synaptic-tagging" roles of miR-134s that are selective to inactive/irrelevant synapses and potentially a molecular means for modifying synaptic connectivity via structural alteration.
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133
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Yu C, Zhang D, Feng X, Chai Y, Lu P, Li Q, Feng F, Wang X, Li Y. Nanoprobe-based force spectroscopy as a versatile platform for probing the mechanical adhesion of bacteria. NANOSCALE 2019; 11:7648-7655. [PMID: 30720812 DOI: 10.1039/c8nr10338k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The first stage of biofilm-associated infections is commonly caused by initial adhesion of bacteria to intravascular tubes, catheters and other medical devices. The overuse of antibiotics to treat these infections has led to the spread of antibiotic resistance, which has made infections difficult to eradicate. It is crucial to develop advanced strategies to inhibit biofilm formation, avoiding the emergence of antibiotic resistance. Previously, it has been reported that substrate stiffness plays an important role in the initial attachment of bacteria. However, the mechanism of how the stiffness modulates the initial adhesion of bacteria remains unclear. Here, we developed magnetic nanoprobe-based force-induced remnant magnetization spectroscopy (FIRMS) as a new platform to measure the adhesion force of bacteria. Through examining the initial adhesion force and the adhesive protein, fibronectin-binding protein (FnBP), of Staphylococcus aureus (S. aureus), we found that the increase of the substrate stiffness promoted the expression of FnBP, thus enhancing the initial adhesion force of bacteria. Following the formation of initial adhesion, the substrates with soft stiffness delayed the biofilm formation, whereas those with moderate stiffness showed preferential promotion of the biofilm formation. We expect this versatile platform to be beneficial to the study of adhesion behaviors of bacteria that sheds light on the design of new medical materials to treat microbial infections.
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Affiliation(s)
- Chanchan Yu
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Beijing 100190, China.
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134
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Delparastan P, Malollari KG, Lee H, Messersmith PB. Direct Evidence for the Polymeric Nature of Polydopamine. Angew Chem Int Ed Engl 2019; 58:1077-1082. [PMID: 30485624 PMCID: PMC6424361 DOI: 10.1002/anie.201811763] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 11/18/2018] [Indexed: 11/07/2022]
Abstract
Inspired by the adhesive proteins of mussels, polydopamine (pDA) has emerged as one of the most widely employed materials for surface functionalization. Despite numerous attempts at characterization, little consensus has emerged regarding whether pDA is a covalent polymer or a noncovalent aggregate of low molecular weight species. Here, we employed single-molecule force spectroscopy (SMFS) to characterize pDA films. Retraction of a pDA-coated cantilever from an oxide surface shows the characteristic features of a polymer with contour lengths of up to 200 nm. pDA polymers are generally weakly bound to the surface through much of their contour length, with occasional "sticky" points. Our findings represent the first direct evidence for the polymeric nature of pDA and provide a foundation upon which to better understand and tailor its physicochemical properties.
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Affiliation(s)
- Peyman Delparastan
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720-1760 (USA),
| | | | - Haeshin Lee
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea
| | - Phillip B. Messersmith
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720-1760 (USA),
- Department of Bioengineering, University of California, Berkeley and Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley
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135
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Erlich KR, Sedlak SM, Jobst MA, Milles LF, Gaub HE. DNA-free directed assembly in single-molecule cut-and-paste. NANOSCALE 2019; 11:407-411. [PMID: 30604815 DOI: 10.1039/c8nr08636b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Single-molecule cut-and-paste facilitates bottom-up directed assembly of nanoscale biomolecular networks in defined geometries and enables analysis with spatio-temporal resolution. However, arrangement of diverse molecules of interest requires versatile handling systems. The novel DNA-free, genetically encodable scheme described here utilises an orthogonal handling strategy to promote arrangement of enzymes and enzyme networks.
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Affiliation(s)
- Katherine R Erlich
- Lehrstuhl für Angewandte Physik and Center for NanoScience, Ludwig-Maximilians-Universität München, Amalienstr. 54, 80799 München, Germany.
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136
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Delparastan P, Malollari KG, Lee H, Messersmith PB. Direct Evidence for the Polymeric Nature of Polydopamine. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201811763] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Peyman Delparastan
- Department of Materials Science and EngineeringUniversity of California, Berkeley Berkeley CA 94720-1760 USA
| | | | - Haeshin Lee
- Department of ChemistryKorea Advanced Institute of Science and Technology (KAIST) Daejeon South Korea
| | - Phillip B. Messersmith
- Department of Materials Science and EngineeringUniversity of California, Berkeley Berkeley CA 94720-1760 USA
- Department of BioengineeringUniversity of California Berkeley USA
- Materials Science DivisionLawrence Berkeley National Laboratory, Berkeley USA
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137
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Milles LF, Unterauer EM, Nicolaus T, Gaub HE. Calcium stabilizes the strongest protein fold. Nat Commun 2018; 9:4764. [PMID: 30420680 PMCID: PMC6232131 DOI: 10.1038/s41467-018-07145-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 10/17/2018] [Indexed: 12/21/2022] Open
Abstract
Staphylococcal pathogens adhere to their human targets with exceptional resilience to mechanical stress, some propagating force to the bacterium via small, Ig-like folds called B domains. We examine the mechanical stability of these folds using atomic force microscopy-based single-molecule force spectroscopy. The force required to unfold a single B domain is larger than 2 nN – the highest mechanostability of a protein to date by a large margin. B domains coordinate three calcium ions, which we identify as crucial for their extreme mechanical strength. When calcium is removed through chelation, unfolding forces drop by a factor of four. Through systematic mutations in the calcium coordination sites we can tune the unfolding forces from over 2 nN to 0.15 nN, and dissect the contribution of each ion to B domain mechanostability. Their extraordinary strength, rapid refolding and calcium-tunable force response make B domains interesting protein design targets. Staphylococcal pathogens adhere to their human targets using adhesins, which can withstand extremely high forces. Here, authors use single-molecule force spectroscopy to determine the similarly high unfolding forces of B domains that link the adhesin to the bacterium.
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Affiliation(s)
- Lukas F Milles
- Lehrstuhl für Angewandte Physik and Center for Nanoscience, Ludwig-Maximilians-University, Amalienstr. 54, 80799, Munich, Germany.
| | - Eduard M Unterauer
- Lehrstuhl für Angewandte Physik and Center for Nanoscience, Ludwig-Maximilians-University, Amalienstr. 54, 80799, Munich, Germany
| | - Thomas Nicolaus
- Lehrstuhl für Angewandte Physik and Center for Nanoscience, Ludwig-Maximilians-University, Amalienstr. 54, 80799, Munich, Germany
| | - Hermann E Gaub
- Lehrstuhl für Angewandte Physik and Center for Nanoscience, Ludwig-Maximilians-University, Amalienstr. 54, 80799, Munich, Germany.
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138
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Yang P, Song Y, Feng W, Zhang W. Unfolding of a Single Polymer Chain from the Single Crystal by Air-Phase Single-Molecule Force Spectroscopy: Toward Better Force Precision and More Accurate Description of Molecular Behaviors. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01544] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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139
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Becke TD, Ness S, Sudhop S, Gaub HE, Hilleringmann M, Schilling AF, Clausen-Schaumann H. Covalent Immobilization of Proteins for the Single Molecule Force Spectroscopy. J Vis Exp 2018. [PMID: 30176022 PMCID: PMC6128213 DOI: 10.3791/58167] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
In recent years, atomic force microscopy (AFM) based single molecule force spectroscopy (SMFS) extended our understanding of molecular properties and functions. It gave us the opportunity to explore a multiplicity of biophysical mechanisms, e.g., how bacterial adhesins bind to host surface receptors in more detail. Among other factors, the success of SMFS experiments depends on the functional and native immobilization of the biomolecules of interest on solid surfaces and AFM tips. Here, we describe a straightforward protocol for the covalent coupling of proteins to silicon surfaces using silane-PEG-carboxyls and the well-established N-hydroxysuccinimid/1-ethyl-3-(3-dimethyl-aminopropyl)carbodiimid (EDC/NHS) chemistry in order to explore the interaction of pilus-1 adhesin RrgA from the Gram-positive bacterium Streptococcus pneumoniae (S. pneumoniae) with the extracellular matrix protein fibronectin (Fn). Our results show that the surface functionalization leads to a homogenous distribution of Fn on the glass surface and to an appropriate concentration of RrgA on the AFM cantilever tip, apparent by the target value of up to 20% of interaction events during SMFS measurements and revealed that RrgA binds to Fn with a mean force of 52 pN. The protocol can be adjusted to couple via site specific free thiol groups. This results in a predefined protein or molecule orientation and is suitable for other biophysical applications besides the SMFS.
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Affiliation(s)
- Tanja D Becke
- Center for Applied Tissue Engineering and Regenerative Medicine, Munich University of Applied Sciences; FG Protein Biochemistry & Cellular Microbiology, Munich University of Applied Sciences; Center for Nano Science, Ludwig-Maximilians-Universität München;
| | - Stefan Ness
- FG Protein Biochemistry & Cellular Microbiology, Munich University of Applied Sciences
| | - Stefanie Sudhop
- Center for Applied Tissue Engineering and Regenerative Medicine, Munich University of Applied Sciences; Center for Nano Science, Ludwig-Maximilians-Universität München
| | - Hermann E Gaub
- Center for Nano Science, Ludwig-Maximilians-Universität München
| | - Markus Hilleringmann
- FG Protein Biochemistry & Cellular Microbiology, Munich University of Applied Sciences
| | - Arndt F Schilling
- Klinik für Unfallchirurgie, Orthopädie und Plastische Chirurgie, University Medical Center Göttingen
| | - Hauke Clausen-Schaumann
- Center for Applied Tissue Engineering and Regenerative Medicine, Munich University of Applied Sciences; Center for Nano Science, Ludwig-Maximilians-Universität München
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140
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Mechanical architecture and folding of E. coli type 1 pilus domains. Nat Commun 2018; 9:2758. [PMID: 30013059 PMCID: PMC6048123 DOI: 10.1038/s41467-018-05107-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 05/03/2018] [Indexed: 12/16/2022] Open
Abstract
Uropathogenic Escherichia coli attach to tissues using pili type 1. Each pilus is composed by thousands of coiled FimA domains followed by the domains of the tip fibrillum, FimF-FimG-FimH. The domains are linked by non-covalent β-strands that must resist mechanical forces during attachment. Here, we use single-molecule force spectroscopy to measure the mechanical contribution of each domain to the stability of the pilus and monitor the oxidative folding mechanism of a single Fim domain assisted by periplasmic FimC and the oxidoreductase DsbA. We demonstrate that pilus domains bear high mechanical stability following a hierarchy by which domains close to the tip are weaker than those close to or at the pilus rod. During folding, this remarkable stability is achieved by the intervention of DsbA that not only forms strategic disulfide bonds but also serves as a chaperone assisting the folding of the domains. The pilus type 1 of uropathogenic E. coli must resist mechanical forces to remain attached to the epithelium. Here the authors use single-molecule force spectroscopy to demonstrate a hierarchy of mechanical stability among the pilus domains and show that the oxidoreductase DsbA also acts as a folding chaperone on the domains.
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141
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Mechanomicrobiology: How Mechanical Forces Activate Staphylococcus aureus Adhesion. Trends Microbiol 2018; 26:645-648. [PMID: 29866473 DOI: 10.1016/j.tim.2018.05.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 05/08/2018] [Accepted: 05/09/2018] [Indexed: 01/30/2023]
Abstract
During colonization of biomaterials and host tissues, surface-attached bacteria are subjected to mechanical stresses, including hydrodynamic flow and cell-surface contacts. Two publications show that mechanical force activates the adhesive function of Staphylococcus aureus surface proteins, thereby providing the pathogen with a means to withstand high shear stress during colonization.
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142
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Staphylococcus aureus clumping factor A is a force-sensitive molecular switch that activates bacterial adhesion. Proc Natl Acad Sci U S A 2018; 115:5564-5569. [PMID: 29735708 PMCID: PMC6003445 DOI: 10.1073/pnas.1718104115] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The Staphylococcus aureus surface protein clumping factor A (ClfA) binds to the blood plasma protein fibrinogen (Fg) via molecular interactions that are poorly understood. Here, we unravel the forces guiding the interaction between ClfA and immobilized Fg, showing that it is dramatically enhanced by tensile loading. Our findings favor a model whereby ClfA interacts with Fg via two distinct binding sites, the adhesive function of which is tightly regulated by mechanical force. Reminiscent of a catch bond mechanism, this force-enhanced adhesion explains the ability of ClfA to promote S. aureus colonization of host tissues and biomedical devices under physical stress. Clumping factor A (ClfA), a cell-wall–anchored protein from Staphylococcus aureus, is a virulence factor in various infections and facilitates the colonization of protein-coated biomaterials. ClfA promotes bacterial adhesion to the blood plasma protein fibrinogen (Fg) via molecular forces that have not been studied so far. A unique, yet poorly understood, feature of ClfA is its ability to favor adhesion to Fg at high shear stress. Unraveling the strength and dynamics of the ClfA–Fg interaction would help us better understand how S. aureus colonizes implanted devices and withstands physiological shear stress. By means of single-molecule experiments, we show that ClfA behaves as a force-sensitive molecular switch that potentiates staphylococcal adhesion under mechanical stress. The bond between ClfA and immobilized Fg is weak (∼0.1 nN) at low tensile force, but is dramatically enhanced (∼1.5 nN) by mechanical tension, as observed with catch bonds. Strong bonds, but not weak ones, are inhibited by a peptide mimicking the C-terminal segment of the Fg γ-chain. These results point to a model whereby ClfA interacts with Fg via two distinct binding sites, the adhesive function of which is regulated by mechanical tension. This force-activated mechanism is of biological significance because it explains at the molecular level the ability of ClfA to promote bacterial attachment under high physiological shear stress.
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143
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Pawluk A. Breaking the Rules. Cell 2018; 173:805-807. [PMID: 29727666 DOI: 10.1016/j.cell.2018.04.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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144
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Affiliation(s)
- Philippe Herman-Bausier
- Institute of Life Sciences, Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Yves F Dufrêne
- Institute of Life Sciences, Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium. .,Walloon Excellence in Life Sciences and Biotechnology (WELBIO), 1300 Wavre, Belgium
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