1
|
Lin AJ, Sihorwala AZ, Belardi B. Engineering Tissue-Scale Properties with Synthetic Cells: Forging One from Many. ACS Synth Biol 2023; 12:1889-1907. [PMID: 37417657 PMCID: PMC11017731 DOI: 10.1021/acssynbio.3c00061] [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] [Indexed: 07/08/2023]
Abstract
In metazoans, living cells achieve capabilities beyond individual cell functionality by assembling into multicellular tissue structures. These higher-order structures represent dynamic, heterogeneous, and responsive systems that have evolved to regenerate and coordinate their actions over large distances. Recent advances in constructing micrometer-sized vesicles, or synthetic cells, now point to a future where construction of synthetic tissue can be pursued, a boon to pressing material needs in biomedical implants, drug delivery systems, adhesives, filters, and storage devices, among others. To fully realize the potential of synthetic tissue, inspiration has been and will continue to be drawn from new molecular findings on its natural counterpart. In this review, we describe advances in introducing tissue-scale features into synthetic cell assemblies. Beyond mere complexation, synthetic cells have been fashioned with a variety of natural and engineered molecular components that serve as initial steps toward morphological control and patterning, intercellular communication, replication, and responsiveness in synthetic tissue. Particular attention has been paid to the dynamics, spatial constraints, and mechanical strengths of interactions that drive the synthesis of this next-generation material, describing how multiple synthetic cells can act as one.
Collapse
Affiliation(s)
- Alexander J Lin
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Ahmed Z Sihorwala
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
| | - Brian Belardi
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
| |
Collapse
|
2
|
Molecular Recognition of Proteins through Quantitative Force Maps at Single Molecule Level. Biomolecules 2022; 12:biom12040594. [PMID: 35454182 PMCID: PMC9024611 DOI: 10.3390/biom12040594] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 04/08/2022] [Accepted: 04/14/2022] [Indexed: 12/24/2022] Open
Abstract
Intermittent jumping force is an operational atomic-force microscopy mode that produces simultaneous topography and tip-sample maximum-adhesion images based on force spectroscopy. In this work, the operation conditions have been implemented scanning in a repulsive regime and applying very low forces, thus avoiding unspecific tip-sample forces. Remarkably, adhesion images give only specific rupture events, becoming qualitative and quantitative molecular recognition maps obtained at reasonably fast rates, which is a great advantage compared to the force–volume modes. This procedure has been used to go further in discriminating between two similar protein molecules, avidin and streptavidin, in hybrid samples. The adhesion maps generated scanning with biotinylated probes showed features identified as avidin molecules, in the range of 40–80 pN; meanwhile, streptavidin molecules rendered 120–170 pN at the selected working conditions. The gathered results evidence that repulsive jumping force mode applying very small forces allows the identification of biomolecules through the specific rupture forces of the complexes and could serve to identify receptors on membranes or samples or be applied to design ultrasensitive detection technologies.
Collapse
|
3
|
Single-particle chemical force microscopy to characterize virus surface chemistry. Biotechniques 2020; 69:363-370. [DOI: 10.2144/btn-2020-0085] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Two important viral surface characteristics are the hydrophobicity and surface charge, which determine the viral colloidal behavior and mobility. Chemical force microscopy allows the detection of viral surface chemistry in liquid samples with small amounts of virus sample. This single-particle method requires the functionalization of an atomic force microscope (AFM) probe and covalent bonding of viruses to a surface. A hydrophobic methyl-modified AFM probe was used to study the viral surface hydrophobicity, and an AFM probe terminated with either negatively charged carboxyl acid or positively charged quaternary amine was used to study the viral surface charge. With an understanding of viral surface properties, the way in which viruses interact with the environment can be better predicted.
Collapse
|
4
|
Elias-Mordechai M, Chetrit E, Berkovich R. Interplay between Viscoelasticity and Force Rate Affects Sequential Unfolding in Polyproteins Pulled at Constant Velocity. Macromolecules 2020; 53:3021-3029. [PMID: 32905266 PMCID: PMC7467765 DOI: 10.1021/acs.macromol.0c00278] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 03/30/2020] [Indexed: 11/30/2022]
Abstract
![]()
Polyproteins are
unique constructs, comprised of folded protein
domains in tandem and polymeric linkers. These macromolecules perform
under biological stresses by modulating their response through partial
unfolding and extending. Although these unfolding events are considered
independent, a history dependence of forced unfolding within polyproteins
was reported. Here we measure the unfolding of single poly(I91) octamers,
complemented with Brownian dynamics simulations, displaying increasing
hierarchy in unfolding-foces, accompanied by a decrease in the effective
stiffness. This counters the existing understanding that relates stiffness
with variations in domain size and probe stiffness, which is expected
to reduce the unfolding forces with every consecutive unfolding event.
We utilize a simple mechanistic viscoelastic model to show that two
effects are combined within a sequential forced unfolding process:
the viscoelastic properties of the growing linker chain lead to a
hierarchy of the unfolding events, and force-rate application governs
the unfolding kinetics.
Collapse
Affiliation(s)
- Moran Elias-Mordechai
- Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Einat Chetrit
- Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Ronen Berkovich
- Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel.,The Ilze Katz Institute for Nanoscience and Technology, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| |
Collapse
|
5
|
Schmidt S, Paul TJ, Strzelczyk AK. Interactive Polymer Gels as Biomimetic Sensors for Carbohydrate Interactions and Capture–Release Devices for Pathogens. MACROMOL CHEM PHYS 2019. [DOI: 10.1002/macp.201900323] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Stephan Schmidt
- Institute of Organic and Macromolecular ChemistryHeinrich‐Heine‐University Düsseldorf Universitätsstraße 1 40225 Dusseldorf Germany
| | - Tanja Janine Paul
- Institute of Organic and Macromolecular ChemistryHeinrich‐Heine‐University Düsseldorf Universitätsstraße 1 40225 Dusseldorf Germany
| | - Alexander Klaus Strzelczyk
- Institute of Organic and Macromolecular ChemistryHeinrich‐Heine‐University Düsseldorf Universitätsstraße 1 40225 Dusseldorf Germany
| |
Collapse
|
6
|
Camaleño de la Calle A, Gerke C, Chang XJ, Grafmüller A, Hartmann L, Schmidt S. Multivalent Interactions of Polyamide Based Sequence‐Controlled Glycomacromolecules with Concanavalin A. Macromol Biosci 2019; 19:e1900033. [DOI: 10.1002/mabi.201900033] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 03/21/2019] [Indexed: 01/08/2023]
Affiliation(s)
- Alberto Camaleño de la Calle
- Institute of Organic and Macromolecular ChemistryHeinrich‐Heine‐University Düsseldorf, Universitatsstraße 1 40225 Dusseldorf Germany
| | - Christoph Gerke
- Institute of Organic and Macromolecular ChemistryHeinrich‐Heine‐University Düsseldorf, Universitatsstraße 1 40225 Dusseldorf Germany
| | - Xi Jeffrey Chang
- Institute of Organic and Macromolecular ChemistryHeinrich‐Heine‐University Düsseldorf, Universitatsstraße 1 40225 Dusseldorf Germany
| | - Andrea Grafmüller
- Department of Theory and Bio‐SystemsMax Planck Institute of Colloids and Interfaces Am Mühlenberg 1 14478 Potsdam Germany
| | - Laura Hartmann
- Institute of Organic and Macromolecular ChemistryHeinrich‐Heine‐University Düsseldorf, Universitatsstraße 1 40225 Dusseldorf Germany
| | - Stephan Schmidt
- Institute of Organic and Macromolecular ChemistryHeinrich‐Heine‐University Düsseldorf, Universitatsstraße 1 40225 Dusseldorf Germany
| |
Collapse
|
7
|
Ebner A, Wildling L, Gruber HJ. Functionalization of AFM Tips and Supports for Molecular Recognition Force Spectroscopy and Recognition Imaging. Methods Mol Biol 2019; 1886:117-151. [PMID: 30374865 DOI: 10.1007/978-1-4939-8894-5_7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Linking of sensor molecules (e.g., antibodies) to an AFM tip converts it into a biosensor by which single target molecules (e.g., antigens) can be detected and localized on the sample surface. Moreover, the mechanism of interaction can be studied by force spectroscopy if purified target molecules are linked to an ultra-flat surface, such as mica or silicon (nitride). Rapid imaging of the binding sites and force spectroscopy studies are greatly facilitated if 6-10 nm long polyethylene glycol (PEG) chains are used as flexible tethers between the sensor molecule and the tip. Here, we describe a set of methods by which a variety of proteins, oligonucleotides, or small molecules can be tethered to silicon (nitride) tips or to mica. Methods are included which afford site-specific and oriented coupling of the sensor molecules.
Collapse
Affiliation(s)
- A Ebner
- Institute of Biophysics, Johannes Kepler University Linz, Linz, Austria
| | - L Wildling
- Institute of Biophysics, Johannes Kepler University Linz, Linz, Austria
| | - H J Gruber
- Institute of Biophysics, Johannes Kepler University Linz, Linz, Austria.
| |
Collapse
|
8
|
|
9
|
Walsh-Korb Z, Yu Y, Janeček ER, Lan Y, Del Barrio J, Williams PE, Zhang X, Scherman OA. Single-Molecule Force Spectroscopy Quantification of Adhesive Forces in Cucurbit[8]Uril Host-Guest Ternary Complexes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:1343-1350. [PMID: 28055217 DOI: 10.1021/acs.langmuir.6b03457] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Cucurbit[8]uril (CB[8]) heteroternary complexes display certain characteristics making them well-suited for molecular level adhesives. In particular, careful choice of host-guest binding pairs enables specific, fully reversible adhesion. Understanding the effect of the environment is also critical when developing new molecular level adhesives. Here we explore the binding forces involved in the methyl viologen·CB[8]·naphthol heteroternary complex using single-molecule force spectroscopy (SMFS) under a variety of conditions. From SMFS, the interaction of a single ternary complex was found to be in the region of 140 pN. Additionally, a number of surface interactions could be readily differentiated using the SMFS technique allowing for a deeper understanding of the dynamic heteroternary CB[8] system on the single-molecule scale.
Collapse
Affiliation(s)
- Zarah Walsh-Korb
- Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Ying Yu
- Department of Chemistry, Tsinghua University , Beijing 100084, China
| | - Emma-Rose Janeček
- Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Yang Lan
- Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Jesús Del Barrio
- Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Paul E Williams
- Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Xi Zhang
- Department of Chemistry, Tsinghua University , Beijing 100084, China
| | - Oren A Scherman
- Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| |
Collapse
|
10
|
Gerke C, Ebbesen MF, Jansen D, Boden S, Freichel T, Hartmann L. Sequence-Controlled Glycopolymers via Step-Growth Polymerization of Precision Glycomacromolecules for Lectin Receptor Clustering. Biomacromolecules 2017; 18:787-796. [PMID: 28117986 DOI: 10.1021/acs.biomac.6b01657] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A versatile approach for the synthesis of sequence-controlled multiblock copolymers, using a combination of solid phase synthesis and step-growth polymerization by photoinduced thiol-ene coupling (TEC) is presented. Following this strategy, a series of sequence-controlled glycopolymers is derived from the polymerization of a hydrophilic spacer macromonomer and different glycomacromonomers bearing between one to five α-d-Mannose (Man) ligands. Through the solid phase assembly of the macromonomers, the number and positioning of spacer and sugar moieties is controlled and translates into the sequence-control of the final polymer. A maximum M̅n of 16 kDa, corresponding to a X̅n of 10, for the applied macromonomers is accessible with optimized polymerization conditions. The binding behavior of the resulting multiblock glycopolymers toward the model lectin Concanavalin A (ConA) is studied via turbidity assays and surface plasmon resonance (SPR) measurements, comparing the ability of precision glycomacromolecules and glycopolymers to bind to and cross-link ConA in dependence of the number of sugar moieties and overall molecular weight. The results show that there is a clear correlation between number of Man ligands and Con A binding and clustering, whereas the length of the glycooligomer- or polymer backbone seems to have no effect.
Collapse
Affiliation(s)
- Christoph Gerke
- Institute of Organic and Macromolecular Chemistry, Heinrich-Heine-University Düsseldorf , Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Morten F Ebbesen
- Institute of Organic and Macromolecular Chemistry, Heinrich-Heine-University Düsseldorf , Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Dennis Jansen
- Institute of Organic and Macromolecular Chemistry, Heinrich-Heine-University Düsseldorf , Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Sophia Boden
- Institute of Organic and Macromolecular Chemistry, Heinrich-Heine-University Düsseldorf , Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Tanja Freichel
- Institute of Organic and Macromolecular Chemistry, Heinrich-Heine-University Düsseldorf , Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Laura Hartmann
- Institute of Organic and Macromolecular Chemistry, Heinrich-Heine-University Düsseldorf , Universitätsstraße 1, 40225 Düsseldorf, Germany
| |
Collapse
|
11
|
Signorelli S, Santini S, Yamada T, Bizzarri AR, Beattie CW, Cannistraro S. Binding of Amphipathic Cell Penetrating Peptide p28 to Wild Type and Mutated p53 as studied by Raman, Atomic Force and Surface Plasmon Resonance spectroscopies. Biochim Biophys Acta Gen Subj 2017; 1861:910-921. [PMID: 28126403 DOI: 10.1016/j.bbagen.2017.01.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 12/21/2016] [Accepted: 01/20/2017] [Indexed: 10/20/2022]
Abstract
BACKGROUND Mutations within the DNA binding domain (DBD) of the tumor suppressor p53 are found in >50% of human cancers and may significantly modify p53 secondary structure impairing its function. p28, an amphipathic cell-penetrating peptide, binds to the DBD through hydrophobic interaction and induces a posttranslational increase in wildtype and mutant p53 restoring functionality. We use mutation analyses to explore which elements of secondary structure may be critical to p28 binding. METHODS Molecular modeling, Raman spectroscopy, Atomic Force Spectroscopy (AFS) and Surface Plasmon Resonance (SPR) were used to identify which secondary structure of site-directed and naturally occurring mutant DBDs are potentially altered by discrete changes in hydrophobicity and the molecular interaction with p28. RESULTS We show that specific point mutations that alter hydrophobicity within non-mutable and mutable regions of the p53 DBD alter specific secondary structures. The affinity of p28 was positively correlated with the β-sheet content of a mutant DBD, and reduced by an increase in unstructured or random coil that resulted from a loss in hydrophobicity and redistribution of surface charge. CONCLUSIONS These results help refine our knowledge of how mutations within p53-DBD alter secondary structure and provide insight on how potential structural alterations in p28 or similar molecules improve their ability to restore p53 function. GENERAL SIGNIFICANCE Raman spectroscopy, AFS, SPR and computational modeling are useful approaches to characterize how mutations within the p53DBD potentially affect secondary structure and identify those structural elements prone to influence the binding affinity of agents designed to increase the functionality of p53.
Collapse
Affiliation(s)
- Sara Signorelli
- Biophysics and Nanoscience Centre, DEB, Università della Tuscia, Viterbo, Italy; Department of Science, University Roma Tre, Rome, Italy
| | - Simona Santini
- Biophysics and Nanoscience Centre, DEB, Università della Tuscia, Viterbo, Italy
| | - Tohru Yamada
- Department of Surgery, Division of Surgical Oncology, University of Illinois College of Medicine, Chicago, IL, USA
| | - Anna Rita Bizzarri
- Biophysics and Nanoscience Centre, DEB, Università della Tuscia, Viterbo, Italy.
| | - Craig W Beattie
- Department of Surgery, Division of Surgical Oncology, University of Illinois College of Medicine, Chicago, IL, USA
| | | |
Collapse
|
12
|
Bano F, Banerji S, Howarth M, Jackson DG, Richter RP. A single molecule assay to probe monovalent and multivalent bonds between hyaluronan and its key leukocyte receptor CD44 under force. Sci Rep 2016; 6:34176. [PMID: 27679982 PMCID: PMC5040960 DOI: 10.1038/srep34176] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 09/08/2016] [Indexed: 01/31/2023] Open
Abstract
Glycosaminoglycans (GAGs), a category of linear, anionic polysaccharides, are ubiquitous in the extracellular space, and important extrinsic regulators of cell function. Despite the recognized significance of mechanical stimuli in cellular communication, however, only few single molecule methods are currently available to study how monovalent and multivalent GAG·protein bonds respond to directed mechanical forces. Here, we have devised such a method, by combining purpose-designed surfaces that afford immobilization of GAGs and receptors at controlled nanoscale organizations with single molecule force spectroscopy (SMFS). We apply the method to study the interaction of the GAG polymer hyaluronan (HA) with CD44, its receptor in vascular endothelium. Individual bonds between HA and CD44 are remarkably resistant to rupture under force in comparison to their low binding affinity. Multiple bonds along a single HA chain rupture sequentially and independently under load. We also demonstrate how strong non-covalent bonds, which are versatile for controlled protein and GAG immobilization, can be effectively used as molecular anchors in SMFS. We thus establish a versatile method for analyzing the nanomechanics of GAG·protein interactions at the level of single GAG chains, which provides new molecular-level insight into the role of mechanical forces in the assembly and function of GAG-rich extracellular matrices.
Collapse
Affiliation(s)
- Fouzia Bano
- CIC biomaGUNE, Paseo Miramon 182, 20009 Donostia-San Sebastian, Spain
| | - Suneale Banerji
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX39DS, UK
| | - Mark Howarth
- Department of Biochemistry, University of Oxford, Oxford, OX13QU, UK
| | - David G Jackson
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX39DS, UK
| | - Ralf P Richter
- CIC biomaGUNE, Paseo Miramon 182, 20009 Donostia-San Sebastian, Spain.,Université Grenoble Alpes - CNRS, Laboratoire Interdisciplinaire de Physique (LIPhy), BP 87, 38402 Saint Martin d'Hères, France.,University of Leeds, School of Biomedical Sciences and School of Physics and Astronomy, Leeds, LS2 9JT, UK
| |
Collapse
|
13
|
Arya G. Models for recovering the energy landscape of conformational transitions from single-molecule pulling experiments. MOLECULAR SIMULATION 2016. [DOI: 10.1080/08927022.2015.1123257] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
14
|
Dumitru AC, Herruzo ET, Rausell E, Ceña V, Garcia R. Unbinding forces and energies between a siRNA molecule and a dendrimer measured by force spectroscopy. NANOSCALE 2015; 7:20267-20276. [PMID: 26580848 DOI: 10.1039/c5nr04906g] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We have measured the intermolecular forces between small interference RNA (siRNA) and polyamidoamine dendrimers at the single molecular level. A single molecule force spectroscopy approach has been developed to measure the unbinding forces and energies between a siRNA molecule and polyamidoamine dendrimers deposited on a mica surface in a buffer solution. We report three types of unbinding events which are characterized by forces and free unbinding energies, respectively, of 28 pN, 0.709 eV; 38 pN, 0.722 eV; and 50 pN, 0.724 eV. These events reflect different possible electrostatic interactions between the positive charges of one or two dendrimers and the negatively charged phosphate groups of a single siRNA. We have evidence of a high binding affinity of siRNA towards polyamidoamine dendrimers that leads to a 45% probability of measuring specific unbinding events.
Collapse
Affiliation(s)
- Andra C Dumitru
- Instituto de Ciencia de Materiales de Madrid, CSIC, c/Sor Juana Ines de la Cruz 3, 28049 Madrid, Spain.
| | | | | | | | | |
Collapse
|
15
|
Das P, Reches M. Review insights into the interactions of amino acids and peptides with inorganic materials using single molecule force spectroscopy. Biopolymers 2015; 104:480-94. [DOI: 10.1002/bip.22655] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 03/18/2015] [Accepted: 03/30/2015] [Indexed: 01/11/2023]
Affiliation(s)
- Priyadip Das
- Institute of Chemistry, The Hebrew University of Jerusalem; 91904 Jerusalem Israel
- The Center for Nanoscience and Nanotechnology; The Hebrew University of Jerusalem; 91904 Jerusalem Israel
| | | |
Collapse
|
16
|
Gogia S, Lo CY, Neelamegham S. Detection of Plasma Protease Activity Using Microsphere-Cytometry Assays with E. coli Derived Substrates: VWF Proteolysis by ADAMTS13. PLoS One 2015; 10:e0126556. [PMID: 25992814 PMCID: PMC4436310 DOI: 10.1371/journal.pone.0126556] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 04/03/2015] [Indexed: 11/19/2022] Open
Abstract
Protease levels in human blood are often prognostic indicators of inflammatory, thrombotic or oncogenic disorders. The measurement of such enzyme activities in substrate-based assays is complicated due to the low prevalence of these enzymes and steric hindrance of the substrates by the more abundant blood proteins. To address these limitations, we developed a molecular construct that is suitable for microsphere-cytometer based assays in the milieu of human blood plasma. In this proof of principle study, we demonstrate the utility of this substrate to measure metalloprotease ADAMTS13 activity. The substrate, expressed in E. coli as a fusion protein, contains the partial A2-domain of von Willebrand factor (VWF amino acids 1594-1670) that is mutated to include a single primary amine at the N-terminus and free cysteines at the C-terminus. N-terminus fluorescence conjugation was possible using NHS (N-hydroxysuccinimide) chemistry. Maleimide-PEG(Polyethylene glycol)n-biotin coupling at the C-terminus allowed biotinylation with variable PEG spacer lengths. Once bound to streptavidin-bearing microspheres, the substrate fluorescence signal decreased in proportion with ADAMTS13 concentration. Whereas recombinant ADAMTS13 activity could be quantified using substrates with all PEG repeat-lengths, only the construct with the longer 77 PEG-unit could quantify proteolysis in blood plasma. Using this longer substrate, plasma ADAMTS13 down to 5% of normal levels could be detected within 30 min. Such measurements could also be readily performed under conditions resembling hyperbilirubinemia. Enzyme catalytic activity was tuned by varying buffer calcium, with lower divalent ion concentrations enhancing cleavage. Overall, the study highlights the substrate design features important for the creation of efficient proteolysis assays in the setting of human plasma. In particular, it emphasizes the need to introduce PEG spacers in plasma-based experiments, a design attribute commonly ignored in immobilized peptide-substrate assays.
Collapse
Affiliation(s)
- Shobhit Gogia
- Department of Chemical and Biological Engineering and NY State Center for Excellence in Bioinformatics and Life Sciences, State University of New York, Buffalo, New York, United States of America
| | - Chi Y. Lo
- Department of Chemical and Biological Engineering and NY State Center for Excellence in Bioinformatics and Life Sciences, State University of New York, Buffalo, New York, United States of America
| | - Sriram Neelamegham
- Department of Chemical and Biological Engineering and NY State Center for Excellence in Bioinformatics and Life Sciences, State University of New York, Buffalo, New York, United States of America
- * E-mail:
| |
Collapse
|
17
|
Bacharouche J, Degardin M, Jierry L, Carteret C, Lavalle P, Hemmerlé J, Senger B, Auzély-Velty R, Boulmedais F, Boturyn D, Coche-Guérente L, Schaaf P, Francius G. Multivalency: influence of the residence time and the retraction rate on rupture forces measured by AFM. J Mater Chem B 2015; 3:1801-1812. [DOI: 10.1039/c4tb01261e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Molecular orientation and flexibility of β-CD modulate the contact time and the multivalence effects of specific host–guest interactions.
Collapse
|
18
|
Wang C, Yadavalli VK. Spatial recognition and mapping of proteins using DNA aptamers. NANOTECHNOLOGY 2014; 25:455101. [PMID: 25338629 DOI: 10.1088/0957-4484/25/45/455101] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Atomic force microscopy-based adhesion force measurements have emerged as a powerful tool for the biophysical analyses of biological systems. Such measurements can now be extended to detection and mapping of biomolecules on surfaces via integrated imaging and force spectroscopy techniques. Critical to these experiments is the choice of the biomolecular recognition probe. In this study, we demonstrate how oligonucleotide aptamers can be used as versatile probes to simultaneously image and spatially locate targets on surfaces. We focus on two structurally distinct proteins relevant to the clotting cascade - human α-thrombin and vascular endothelial growth factor. Via AFM-recognition mapping using specific DNA aptamers on a commercially available instrument, we show a clear consistency between height and force measurements obtained simultaneously. Importantly, we are able to observe changes in binding due to changes in the external microenvironment, which demonstrate the ability to study fluctuating biological systems in real time. The aptamer specificity and the ability to distinguish their targets are shown through positive and negative controls. It is therefore possible to generate high resolution maps to spatially and temporally identify proteins at the molecular level on complex surfaces.
Collapse
|
19
|
Rakshit S, Sivasankar S. Biomechanics of cell adhesion: how force regulates the lifetime of adhesive bonds at the single molecule level. Phys Chem Chem Phys 2014; 16:2211-23. [PMID: 24419646 DOI: 10.1039/c3cp53963f] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cell adhesion proteins play critical roles in positioning cells during development, segregating cells into distinct tissue compartments and in maintaining tissue integrity. The principle function of these proteins is to bind cells together and resist mechanical force. Adhesive proteins also enable migrating cells to adhere and roll on surfaces even in the presence of shear forces exerted by fluid flow. Recently, several experimental and theoretical studies have provided quantitative insights into the physical mechanisms by which adhesion proteins modulate their unbinding kinetics in response to tensile force. This perspective reviews these biophysical investigations. We focus on single molecule studies of cadherins, selectins, integrins, the von Willebrand factor and FimH adhesion proteins; the effect of mechanical force on the lifetime of these interactions has been extensively characterized. We review both theoretical models and experimental investigations and discuss future directions in this exciting area of research.
Collapse
Affiliation(s)
- Sabyasachi Rakshit
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA.
| | | |
Collapse
|
20
|
Bizzarri AR, Cannistraro S. Antigen-antibody biorecognition events as discriminated by noise analysis of force spectroscopy curves. NANOTECHNOLOGY 2014; 25:335102. [PMID: 25073811 DOI: 10.1088/0957-4484/25/33/335102] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Atomic force spectroscopy is able to extract kinetic and thermodynamic parameters of biomolecular complexes provided that the registered unbinding force curves could be reliably attributed to the rupture of the specific complex interactions. To this aim, a commonly used strategy is based on the analysis of the stretching features of polymeric linkers which are suitably introduced in the biomolecule-substrate immobilization procedure. Alternatively, we present a method to select force curves corresponding to specific biorecognition events, which relies on a careful analysis of the force fluctuations of the biomolecule-functionalized cantilever tip during its approach to the partner molecules immobilized on a substrate. In the low frequency region, a characteristic 1/f (α) noise with α equal to one (flickering noise) is found to replace white noise in the cantilever fluctuation power spectrum when, and only when, a specific biorecognition process between the partners occurs. The method, which has been validated on a well-characterized antigen-antibody complex, represents a fast, yet reliable alternative to the use of linkers which may involve additional surface chemistry and reproducibility concerns.
Collapse
Affiliation(s)
- Anna Rita Bizzarri
- Biophysics and Nanoscience Centre, DEB, Università della Tuscia, Largo dell'Università, I-01100 Viterbo, Italy
| | | |
Collapse
|
21
|
Makky A, Viel P, Chen SWW, Berthelot T, Pellequer JL, Polesel-Maris J. Piezoelectric tuning fork probe for atomic force microscopy imaging and specific recognition force spectroscopy of an enzyme and its ligand. J Mol Recognit 2014; 26:521-31. [PMID: 24089359 DOI: 10.1002/jmr.2294] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 06/13/2013] [Accepted: 06/17/2013] [Indexed: 11/12/2022]
Abstract
Piezoelectric quartz tuning fork has drawn the attention of many researchers for the development of new atomic force microscopy (AFM) self-sensing probes. However, only few works have been done for soft biological materials imaging in air or aqueous conditions. The aim of this work was to demonstrate the efficiency of the AFM tuning fork probe to perform high-resolution imaging of proteins and to study the specific interaction between a ligand and its receptor in aqueous media. Thus, a new kind of self-sensing AFM sensor was introduced to realize imaging and biochemical specific recognition spectroscopy of glucose oxidase enzyme using a new chemical functionalization procedure of the metallic tips based on the electrochemical reduction of diazonium salt. This scanning probe as well as the functionalization strategy proved to be efficient respectively for the topography and force spectroscopy of soft biological materials in buffer conditions.
Collapse
Affiliation(s)
- Ali Makky
- CEA, IRAMIS, Service de Physique et Chimie des Surfaces et Interfaces, Gif-sur-Yvette, France
| | | | | | | | | | | |
Collapse
|
22
|
Pussak D, Ponader D, Mosca S, Pompe T, Hartmann L, Schmidt S. Specific adhesion of carbohydrate hydrogel particles in competition with multivalent inhibitors evaluated by AFM. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:6142-6150. [PMID: 24806833 DOI: 10.1021/la5010006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Synthetic glycooligomers have emerged as valuable analogues for multivalent glycan structures in nature. These multivalent carbohydrates bind to specific receptors and play a key role in biological processes. In this work, we investigate the specific interaction between mannose ligand presenting soft colloidal probes (SCPs) attached to an atomic force microscope (AFM) cantilever and a Concanavalin A (ConA) receptor surface in the presence of competing glycooligomer ligands. We studied the SCP-ConA adhesion energy via the JKR approach and AFM pull-off experiments in combination with optical microscopy allowing for simultaneous determination of the contact area between SCP and ConA surface. We varied the contact time, loading rate and loading force and measured the resulting mannose/ConA interaction. The average adhesion energy per mannose ligand on the probe was 5 kJ/mol, suggesting that a fraction of mannose ligands presented on the SCP bound to the receptor surface. Adhesion measurements via competitive binding of the SCP in the presence of multivalent glycooligomer ligands did not indicate an influence of their multivalency on the glycooligomer displacement from the ConA surface. The absence of this "multivalency effect" indicates that glycooligomers and ConA do not associate via chelate complexes and shows that steric shielding by the glycooligomers does not slow their displacement upon competitive binding of a ligand presenting surface. These results highlight the high reversibility of carbohydrate-surface interactions, which could be an essential feature of recognition processes on the cell surface.
Collapse
Affiliation(s)
- Daniel Pussak
- Max-Planck-Institut für Kolloid- und Grenzflächenforschung, Wissenschaftspark Potsdam-Golm, Am Mühlenberg 1 OT Golm, 14426 Potsdam, Germany
| | | | | | | | | | | |
Collapse
|
23
|
Näreoja T, Ebner A, Gruber HJ, Taskinen B, Kienberger F, Hänninen PE, Hytönen VP, Hinterdorfer P, Härmä H. Kinetics of bioconjugate nanoparticle label binding in a sandwich-type immunoassay. Anal Bioanal Chem 2013; 406:493-503. [PMID: 24264621 DOI: 10.1007/s00216-013-7474-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 10/16/2013] [Accepted: 10/30/2013] [Indexed: 11/29/2022]
Abstract
Nanoparticle labels have enhanced the performance of diagnostic, screening, and other measurement applications and hold further promise for more sensitive, precise, and cost-effective assay technologies. Nevertheless, a clear view of the biomolecular interactions on the molecular level is missing. Controlling the ratio of molecular recognition over undesired nonspecific adhesion is the key to improve biosensing with nanoparticles. To improve this ratio with an aim to disallow nonspecific binding, a more detailed perspective into the kinetic differences between the cases is needed. We present the application of two novel methods to determine complex binding kinetics of bioconjugate nanoparticles, interferometry, and force spectroscopy. Force spectroscopy is an atomic force microscopy technique and optical interferometry is a direct method to monitor reaction kinetics in second-hour timescale, both having steadily increasing importance in nanomedicine. The combination is perfectly suited for this purpose, due to the high sensitivity to detect binding events and the ability to investigate biological samples under physiological conditions. We have attached a single biofunctionalized nanoparticle to the outer tip apex and studied the binding behavior of the nanoparticle in a sandwich-type immunoassay using dynamic force spectroscopy in millisecond timescale. Utilization of the two novel methods allowed characterization of binding kinetics in a time range spanning from 50 ms to 4 h. These experiments allowed detection and demonstration of differences between specific and nonspecific binding. Most importantly, nonspecific binding of a nanoparticle was reduced at contact times below 100 ms with the solid-phase surface.
Collapse
Affiliation(s)
- Tuomas Näreoja
- Laboratory of Biophysics, Institute of Biomedicine and Medicity Research Laboratories, University of Turku, Tykistökatu 6A, 20520, Turku, Finland,
| | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Chung JW, Shin D, Kwak JM, Seog J. Direct force measurement of single DNA-peptide interactions using atomic force microscopy. J Mol Recognit 2013; 26:268-75. [PMID: 23595808 DOI: 10.1002/jmr.2269] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 01/24/2013] [Accepted: 02/01/2013] [Indexed: 11/10/2022]
Abstract
The selective interactions between DNA and miniature (39 residues) engineered peptide were directly measured at the single-molecule level by using atomic force microscopy. This peptide (p007) contains an α-helical recognition site similar to leucine zipper GCN4 and specifically recognizes the ATGAC sequence in the DNA with nanomolar affinity. The average rupture force was 42.1 pN, which is similar to the unbinding forces of the digoxigenin-antidigoxigenin complex, one of the strongest interactions in biological systems. The single linear fit of the rupture forces versus the logarithm of pulling rates showed a single energy barrier with a transition state located at 0.74 nm from the bound state. The smaller koff compared with that of other similar systems was presumably due to the increased stability of the helical structure by putative folding residues in p007. This strong sequence-specific DNA-peptide interaction has a potential to be utilized to prepare well-defined mechanically stable DNA-protein hybrid nanostructures.
Collapse
Affiliation(s)
- Ji W Chung
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | | | | | | |
Collapse
|
25
|
Yu K, Creagh AL, Haynes CA, Kizhakkedathu JN. Lectin Interactions on Surface-Grafted Glycostructures: Influence of the Spatial Distribution of Carbohydrates on the Binding Kinetics and Rupture Forces. Anal Chem 2013; 85:7786-93. [DOI: 10.1021/ac401306b] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
| | - A. Louise Creagh
- Michael Smith Laboratories and
Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, British Columbia V6T
1Z4, Canada
| | - Charles A. Haynes
- Michael Smith Laboratories and
Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, British Columbia V6T
1Z4, Canada
| | | |
Collapse
|
26
|
Tong Z, Mikheikin A, Krasnoslobodtsev A, Lv Z, Lyubchenko YL. Novel polymer linkers for single molecule AFM force spectroscopy. Methods 2013; 60:161-8. [PMID: 23624104 DOI: 10.1016/j.ymeth.2013.02.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 02/20/2013] [Accepted: 02/27/2013] [Indexed: 11/30/2022] Open
Abstract
Flexible polymer linkers play an important role in various imaging and probing techniques that require surface immobilization, including atomic force microscopy (AFM). In AFM force spectroscopy, polymer linkers are necessary for the covalent attachment of molecules of interest to the AFM tip and the surface. The polymer linkers tether the molecules and provide their proper orientation in probing experiments. Additionally, the linkers separate specific interactions from nonspecific short-range adhesion and serve as a reference point for the quantitative analysis of single molecule probing events. In this report, we present our results on the synthesis and testing of a novel polymer linker and the identification of a number of potential applications for its use in AFM force spectroscopy experiments. The synthesis of the linker is based on the well-developed phosphoramidate (PA) chemistry that allows the routine synthesis of linkers with predetermined lengths and PA composition. These linkers are homogeneous in length and can be terminated with various functional groups. PA linkers with different functional groups were synthesized and tested in experimental systems utilizing different immobilization chemistries. We probed interactions between complementary DNA oligonucleotides; DNA and protein complexes formed by the site-specific binding protein SfiI; and interactions between amyloid peptide (Aβ42). The results of the AFM force spectroscopy experiments validated the feasibility of the proposed approach for the linker design and synthesis. Furthermore, the properties of the tether (length, functional groups) can be adjusted to meet the specific requirements for different force spectroscopy experiments and system characteristics, suggesting that it could be used for a large number of various applications.
Collapse
Affiliation(s)
- Zenghan Tong
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha, NE 68198, USA
| | | | | | | | | |
Collapse
|
27
|
|
28
|
Eichmann SL, Meric G, Swavola JC, Bevan MA. Diffusing colloidal probes of protein-carbohydrate interactions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:2299-2310. [PMID: 23330828 DOI: 10.1021/la304355t] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present diffusing colloidal probe measurements of weak, multivalent, specific protein-polysaccharide interactions mediated by a competing monosaccharide. Specifically, we used integrated evanescent wave and video microscopy methods to monitor the three-dimensional Brownian excursions of conconavilin A (ConA) decorated colloids interacting with dextran-functionalized surfaces in the presence of glucose. Particle trajectories were interpreted as binding lifetime histograms, binding isotherms, and potentials of mean force. Binding lifetimes and isotherms showed clear trends of decreasing ConA-dextran-specific binding with increasing glucose concentration, consistent with expectations. Net potentials were accurately captured by superposition of a short-range, glucose-independent ConA-dextran repulsion and a longer-range, glucose-dependent dextran bridging attraction modeled as a harmonic potential. For glucose concentrations greater than 100 mM, the net ConA-dextran potential was found to have only a nonspecific repulsion, similar to that of bovine serum albumin (BSA) decorated colloids over dextran determined in control experiments. Our results demonstrate the first use of optical microscopy methods to quantify the connections between potentials of mean force and the binding behavior of ConA-decorated colloids on dextran-functionalized surfaces.
Collapse
Affiliation(s)
- Shannon L Eichmann
- Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | | | | | | |
Collapse
|
29
|
Hentschel C, Wagner H, Smiatek J, Heuer A, Fuchs H, Zhang X, Studer A, Chi L. AFM-based force spectroscopy on polystyrene brushes: effect of brush thickness on protein adsorption. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:1850-1856. [PMID: 23343216 DOI: 10.1021/la302212h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Herein we present a study on nonspecific binding of proteins at highly dense packed hydrophobic polystyrene brushes. In this context, an atomic force microscopy tip was functionalized with concanavalin A to perform single-molecule force spectroscopy measurements on polystyrene brushes with thicknesses of 10 and 60 nm, respectively. Polystyrene brushes with thickness of 10 nm show an almost two times stronger protein adsorption than brushes with a thickness of 60 nm: 72 pN for the thinner and 38 pN for the thicker layer, which is in qualitative agreement with protein adsorption studies conducted macroscopically by fluorescence microscopy.
Collapse
Affiliation(s)
- Carsten Hentschel
- Physikalisches Institut, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
| | | | | | | | | | | | | | | |
Collapse
|
30
|
Bizzarri AR, Santini S, Coppari E, Bucciantini M, Di Agostino S, Yamada T, Beattie CW, Cannistraro S. Interaction of an anticancer peptide fragment of azurin with p53 and its isolated domains studied by atomic force spectroscopy. Int J Nanomedicine 2011; 6:3011-9. [PMID: 22162658 PMCID: PMC3230568 DOI: 10.2147/ijn.s26155] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
p28 is a 28-amino acid peptide fragment of the cupredoxin azurin derived from Pseudomonas aeruginosa that preferentially penetrates cancerous cells and arrests their proliferation in vitro and in vivo. Its antitumor activity reportedly arises from post-translational stabilization of the tumor suppressor p53 normally downregulated by the binding of several ubiquitin ligases. This would require p28 to specifically bind to p53 to inhibit specific ligases from initiating proteosome-mediated degradation. In this study, atomic force spectroscopy, a nanotechnological approach, was used to investigate the interaction of p28 with full-length p53 and its isolated domains at the single molecule level. Analysis of the unbinding forces and the dissociation rate constant suggest that p28 forms a stable complex with the DNA-binding domain of p53, inhibiting the binding of ubiquitin ligases other than Mdm2 to reduce proteasomal degradation of p53.
Collapse
Affiliation(s)
- Anna Rita Bizzarri
- Biophysics and Nanoscience Centre, CNISM, Facoltà di Scienze, Università della Tuscia, Viterbo, Italy.
| | | | | | | | | | | | | | | |
Collapse
|
31
|
Ditzler LR, Sen A, Gannon MJ, Kohen A, Tivanski AV. Self-assembled enzymatic monolayer directly bound to a gold surface: activity and molecular recognition force spectroscopy studies. J Am Chem Soc 2011; 133:13284-7. [PMID: 21809877 PMCID: PMC4343314 DOI: 10.1021/ja205409v] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Escherichia coli dihydrofolate reductase (ecDHFR) has one surface cysteine, C152, located opposite and distal to the active site. Here, we show that the enzyme spontaneously assembles on an ultraflat gold surface as a homogeneous, covalently bound monolayer. Surprisingly, the activity of the gold-immobilized ecDHFR as measured by radiographic analysis was found to be similar to that of the free enzyme in solution. Molecular recognition force spectroscopy was used to study the dissociation forces involved in the rupture of AFM probe-tethered methotrexate (MTX, a tight-binding inhibitor of DHFR) from the gold-immobilized enzyme. Treatment of the ecDHFR monolayer with free MTX diminished the interaction of the functionalized tip with the surface, suggesting that the interaction was indeed active-site specific. These findings demonstrate the viability of a simple and direct enzymatic surface-functionalization without the use of spacers, thus, opening the door to further applications in the area of biomacromolecular force spectroscopy.
Collapse
Affiliation(s)
| | | | - Michael J. Gannon
- The Department of Chemistry, The University of Iowa, Iowa City, IA 52245
| | - Amnon Kohen
- The Department of Chemistry, The University of Iowa, Iowa City, IA 52245
| | - Alexei V. Tivanski
- The Department of Chemistry, The University of Iowa, Iowa City, IA 52245
| |
Collapse
|
32
|
Tsapikouni T, Missirlis YF. P-selectin/ligand unbinding force measured with atomic force microscopy: comparison of two chemical protocols for the tethering of single molecules. J Mol Recognit 2011; 24:847-53. [PMID: 21812059 DOI: 10.1002/jmr.1127] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Leukocytes, as an indispensable arm of the immune system, need to be recruited from the flowing blood and transferred to the sites of infection. Their extravasation is feasible due to their ability to tether and roll over the activated endothelium, which is much dependent on the association of their selectin molecules with ligands on the activated endothelial cells. In view of the importance of this interaction for the physiological immune functions as well as for autoimmune diseases, specifying the affinity of selectins to their ligands at the single molecule level appears a challenging task to gain insight into the mechanisms that control leukocyte-endothelial avidity. To this end we functionalized substrates with P-selectin and cantilever probes with its major ligand, the P-selectin glycoprotein ligand-1, and used atomic force microscopy to measure their unbinding force. Two different chemical protocols were used for the tethering of the molecules on the substrates, one based on a homobifunctional poly(ethylene glycol) linker and the other on the use of antibody-specific binding. The unbinding forces measured with the two methods were 312 ± 149 and 230 ± 57 pN, respectively. Measurements on activated endothelials, declaratory of single molecule interactions, gave comparable results.
Collapse
Affiliation(s)
- Theodora Tsapikouni
- Laboratory of Biomechanics and Biomedical Engineering, Mechanical Engineering and Aeronautics Department, University of Patras, Patras 26504, Greece.
| | | |
Collapse
|
33
|
Wildling L, Unterauer B, Zhu R, Rupprecht A, Haselgrübler T, Rankl C, Ebner A, Vater D, Pollheimer P, Pohl EE, Hinterdorfer P, Gruber HJ. Linking of sensor molecules with amino groups to amino-functionalized AFM tips. Bioconjug Chem 2011; 22:1239-48. [PMID: 21542606 PMCID: PMC3115690 DOI: 10.1021/bc200099t] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
![]()
The measuring tip of an atomic force microscope (AFM) can be upgraded to a specific biosensor by attaching one or a few biomolecules to the apex of the tip. The biofunctionalized tip is then used to map cognate target molecules on a sample surface or to study biophysical parameters of interaction with the target molecules. The functionality of tip-bound sensor molecules is greatly enhanced if they are linked via a thin, flexible polymer chain. In a typical scheme of tip functionalization, reactive groups are first generated on the tip surface, a bifunctional cross-linker is then attached with one of its two reactive ends, and finally the probe molecule of interest is coupled to the free end of the cross-linker. Unfortunately, the most popular functional group generated on the tip surface is the amino group, while at the same time, the only useful coupling functions of many biomolecules (such as antibodies) are also NH2 groups. In the past, various tricks or detours were applied to minimize the undesired bivalent reaction of bifunctional linkers with adjacent NH2 groups on the tip surface. In the present study, an uncompromising solution to this problem was found with the help of a new cross-linker (“acetal-PEG-NHS”) which possesses one activated carboxyl group and one acetal-protected benzaldehyde function. The activated carboxyl ensures rapid unilateral attachment to the amino-functionalized tip, and only then is the terminal acetal group converted into the amino-reactive benzaldehyde function by mild treatment (1% citric acid, 1–10 min) which does not harm the AFM tip. As an exception, AFM tips with magnetic coating become demagnetized in 1% citric acid. This problem was solved by deprotecting the acetal group before coupling the PEG linker to the AFM tip. Bivalent binding of the corresponding linker (“aldehyde-PEG-NHS”) to adjacent NH2 groups on the tip was largely suppressed by high linker concentrations. In this way, magnetic AFM tips could be functionalized with an ethylene diamine derivative of ATP which showed specific interaction with mitochondrial uncoupling protein 1 (UCP1) that had been purified and reconstituted in a mica-supported planar lipid bilayer.
Collapse
Affiliation(s)
- Linda Wildling
- Institute of Biophysics, J. Kepler University, Altenberger Str. 69, A-4040 Linz, Austria
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Mori T, Asakura M, Okahata Y. Single-Molecule Force Spectroscopy for Studying Kinetics of Enzymatic Dextran Elongations. J Am Chem Soc 2011; 133:5701-3. [DOI: 10.1021/ja200094f] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
35
|
Bizzarri AR, Cannistraro S. Free energy evaluation of the p53-Mdm2 complex from unbinding work measured by dynamic force spectroscopy. Phys Chem Chem Phys 2011; 13:2738-43. [DOI: 10.1039/c0cp01474e] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
36
|
Madwar C, Kwan WC, Deng L, Ramström O, Schmidt R, Zou S, Cuccia LA. Perfluorophenyl azide immobilization chemistry for single molecule force spectroscopy of the concanavalin A/mannose interaction. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:16677-16680. [PMID: 20964389 DOI: 10.1021/la1036579] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The versatility of perfluorophenyl azide (PFPA) derivatives makes them useful for attaching a wide variety of biomolecules and polymers to surfaces. Herein, a single molecule force spectroscopy (SMFS) study of the concanavalin A/mannose interaction was carried out using PFPA immobilization chemistry. SMFS of the concanavalin A/mannose interaction yielded an average unbinding force of 70-80 pN for loading rates between 8000 and 40,000 pN/s for mannose surfaces on aminated glass, and an unbinding force of 57 ± 20 pN at 6960 pN/s for mannose surfaces on gold-coated glass. Dynamic force spectroscopy was used to determine the dissociation rate constant, k(off), for this interaction to be 0.16 s(-1).
Collapse
Affiliation(s)
- Carolin Madwar
- Department of Chemistry & Biochemistry, Concordia University, 7141 Sherbrooke Street West, Montréal, Québec, Canada H4B 1R6
| | | | | | | | | | | | | |
Collapse
|
37
|
Mayyas E, Bernardo M, Runyan L, Sohail A, Subba-Rao V, Pantea M, Fridman R, Hoffmann PM. Dissociation Kinetics of an Enzyme−Inhibitor System Using Single-Molecule Force Measurements. Biomacromolecules 2010; 11:3352-8. [DOI: 10.1021/bm100844x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Essa Mayyas
- Department of Physics and Astronomy, and Department of Pathology and Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201, United States
| | - Margarida Bernardo
- Department of Physics and Astronomy, and Department of Pathology and Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201, United States
| | - Lindsay Runyan
- Department of Physics and Astronomy, and Department of Pathology and Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201, United States
| | - Anjum Sohail
- Department of Physics and Astronomy, and Department of Pathology and Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201, United States
| | - Venkatesh Subba-Rao
- Department of Physics and Astronomy, and Department of Pathology and Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201, United States
| | - Mircea Pantea
- Department of Physics and Astronomy, and Department of Pathology and Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201, United States
| | - Rafael Fridman
- Department of Physics and Astronomy, and Department of Pathology and Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201, United States
| | - Peter M. Hoffmann
- Department of Physics and Astronomy, and Department of Pathology and Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201, United States
| |
Collapse
|
38
|
Maitra A, Arya G. Influence of pulling handles and device stiffness in single-molecule force spectroscopy. Phys Chem Chem Phys 2010; 13:1836-42. [PMID: 20938520 DOI: 10.1039/c0cp01528h] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In single-molecule force spectroscopy, individual molecules and complexes are often stretched by pulling devices via intervening molecular handles. Accurate interpretation of measurements from such experiments in terms of the underlying energy landscape, defined by activation barriers and intrinsic rates of transition, relies on our understanding, and proper theoretical treatment, of the effects of the pulling device and handle. Here, we present a framework based on Kramers' theory that elucidates the dependence of measured rupture forces and rates on the pulling device stiffness and attributes of the handle, contour length and persistence length. We also introduce a simple analytic model that improves prediction of activation barriers and intrinsic rates for all device stiffnesses and handle properties, thus allowing for a more reliable interpretation of experiments. Our analyses also suggests intuitive ways of displaying the measured force spectra for proper prognosis of device and handle effects and provides the range of device and handle attributes over which these effects can be neglected.
Collapse
Affiliation(s)
- Arijit Maitra
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0448, USA
| | | |
Collapse
|
39
|
Funari G, Domenici F, Nardinocchi L, Puca R, D'Orazi G, Bizzarri AR, Cannistraro S. Interaction of p53 with Mdm2 and azurin as studied by atomic force spectroscopy. J Mol Recognit 2010; 23:343-51. [PMID: 19941302 DOI: 10.1002/jmr.999] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Azurin, a bacterial protein, can be internalized in cancer cells and induce apoptosis. Such anticancer effect is coupled to the formation of a complex with the tumour-suppressor p53. The mechanism by which azurin stabilizes p53 and the binding sites of their complex are still under investigation. It is also known that the predominant mechanism for p53 down-regulation implies its association to Mdm2, the main ubiquitin ligase affecting its stability. However, the p53/Mdm2 interaction, occurring at the level of both their N-terminal domains, has been characterized so far by experiments involving only partial domains of these proteins. The relevance of the p53/Mdm2 complex as a possible target of the anticancer therapies requires a deeper study of this complex as made up of the two entire proteins. Moreover, the apparent antagonist action of azurin against Mdm2, with respect of p53 regulation, might suggest the possibility that azurin binds p53 at the same site of Mdm2, preventing in such a way p53 and Mdm2 from association and thus p53 from degradation. By following the interaction of the two entire proteins by atomic force spectroscopy, we have assessed the formation of a specific complex between p53 and Mdm2. We found for it a binding strength and a dissociation rate constant typical of dynamical protein-protein interactions and we observed that azurin, even if capable to bind p53, does not compete with Mdm2 for the same binding site on p53. The formation of the p53/Mdm2/azurin ternary complex might suggest an alternative anti-cancer mechanism adopted by azurin.
Collapse
Affiliation(s)
- Gloria Funari
- Biophysics and Nanoscience Centre, CNISM, Facoltà di Scienze, Università della Tuscia, Viterbo, Italy
| | | | | | | | | | | | | |
Collapse
|
40
|
Ray C, Guo S, Brown J, Li N, Akhremitchev BB. Kinetic parameters from detection probability in single molecule force spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:11951-11957. [PMID: 20496933 DOI: 10.1021/la101269q] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The detection probability of rupture events in AFM force spectroscopy measurements presents a viable alternative to standard methods for extracting kinetic parameters of dissociation. The detection probability has a maximum as a function of the probe velocity where (1) the probability to form a molecular bond is independent of the probe velocity and (2) the detection of rupture events is limited by noise and performed with a constant density of data points per distance of the probe displacement. This newly developed model indicates that the optimal detection velocity is independent of dissociation rate and depends on the distance to the barrier kinetic parameter. Therefore, the kinetic parameters of bond dissociation can be extracted from the dependence of detection probability on probe velocity and the detection threshold. This approach is sensitive to low rupture forces and therefore is complementary to the common most probable force data analysis approach. The developed approach is tested using rupture forces measured with specific bonds between biotin and streptavidin and with nonspecific bonds between linear alkanes in water. Results for the analysis of specific bonds rupture are consistent with the previous measurements, suggesting that rupture forces spanning a wide range of values originate from the same binding potential. Kinetic parameters obtained for linear alkanes are significantly different from previous measurements suggesting possible heterogeneity of the bound state.
Collapse
Affiliation(s)
- Chad Ray
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
| | | | | | | | | |
Collapse
|
41
|
Goossens K, Willaert R. Flocculation protein structure and cell–cell adhesion mechanism in Saccharomyces cerevisiae. Biotechnol Lett 2010; 32:1571-85. [DOI: 10.1007/s10529-010-0352-3] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Accepted: 07/02/2010] [Indexed: 01/08/2023]
|
42
|
Gromadzki D, Jigounov A, Štĕpánek P, Makuška R. Synthesis of thermally responsive cylindrical molecular brushes via a combination of nitroxide-mediated radical polymerization and “grafting onto” strategy. Eur Polym J 2010. [DOI: 10.1016/j.eurpolymj.2009.12.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
43
|
Lesoil C, Nonaka T, Sekiguchi H, Osada T, Miyata M, Afrin R, Ikai A. Molecular shape and binding force of Mycoplasma mobile’s leg protein Gli349 revealed by an AFM study. Biochem Biophys Res Commun 2010; 391:1312-7. [DOI: 10.1016/j.bbrc.2009.12.023] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2009] [Accepted: 12/07/2009] [Indexed: 11/29/2022]
|
44
|
Bizzarri AR, Cannistraro S. The application of atomic force spectroscopy to the study of biological complexes undergoing a biorecognition process. Chem Soc Rev 2010; 39:734-49. [DOI: 10.1039/b811426a] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
|
45
|
Bizzarri AR, Cannistraro S. Atomic Force Spectroscopy in Biological Complex Formation: Strategies and Perspectives. J Phys Chem B 2009; 113:16449-64. [DOI: 10.1021/jp902421r] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Anna Rita Bizzarri
- Biophysics and Nanoscience Centre, CNISM, Facoltà di Scienze, Università della Tuscia, Largo dell’Università, 01100 Viterbo, Italy
| | - Salvatore Cannistraro
- Biophysics and Nanoscience Centre, CNISM, Facoltà di Scienze, Università della Tuscia, Largo dell’Università, 01100 Viterbo, Italy
| |
Collapse
|
46
|
Tsapikouni TS, Missirlis YF. Measuring the force of single protein molecule detachment from surfaces with AFM. Colloids Surf B Biointerfaces 2009; 75:252-9. [PMID: 19783413 DOI: 10.1016/j.colsurfb.2009.08.041] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2009] [Revised: 08/04/2009] [Accepted: 08/27/2009] [Indexed: 10/20/2022]
Abstract
Atomic force microscopy (AFM) was used to measure the non-specific detachment force of single fibrinogen molecules from glass surfaces. The identification of single unbinding events was based on the characteristics of the parabolic curves, recorded during the stretching of protein molecules. Fibrinogen molecules were covalently bound to Si(3)N(4) AFM tips, previously modified with 3-aminopropyl-dimethyl-ethoxysilane, through a homobifunctional poly(ethylene glycol) linker bearing two hydroxysulfosuccinimide esters. The most probable detachment force was found to be 210 pN, when the tip was retracting with a velocity of 1400 nm/s, while the distribution of the detachment distances indicated that the fibrinogen chain can be elongated beyond the length of the physical conformation before detachment. The dependence of the most probable detachment force on the loading rate was examined and the dynamics of fibrinogen binding to the surface were found amenable to the simple expression of the Bell-Evans theory. The theory's expansion, however, by incorporating the concept of the rupture of parallel residue-surface bonds could only describe the detachment of fibrinogen for a small number of such bonds. Finally, the mathematical expression of the Worm-Like Chain model was used to fit the stretching curves before rupture and two interpretations are suggested for the description of the AFM curves with multiple detachment events.
Collapse
Affiliation(s)
- Theodora S Tsapikouni
- Laboratory of Biomechanics and Biomedical Engineering, Mechanical Engineering and Aeronautics Department, University of Patras, Patras 26504, Greece.
| | | |
Collapse
|
47
|
Functionalized self-assembled monolayers for measuring single molecule lectin carbohydrate interactions. Anal Chim Acta 2009; 649:1-7. [DOI: 10.1016/j.aca.2009.07.027] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Revised: 07/07/2009] [Accepted: 07/08/2009] [Indexed: 01/10/2023]
|
48
|
Guo S, Lad N, Ray C, Akhremitchev BB. Association kinetics from single molecule force spectroscopy measurements. Biophys J 2009; 96:3412-22. [PMID: 19383484 DOI: 10.1016/j.bpj.2009.01.031] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Revised: 12/29/2008] [Accepted: 01/22/2009] [Indexed: 01/12/2023] Open
Abstract
Single molecule force spectroscopy is often used to study the dissociation of single molecules by applying mechanical force to the intermolecular bond. These measurements provide the kinetic parameters of dissociation. We present what to our knowledge is a new atomic force microscopy-based approach to obtain the activation energy of the association reaction and approximate grafting density of reactive receptors using the dependence of the probability to form molecular bonds on probe velocity when one of the interacting molecules is tethered by a flexible polymeric linker to the atomic force microscopy probe. Possible errors in the activation energy measured with this approach are considered and resulting corrections are included in the data analysis. This new approach uses the same experimental setup as traditional force spectroscopy measurements that quantify dissociation kinetics. We apply the developed methodology to measure the activation energy of biotin-streptavidin association (including a contribution from the steric factor) and obtain a value of 8 +/- 1 kT. This value is consistent with the association rate measured previously in solution. Comparison with the solution-derived activation energy indicates that kinetics of biotin-streptavidin binding is mainly controlled by the reaction step.
Collapse
Affiliation(s)
- Senli Guo
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
| | | | | | | |
Collapse
|
49
|
Lienemann M, Paananen A, Boer H, de la Fuente JM, García I, Penadés S, Koivula A. Characterization of the wheat germ agglutinin binding to self-assembled monolayers of neoglycoconjugates by AFM and SPR. Glycobiology 2009; 19:633-43. [PMID: 19240268 DOI: 10.1093/glycob/cwp030] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Carbohydrate-protein interactions govern many crucial life processes involved in cell recognition events, but are often difficult to study because the interactions are weak, and multivalent exposure appears to be crucial for their biological function. We have used self-assembled monolayers (SAMs) of neoglycoconjugates as a model system to probe the specific interactions between the lectin wheat germ agglutinin (WGA) and monosaccharides by surface plasmon resonance (SPR) and atomic force microscopy (AFM) force measurements. SAMs presenting N-acetyl-D-glucosamine (GlcNAc) as a neoglycoconjugate were produced on gold surfaces, where the SAM formation was monitored using a quartz crystal microbalance (QCM) and shown to be a very rapid process. In the AFM force measurements WGA was covalently coupled to flexible polyethylene glycol (PEG) molecules at a probe surface using amine coupling. GlcNAc-specific binding events were detected with a WGA-modified probe on the GlcNAc-neoglycoconjugate SAM at bond rupture forces of 47 +/- 15 pN. Additionally, less frequent GlcNAc-specific unbinding events were detected at higher forces (120 +/- 20 pN) which are believed to originate from simultaneous detachment of multiple binding sites from the SAM surface. SPR measurements confirmed that WGA has higher affinity toward the immobilized GlcNAc-SAM than toward the soluble free monosaccharide. The binding constants obtained for soluble chitinoligosaccharides suggested up to three subsites within one carbohydrate-binding site of the WGA molecule and also provided further evidence of the multivalent binding character of the WGA dimer.
Collapse
|
50
|
Xiang M, Xu X, Liu F, Li N, Li KA. Gold Nanoparticle Based Plasmon Resonance Light-Scattering Method as a New Approach for Glycogen−Biomacromolecule Interactions. J Phys Chem B 2009; 113:2734-8. [DOI: 10.1021/jp8065822] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Minghui Xiang
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Xiao Xu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Feng Liu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Na Li
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Ke-An Li
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| |
Collapse
|