1
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Ni B, Kaplan DL, Buehler MJ. ForceGen: End-to-end de novo protein generation based on nonlinear mechanical unfolding responses using a language diffusion model. SCIENCE ADVANCES 2024; 10:eadl4000. [PMID: 38324676 PMCID: PMC10849601 DOI: 10.1126/sciadv.adl4000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 01/08/2024] [Indexed: 02/09/2024]
Abstract
Through evolution, nature has presented a set of remarkable protein materials, including elastins, silks, keratins and collagens with superior mechanical performances that play crucial roles in mechanobiology. However, going beyond natural designs to discover proteins that meet specified mechanical properties remains challenging. Here, we report a generative model that predicts protein designs to meet complex nonlinear mechanical property-design objectives. Our model leverages deep knowledge on protein sequences from a pretrained protein language model and maps mechanical unfolding responses to create proteins. Via full-atom molecular simulations for direct validation, we demonstrate that the designed proteins are de novo, and fulfill the targeted mechanical properties, including unfolding energy and mechanical strength, as well as the detailed unfolding force-separation curves. Our model offers rapid pathways to explore the enormous mechanobiological protein sequence space unconstrained by biological synthesis, using mechanical features as the target to enable the discovery of protein materials with superior mechanical properties.
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Affiliation(s)
- Bo Ni
- Laboratory for Atomistic and Molecular Mechanics (LAMM), Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139, USA
| | - David L. Kaplan
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA
| | - Markus J. Buehler
- Laboratory for Atomistic and Molecular Mechanics (LAMM), Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139, USA
- Center for Computational Science and Engineering, Schwarzman College of Computing, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139, USA
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2
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Truong HP, Saleh OA. Magnetic tweezers characterization of the entropic elasticity of intrinsically disordered proteins and peptoids. Methods Enzymol 2024; 694:209-236. [PMID: 38492952 DOI: 10.1016/bs.mie.2023.12.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2024]
Abstract
Understanding the conformational behavior of biopolymers is essential to unlocking knowledge of their biophysical mechanisms and functional roles. Single-molecule force spectroscopy can provide a unique perspective on this by exploiting entropic elasticity to uncover key biopolymer structural parameters. A particularly powerful approach involves the use of magnetic tweezers, which can easily generate lower stretching forces (0.1-20 pN). For forces at the low end of this range, the elastic response of biopolymers is sensitive to excluded volume effects, and they can be described by Pincus blob elasticity model that allow robust extraction of the Flory polymer scaling exponent. Here, we detail protocols for the use of magnetic tweezers for force-extension measurements of intrinsically disordered proteins and peptoids. We also discuss procedures for fitting low-force elastic curves to the predictions of polymer physics models to extract key conformational parameters.
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Affiliation(s)
- Hoang P Truong
- Materials Department, University of California, Santa Barbara, CA, United States
| | - Omar A Saleh
- Materials Department, University of California, Santa Barbara, CA, United States; Biomolecular Sciences and Engineering Program, University of California, Santa Barbara, CA, United States; Physics Department, University of California, Santa Barbara, CA, United States.
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3
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Sun H, Le S, Guo Z, Chen H. Exploring the free energy landscape of proteins using magnetic tweezers. Methods Enzymol 2024; 694:237-261. [PMID: 38492953 DOI: 10.1016/bs.mie.2023.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2024]
Abstract
Proteins fold to their native states by searching through the free energy landscapes. As single-domain proteins are the basic building block of multiple-domain proteins or protein complexes composed of subunits, the free energy landscapes of single-domain proteins are of critical importance to understand the folding and unfolding processes of proteins. To explore the free energy landscapes of proteins over large conformational space, the stability of native structure is perturbed by biochemical or mechanical means, and the conformational transition process is measured. In single molecular manipulation experiments, stretching force is applied to proteins, and the folding and unfolding transitions are recorded by the extension time course. Due to the broad force range and long-time stability of magnetic tweezers, the free energy landscape over large conformational space can be obtained. In this article, we describe the magnetic tweezers instrument design, protein construct design and preparation, fluid chamber preparation, common-used measuring protocols including force-ramp and force-jump measurements, and data analysis methods to construct the free energy landscape. Single-domain cold shock protein is introduced as an example to build its free energy landscape by magnetic tweezers measurements.
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Affiliation(s)
- Hao Sun
- Center of Biomedical Physics, Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, P.R. China
| | - Shimin Le
- Department of Physics, Research Institute for Biomimetics and Soft Matter, Fujian Provincial Key Lab for Soft Functional Materials Research, Xiamen University, Xiamen, P.R. China
| | - Zilong Guo
- Center of Biomedical Physics, Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, P.R. China.
| | - Hu Chen
- Center of Biomedical Physics, Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, P.R. China; Department of Physics, Research Institute for Biomimetics and Soft Matter, Fujian Provincial Key Lab for Soft Functional Materials Research, Xiamen University, Xiamen, P.R. China.
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4
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Chu J, Romero A, Taulbee J, Aran K. Development of Single Molecule Techniques for Sensing and Manipulation of CRISPR and Polymerase Enzymes. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2300328. [PMID: 37226388 PMCID: PMC10524706 DOI: 10.1002/smll.202300328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 03/20/2023] [Indexed: 05/26/2023]
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR) and polymerases are powerful enzymes and their diverse applications in genomics, proteomics, and transcriptomics have revolutionized the biotechnology industry today. CRISPR has been widely adopted for genomic editing applications and Polymerases can efficiently amplify genomic transcripts via polymerase chain reaction (PCR). Further investigations into these enzymes can reveal specific details about their mechanisms that greatly expand their use. Single-molecule techniques are an effective way to probe enzymatic mechanisms because they may resolve intermediary conformations and states with greater detail than ensemble or bulk biosensing techniques. This review discusses various techniques for sensing and manipulation of single biomolecules that can help facilitate and expedite these discoveries. Each platform is categorized as optical, mechanical, or electronic. The methods, operating principles, outputs, and utility of each technique are briefly introduced, followed by a discussion of their applications to monitor and control CRISPR and Polymerases at the single molecule level, and closing with a brief overview of their limitations and future prospects.
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Affiliation(s)
- Josephine Chu
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, CA, 91711, USA
| | - Andres Romero
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, CA, 91711, USA
| | - Jeffrey Taulbee
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, CA, 91711, USA
| | - Kiana Aran
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, CA, 91711, USA
- Cardea, San Diego, CA, 92121, USA
- University of California Berkeley, Berkeley, CA, 94720, USA
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5
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Kuznets-Speck B, Limmer DT. Inferring equilibrium transition rates from nonequilibrium protocols. Biophys J 2023; 122:1659-1664. [PMID: 36964656 PMCID: PMC10183322 DOI: 10.1016/j.bpj.2023.03.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 01/08/2023] [Accepted: 03/21/2023] [Indexed: 03/26/2023] Open
Abstract
We develop a theory for inferring equilibrium transition rates from trajectories driven by a time-dependent force using results from stochastic thermodynamics. Applying the Kawasaki relation to approximate the nonequilibrium distribution function in terms of the equilibrium distribution function and the excess dissipation, we formulate a nonequilibrium transition state theory to estimate the rate enhancement over the equilibrium rate due to the nonequilibrium protocol. We demonstrate the utility of our theory in examples of pulling of harmonically trapped particles in one and two dimensions, as well as a semiflexible polymer with a reactive linker in three dimensions. We expect our purely thermodynamic approach will find use in both molecular simulation and force spectroscopy experiments.
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Affiliation(s)
| | - David T Limmer
- Chemistry Department, University of California, Berkeley, Berkeley, California; Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California; Material Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California; Kavli Energy NanoSciences Institute, University of California, Berkeley, Berkeley, California.
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6
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Gokulu IS, Banta S. Biotechnology applications of proteins functionalized with DNA oligonucleotides. Trends Biotechnol 2023; 41:575-585. [PMID: 36115723 DOI: 10.1016/j.tibtech.2022.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/16/2022] [Accepted: 08/18/2022] [Indexed: 10/14/2022]
Abstract
The functionalization of proteins with DNA through the formation of covalent bonds enables a wide range of biotechnology advancements. For example, single-molecule analytical methods rely on bioconjugated DNA as elastic biolinkers for protein immobilization. Labeling proteins with DNA enables facile protein identification, as well as spatial and temporal organization and control of protein within DNA-protein networks. Bioconjugation reactions can target native, engineered, and non-canonical amino acids (NCAAs) within proteins. In addition, further protein engineering via the incorporation of peptide tags and self-labeling proteins can also be used for conjugation reactions. The selection of techniques will depend on application requirements such as yield, selectivity, conjugation position, potential for steric hindrance, cost, commercial availability, and potential impact on protein function.
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Affiliation(s)
- Ipek Simay Gokulu
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, New York, NY 10027, USA
| | - Scott Banta
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, New York, NY 10027, USA.
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7
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Collagen-like Motifs of SasG: A Novel Fold for Protein Mechanical Strength. J Mol Biol 2023; 435:167980. [PMID: 36708761 DOI: 10.1016/j.jmb.2023.167980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 01/11/2023] [Accepted: 01/19/2023] [Indexed: 01/26/2023]
Abstract
The Staphylococcus aureus surface protein G (SasG) is associated with host colonisation and biofilm formation. As colonisation occurs at the liquid-substrate interface bacteria are subject to a myriad of external forces and, presumably as a consequence, SasG displays extreme mechanical strength. This mechanical phenotype arises from the B-domain; a repetitive region composed of alternating E and G5 subdomains. These subdomains have an unusual structure comprising collagen-like regions capped by triple-stranded β-sheets. To identify the determinants of SasG mechanical strength, we characterised the mechanical phenotype and thermodynamic stability of 18 single substitution variants of a pseudo-wildtype protein. Visualising the mechanically-induced transition state at a residue-level by ϕ-value analysis reveals that the main force-bearing regions are the N- and C-terminal 'Mechanical Clamps' and their side-chain interactions. This is tailored by contacts at the pseudo-hydrophobic core interface. We also describe a novel mechanical motif - the collagen-like region and show that glycine to alanine substitutions, analogous to those found in Osteogenesis Imperfecta (brittle bone disease), result in a significantly reduced mechanical strength.
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8
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Gomes PSFC, Forrester M, Pace M, Gomes DEB, Bernardi RC. May the force be with you: The role of hyper-mechanostability of the bone sialoprotein binding protein during early stages of Staphylococci infections. Front Chem 2023; 11:1107427. [PMID: 36846849 PMCID: PMC9944720 DOI: 10.3389/fchem.2023.1107427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 01/25/2023] [Indexed: 02/10/2023] Open
Abstract
The bone sialoprotein-binding protein (Bbp) is a mechanoactive MSCRAMM protein expressed on the surface of Staphylococcus aureus that mediates adherence of the bacterium to fibrinogen-α (Fgα), a component of the bone and dentine extracellular matrix of the host cell. Mechanoactive proteins like Bbp have key roles in several physiological and pathological processes. Particularly, the Bbp: Fgα interaction is important in the formation of biofilms, an important virulence factor of pathogenic bacteria. Here, we investigated the mechanostability of the Bbp: Fgα complex using in silico single-molecule force spectroscopy (SMFS), in an approach that combines results from all-atom and coarse-grained steered molecular dynamics (SMD) simulations. Our results show that Bbp is the most mechanostable MSCRAMM investigated thus far, reaching rupture forces beyond the 2 nN range in typical experimental SMFS pulling rates. Our results show that high force-loads, which are common during initial stages of bacterial infection, stabilize the interconnection between the protein's amino acids, making the protein more "rigid". Our data offer new insights that are crucial on the development of novel anti-adhesion strategies.
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Affiliation(s)
- Priscila S. F. C. Gomes
- Department of Physics, College of Sciences and Mathematics, Auburn University, Auburn, AL, United States
| | - Meredith Forrester
- Department of Physics, College of Sciences and Mathematics, Auburn University, Auburn, AL, United States
| | - Margaret Pace
- Department of Physics, College of Sciences and Mathematics, Auburn University, Auburn, AL, United States
| | - Diego E. B. Gomes
- Department of Physics, College of Sciences and Mathematics, Auburn University, Auburn, AL, United States
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9
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Cao N, Cai W, Qian L, Nie Z, Mao C, Cui S. Emulating Titin by a Multidomain DNA Structure. ACS Macro Lett 2023; 12:59-64. [PMID: 36573670 DOI: 10.1021/acsmacrolett.2c00585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Titin, a giant protein containing multiple tandem domains, is essential in maintaining the superior mechanical performance of muscle. The consecutive and reversible unfolding and refolding of the domains are crucial for titin to serve as a modular spring. Since the discovery of the mechanical features of a single titin molecule, the exploration of biomimetic materials with titin-emulating modular structures has been an active field. However, it remains a challenge to prepare these modular polymers on a large scale due to the complex synthesis process. In this study, we propose modular DNA with multiple hairpins (MH-DNA) as the fundamental block for the bottom-up design of advanced materials. By analyzing the unfolding and refolding dynamics of modular hairpins by atomic force microscopy (AFM)-based single-molecule force spectroscopy (SMFS), we find that MH-DNA shows comparable stability to those of polyproteins like titin. The unique low hysteresis of modular hairpin makes it an ideal molecular spring with remarkable mechanical efficiency. On the basis of the well-established DNA synthesis techniques, we anticipate that MH-DNA can be used as a promising building block for advanced materials with a combination of superior structural stability, considerable extensibility, and high mechanical efficiency.
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Affiliation(s)
- Nanpu Cao
- College of Chemistry, Key Laboratory of Advanced Technologies of Materials (Ministry of Education), Southwest Jiaotong University, Chengdu 610031, China
| | - Wanhao Cai
- College of Chemistry, Key Laboratory of Advanced Technologies of Materials (Ministry of Education), Southwest Jiaotong University, Chengdu 610031, China
| | - Lu Qian
- College of Chemistry, Key Laboratory of Advanced Technologies of Materials (Ministry of Education), Southwest Jiaotong University, Chengdu 610031, China
| | - Zhou Nie
- State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Chengde Mao
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Shuxun Cui
- College of Chemistry, Key Laboratory of Advanced Technologies of Materials (Ministry of Education), Southwest Jiaotong University, Chengdu 610031, China
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10
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Slawinski M, Kaeek M, Rajmiel Y, Khoury LR. Acetic Acid Enables Precise Tailoring of the Mechanical Behavior of Protein-Based Hydrogels. NANO LETTERS 2022; 22:6942-6950. [PMID: 36018622 PMCID: PMC9479135 DOI: 10.1021/acs.nanolett.2c01558] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 08/18/2022] [Indexed: 06/15/2023]
Abstract
Engineering viscoelastic and biocompatible materials with tailored mechanical and microstructure properties capable of mimicking the biological stiffness (<17 kPa) or serving as bioimplants will bring protein-based hydrogels to the forefront in the biomaterials field. Here, we introduce a method that uses different concentrations of acetic acid (AA) to control the covalent tyrosine-tyrosine cross-linking interactions at the nanoscale level during protein-based hydrogel synthesis and manipulates their mechanical and microstructure properties without affecting protein concentration and (un)folding nanomechanics. We demonstrated this approach by adding AA as a precursor to the preparation buffer of a photoactivated protein-based hydrogel mixture. This strategy allowed us to synthesize hydrogels made from bovine serum albumin (BSA) and eight repeats protein L structure, with a fine-tailored wide range of stiffness (2-35 kPa). Together with protein engineering technologies, this method will open new routes in developing and investigating tunable protein-based hydrogels and extend their application toward new horizons.
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Affiliation(s)
- Marina Slawinski
- Department
of Physics, University of Wisconsin—Milwaukee, 3135 N. Maryland Ave, Milwaukee, Wisconsin 53211, United States
| | - Maria Kaeek
- Department
of Materials Science and Engineering, Technion
Israel Institute of Technology, Haifa 32000, Israel
| | - Yair Rajmiel
- Department
of Materials Science and Engineering, Technion
Israel Institute of Technology, Haifa 32000, Israel
| | - Luai R. Khoury
- Department
of Materials Science and Engineering, Technion
Israel Institute of Technology, Haifa 32000, Israel
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11
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Harris NJ, Pellowe GA, Blackholly LR, Gulaidi-Breen S, Findlay HE, Booth PJ. Methods to study folding of alpha-helical membrane proteins in lipids. Open Biol 2022; 12:220054. [PMID: 35855589 PMCID: PMC9297032 DOI: 10.1098/rsob.220054] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
How alpha-helical membrane proteins fold correctly in the highly hydrophobic membrane interior is not well understood. Their folding is known to be highly influenced by the lipids within the surrounding bilayer, but the majority of folding studies have focused on detergent-solubilized protein rather than protein in a lipid environment. There are different ways to study folding in lipid bilayers, and each method has its own advantages and disadvantages. This review will discuss folding methods which can be used to study alpha-helical membrane proteins in bicelles, liposomes, nanodiscs or native membranes. These folding methods include in vitro folding methods in liposomes such as denaturant unfolding studies, and single-molecule force spectroscopy studies in bicelles, liposomes and native membranes. This review will also discuss recent advances in co-translational folding studies, which use cell-free expression with liposomes or nanodiscs or are performed in vivo with native membranes.
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Affiliation(s)
- Nicola J. Harris
- Department of Chemistry, King's College London, Britannia House, 7 Trinity Street, London, SE1 1DB, UK
| | - Grant A. Pellowe
- Department of Chemistry, King's College London, Britannia House, 7 Trinity Street, London, SE1 1DB, UK
| | - Laura R. Blackholly
- Department of Chemistry, King's College London, Britannia House, 7 Trinity Street, London, SE1 1DB, UK
| | | | - Heather E. Findlay
- Department of Chemistry, King's College London, Britannia House, 7 Trinity Street, London, SE1 1DB, UK,The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Paula J. Booth
- Department of Chemistry, King's College London, Britannia House, 7 Trinity Street, London, SE1 1DB, UK,The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
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12
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Veselov M, Uporov IV, Efremova MV, Le-Deygen IM, Prusov AN, Shchetinin IV, Savchenko AG, Golovin YI, Kabanov AV, Klyachko NL. Modulation of α-Chymotrypsin Conjugated to Magnetic Nanoparticles by the Non-Heating Low-Frequency Magnetic Field: Molecular Dynamics, Reaction Kinetics, and Spectroscopy Analysis. ACS OMEGA 2022; 7:20644-20655. [PMID: 35755395 PMCID: PMC9219078 DOI: 10.1021/acsomega.2c00704] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 05/25/2022] [Indexed: 06/15/2023]
Abstract
Enzymes conjugated to magnetic nanoparticles (MNPs) undergo changes in the catalytic activity of the non-heating low-frequency magnetic field (LFMF). We apply in silico simulations by molecular dynamics (MD) and in vitro spectroscopic analysis of the enzyme kinetics and secondary structure to study α-chymotrypsin (CT) conjugated to gold-coated iron oxide MNPs. The latter are functionalized by either carboxylic or amino group moieties to vary the points of enzyme attachment. The MD simulation suggests that application of the stretching force to the CT globule by its amino or carboxylic groups causes shrinkage of the substrate-binding site but little if any changes in the catalytic triad. Consistent with this, in CT conjugated to MNPs by either amino or carboxylic groups, LFMF alters the Michaelis-Menten constant but not the apparent catalytic constant k cat (= V max/[E]o). Irrespective of the point of conjugation to MNPs, the CT secondary structure was affected with nearly complete loss of α-helices and increase in the random structures in LFMF, as shown by attenuated total reflection Fourier transformed infrared spectroscopy. Both the catalytic activity and the protein structure of MNP-CT conjugates restored 3 h after the field exposure. We believe that such remotely actuated systems can find applications in advanced manufacturing, nanomedicine, and other areas.
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Affiliation(s)
- Maxim
M. Veselov
- School
of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Igor V. Uporov
- School
of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Maria V. Efremova
- School
of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
- National
University of Science and Technology “MISIS”, Moscow 119049, Russia
- Department
of Applied Physics, Eindhoven University
of Technology, Eindhoven 5600 MB, The Netherlands
| | - Irina M. Le-Deygen
- School
of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
| | | | - Igor V. Shchetinin
- National
University of Science and Technology “MISIS”, Moscow 119049, Russia
| | | | - Yuri I. Golovin
- School
of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
- G.R.
Derzhavin Tambov State University, Tambov 392000, Russia
| | - Alexander V. Kabanov
- School
of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
- Center
for
Nanotechnology in Drug Delivery, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7362, United States
| | - Natalia L. Klyachko
- School
of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
- Center
for
Nanotechnology in Drug Delivery, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7362, United States
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13
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Nandi T, Ainavarapu SRK. Native Salt Bridges Are a Key Regulator of Ubiquitin's Mechanical Stability. J Phys Chem B 2022; 126:3505-3511. [PMID: 35535497 DOI: 10.1021/acs.jpcb.2c00972] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although it is known that various intramolecular interactions determine protein mechanical stability, a detailed molecular-level understanding of the key regulators of protein mechanical stability is still lacking. Here, we present evidence for salt bridges in ubiquitin as important intramolecular interactions that can affect protein mechanical stability. Ubiquitin has two salt bridges: one relatively surface-exposed (SB1:K11-E34) and the other relatively buried (SB2:K27-D52). Ubiquitin is a reversible post-translational modifier and is stable mechanically (Favgu = 185 pN). On breaking SB1, the mechanical stability of ubiquitin is slightly enhanced (Favgu = 193 pN). In contrast, the mechanical stability significantly decreased upon breaking SB2 (Favgu = 158 pN). These results suggest that SB1 are SB2 are regulators of the mechanical stability of ubiquitin. Interestingly, the mechanical stability decreased further (Favgu = 145 pN) for the double salt bridge (DB) null variant. Monte Carlo simulations elucidate that the main regulating factor is the spontaneous unfolding rate constant (ku0), being the highest for the DB null variant followed by the SB2 null variant, and it remains unaltered for the SB1 null variant, while the native-to-transition-state distance (xu) remains unchanged. Our study provides mechanistic understanding on how two native salt bridges can independently regulate the mechanical stability in a protein, which has implications in designing protein-based robust biomaterials in the future.
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Affiliation(s)
- Tathagata Nandi
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Dr. Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Sri Rama Koti Ainavarapu
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Dr. Homi Bhabha Road, Colaba, Mumbai 400005, India
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14
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Beaussart A, Canonico F, Mazon H, Hidalgo J, Cianférani S, Le Cordier H, Kriznik A, Rahuel-Clermont S. Probing the mechanism of the peroxiredoxin decamer interaction with its reductase sulfiredoxin from the single molecule to the solution scale. NANOSCALE HORIZONS 2022; 7:515-525. [PMID: 35234779 DOI: 10.1039/d2nh00037g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Peroxiredoxins from the Prx1 subfamily (Prx) are highly regulated multifunctional proteins involved in oxidative stress response, redox signaling and cell protection. Prx is a homodimer that associates into a decamer. The monomer C-terminus plays intricate roles in Prx catalytic functions, decamer stability and interaction with its redox partner, the small reductase sulfiredoxin (Srx), that regulates the switching between Prx cellular functions. As only static structures of covalent Prx-Srx complexes have been reported, whether Srx binding dissociates the decameric assembly and how Prx subunit flexibility impacts complex formation are unknown. Here, we assessed the non-covalent interaction mechanism and dynamics in the solution of Saccharomyces cerevisiae Srx with the ten subunits of Prx Tsa1 at the decamer level via a combination of multiscale biophysical approaches including native mass spectrometry. We show that the ten subunits of the decamer can be saturated by ten Srx molecules and that the Tsa1 decamer in complex with Srx does not dissociate in solution. Furthermore, the binding events of atomic force microscopy (AFM) tip-grafted Srx molecules to Tsa1 individual subunits were relevant to the interactions between free molecules in solution. Combined with protein engineering and rapid kinetics, the observation of peculiar AFM force-distance signatures revealed that Tsa1 C-terminus flexibility controls Tsa1/Srx two-step binding and dynamics and determines the force-induced dissociation of Srx from each subunit of the decameric complex in a sequential or concerted mode. This combined approach from the solution to the single-molecule level offers promising prospects for understanding oligomeric protein interactions with their partners.
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Affiliation(s)
| | | | - Hortense Mazon
- Université de Lorraine, CNRS, IMoPA, F-54000 Nancy, France
| | - Jorge Hidalgo
- Université de Lorraine, CNRS, IMoPA, F-54000 Nancy, France
| | - Sarah Cianférani
- Laboratoire de Spectrométrie de Masse BioOrganique, Université de Strasbourg, CNRS, IPHC UMR 7178, 67000 Strasbourg, France
- Infrastructure Nationale de Protéomique ProFI - FR2048 CNRS CEA, 67087 Strasbourg, France
| | | | - Alexandre Kriznik
- Université de Lorraine, CNRS, IMoPA, F-54000 Nancy, France
- Université de Lorraine, CNRS, INSERM, UMS2008 IBSLor, Biophysics and Structural Biology core facility, F-54000 Nancy, France.
| | - Sophie Rahuel-Clermont
- Université de Lorraine, CNRS, IMoPA, F-54000 Nancy, France
- Université de Lorraine, CNRS, INSERM, UMS2008 IBSLor, Biophysics and Structural Biology core facility, F-54000 Nancy, France.
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15
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Gil-Redondo JC, Weber A, Toca-Herrera JL. Measuring (biological) materials mechanics with atomic force microscopy. 3. Mechanical unfolding of biopolymers. Microsc Res Tech 2022; 85:3025-3036. [PMID: 35502131 PMCID: PMC9543778 DOI: 10.1002/jemt.24136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 04/13/2022] [Indexed: 11/28/2022]
Abstract
Biopolymers, such as polynucleotides, polypeptides and polysaccharides, are macromolecules that direct most of the functions in living beings. Studying the mechanical unfolding of biopolymers provides important information about their molecular elasticity and mechanical stability, as well as their energy landscape, which is especially important in proteins, since their three‐dimensional structure is essential for their correct activity. In this primer, we present how to study the mechanical properties of proteins with atomic force microscopy and how to obtain information about their stability and energetic landscape. In particular, we discuss the preparation of polyprotein constructs suitable for AFM single molecule force spectroscopy (SMFS), describe the parameters used in our force‐extension SMFS experiments and the models and equations employed in the analysis of the data. As a practical example, we show the effect of the temperature on the unfolding force, the distance to the transition state, the unfolding rate at zero force, the height of the transition state barrier, and the spring constant of the protein for a construct containing nine repeats of the I27 domain from the muscle protein titin.
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Affiliation(s)
- Juan Carlos Gil-Redondo
- Institute of Biophysics, Department of Nanobiotechnology, University of Natural Resources and Life Sciences Vienna (BOKU), Vienna, Austria
| | - Andreas Weber
- Institute of Biophysics, Department of Nanobiotechnology, University of Natural Resources and Life Sciences Vienna (BOKU), Vienna, Austria
| | - José L Toca-Herrera
- Institute of Biophysics, Department of Nanobiotechnology, University of Natural Resources and Life Sciences Vienna (BOKU), Vienna, Austria
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16
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Nandi T, Koti Ainavarapu SR. Reconstruction of the Free Energy Profile for SUMO1 from Nonequilibrium Single-Molecule Pulling Experiments. J Phys Chem B 2022; 126:2168-2172. [PMID: 35271281 DOI: 10.1021/acs.jpcb.1c08596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Free energy profiles form the cornerstone in the study of protein folding and function. In this study, the free energy profile of SUMO1 protein is directly reconstructed using an extension of the Jarzynski equality from atomic force microscope (AFM) based single-molecule force spectroscopy (SMFS) experiments. SUMO1 is a ubiquitin-like posttranslational modifier protein having a β clamp motif in its structure, imparting it with mechanical stability. We use the Jarzynski equality to obtain the equilibrium free energy profile from repeated nonequilibrium single-molecule pulling experiments. Indeed, the free energy values determined by the Jarzynski equality are lesser than the normal work average at all extensions. The free energy profiles constructed for the two velocities (100 and 400 nm/s) overlap with each other. The unfolding free energy barrier is estimated to be ∼7.5 kcal/mol. We anticipate that the Jarzynski equality can be applied in a similar manner to other ubiquitin-like proteins to extract their differences in the free energy profile, and hence, the effect of sequence diversity of structurally homologous proteins on the free energy landscape can be studied.
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Affiliation(s)
- Tathagata Nandi
- Department of Chemical Sciences, Tata Institute of Fundamental Research Dr. Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Sri Rama Koti Ainavarapu
- Department of Chemical Sciences, Tata Institute of Fundamental Research Dr. Homi Bhabha Road, Colaba, Mumbai 400005, India
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17
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Abstract
Single-molecule magnetic tweezers deliver magnetic force and torque to single target molecules, permitting the study of dynamic changes in biomolecular structures and their interactions. Because the magnetic tweezer setups can generate magnetic fields that vary slowly over tens of millimeters-far larger than the nanometer scale of the single molecule events being observed-this technique can maintain essentially constant force levels during biochemical experiments while generating a biologically meaningful force on the order of 1-100 pN. When using bead-tether constructs to pull on single molecules, smaller magnetic beads and shorter submicrometer tethers improve dynamic response times and measurement precision. In addition, employing high-speed cameras, stronger light sources, and a graphics programming unit permits true high-resolution single-molecule magnetic tweezers that can track nanometer changes in target molecules on a millisecond or even submillisecond time scale. The unique force-clamping capacity of the magnetic tweezer technique provides a way to conduct measurements under near-equilibrium conditions and directly map the energy landscapes underlying various molecular phenomena. High-resolution single-molecule magnetic tweezers can thus be used to monitor crucial conformational changes in single-protein molecules, including those involved in mechanotransduction and protein folding. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Hyun-Kyu Choi
- Wallace H. Coulter Department of Biomedical Engineering and Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Hyun Gyu Kim
- School of Biological Sciences and Institute for Molecular Biology and Genetics, Seoul National University, Seoul, South Korea;
| | - Min Ju Shon
- Department of Physics and School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science & Technology (POSTECH), Pohang, South Korea;
| | - Tae-Young Yoon
- School of Biological Sciences and Institute for Molecular Biology and Genetics, Seoul National University, Seoul, South Korea;
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18
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Yang T, Park C, Rah SH, Shon MJ. Nano-Precision Tweezers for Mechanosensitive Proteins and Beyond. Mol Cells 2022; 45:16-25. [PMID: 35114644 PMCID: PMC8819490 DOI: 10.14348/molcells.2022.2026] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 01/10/2022] [Accepted: 01/12/2022] [Indexed: 11/27/2022] Open
Abstract
Mechanical forces play pivotal roles in regulating cell shape, function, and fate. Key players that govern the mechanobiological interplay are the mechanosensitive proteins found on cell membranes and in cytoskeleton. Their unique nanomechanics can be interrogated using single-molecule tweezers, which can apply controlled forces to the proteins and simultaneously measure the ensuing structural changes. Breakthroughs in high-resolution tweezers have enabled the routine monitoring of nanometer-scale, millisecond dynamics as a function of force. Undoubtedly, the advancement of structural biology will be further fueled by integrating static atomic-resolution structures and their dynamic changes and interactions observed with the force application techniques. In this minireview, we will introduce the general principles of single-molecule tweezers and their recent applications to the studies of force-bearing proteins, including the synaptic proteins that need to be categorized as mechanosensitive in a broad sense. We anticipate that the impact of nano-precision approaches in mechanobiology research will continue to grow in the future.
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Affiliation(s)
- Taehyun Yang
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Celine Park
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Sang-Hyun Rah
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Min Ju Shon
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang 37673, Korea
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19
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Sarkar A. Biosensing, Characterization of Biosensors, and Improved Drug Delivery Approaches Using Atomic Force Microscopy: A Review. FRONTIERS IN NANOTECHNOLOGY 2022. [DOI: 10.3389/fnano.2021.798928] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Since its invention, atomic force microscopy (AFM) has come forth as a powerful member of the “scanning probe microscopy” (SPM) family and an unparallel platform for high-resolution imaging and characterization for inorganic and organic samples, especially biomolecules, biosensors, proteins, DNA, and live cells. AFM characterizes any sample by measuring interaction force between the AFM cantilever tip (the probe) and the sample surface, and it is advantageous over other SPM and electron micron microscopy techniques as it can visualize and characterize samples in liquid, ambient air, and vacuum. Therefore, it permits visualization of three-dimensional surface profiles of biological specimens in the near-physiological environment without sacrificing their native structures and functions and without using laborious sample preparation protocols such as freeze-drying, staining, metal coating, staining, or labeling. Biosensors are devices comprising a biological or biologically extracted material (assimilated in a physicochemical transducer) that are utilized to yield electronic signal proportional to the specific analyte concentration. These devices utilize particular biochemical reactions moderated by isolated tissues, enzymes, organelles, and immune system for detecting chemical compounds via thermal, optical, or electrical signals. Other than performing high-resolution imaging and nanomechanical characterization (e.g., determining Young’s modulus, adhesion, and deformation) of biosensors, AFM cantilever (with a ligand functionalized tip) can be transformed into a biosensor (microcantilever-based biosensors) to probe interactions with a particular receptors of choice on live cells at a single-molecule level (using AFM-based single-molecule force spectroscopy techniques) and determine interaction forces and binding kinetics of ligand receptor interactions. Targeted drug delivery systems or vehicles composed of nanoparticles are crucial in novel therapeutics. These systems leverage the idea of targeted delivery of the drug to the desired locations to reduce side effects. AFM is becoming an extremely useful tool in figuring out the topographical and nanomechanical properties of these nanoparticles and other drug delivery carriers. AFM also helps determine binding probabilities and interaction forces of these drug delivery carriers with the targeted receptors and choose the better agent for drug delivery vehicle by introducing competitive binding. In this review, we summarize contributions made by us and other researchers so far that showcase AFM as biosensors, to characterize other sensors, to improve drug delivery approaches, and to discuss future possibilities.
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20
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Liu Z, Moreira RA, Dujmović A, Liu H, Yang B, Poma AB, Nash MA. Mapping Mechanostable Pulling Geometries of a Therapeutic Anticalin/CTLA-4 Protein Complex. NANO LETTERS 2022; 22:179-187. [PMID: 34918516 PMCID: PMC8759085 DOI: 10.1021/acs.nanolett.1c03584] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 11/03/2021] [Indexed: 05/27/2023]
Abstract
We used single-molecule AFM force spectroscopy (AFM-SMFS) in combination with click chemistry to mechanically dissociate anticalin, a non-antibody protein binding scaffold, from its target (CTLA-4), by pulling from eight different anchor residues. We found that pulling on the anticalin from residue 60 or 87 resulted in significantly higher rupture forces and a decrease in koff by 2-3 orders of magnitude over a force range of 50-200 pN. Five of the six internal anchor points gave rise to complexes significantly more stable than N- or C-terminal anchor points, rupturing at up to 250 pN at loading rates of 0.1-10 nN s-1. Anisotropic network modeling and molecular dynamics simulations helped to explain the geometric dependency of mechanostability. These results demonstrate that optimization of attachment residue position on therapeutic binding scaffolds can provide large improvements in binding strength, allowing for mechanical affinity maturation under shear stress without mutation of binding interface residues.
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Affiliation(s)
- Zhaowei Liu
- Institute
of Physical Chemistry, Department of Chemistry, University of Basel, 4058 Basel, Switzerland
- Department
of Biosystems Science and Engineering, ETH
Zurich, 4058 Basel, Switzerland
| | - Rodrigo A. Moreira
- Biosystems
and Soft Matter Division, Institute of Fundamental
Technological Research, Polish Academy of Sciences, Pawińskiego 5B, 02-106 Warsaw, Poland
| | - Ana Dujmović
- Institute
of Physical Chemistry, Department of Chemistry, University of Basel, 4058 Basel, Switzerland
- Department
of Biosystems Science and Engineering, ETH
Zurich, 4058 Basel, Switzerland
| | - Haipei Liu
- Institute
of Physical Chemistry, Department of Chemistry, University of Basel, 4058 Basel, Switzerland
- Department
of Biosystems Science and Engineering, ETH
Zurich, 4058 Basel, Switzerland
| | - Byeongseon Yang
- Institute
of Physical Chemistry, Department of Chemistry, University of Basel, 4058 Basel, Switzerland
- Department
of Biosystems Science and Engineering, ETH
Zurich, 4058 Basel, Switzerland
| | - Adolfo B. Poma
- Biosystems
and Soft Matter Division, Institute of Fundamental
Technological Research, Polish Academy of Sciences, Pawińskiego 5B, 02-106 Warsaw, Poland
- International
Center for Research on Innovative Biobased Materials (ICRI-BioM)—International
Research Agenda, Lodz University of Technology, Żeromskiego 116, 90-924 Lodz, Poland
| | - Michael A. Nash
- Institute
of Physical Chemistry, Department of Chemistry, University of Basel, 4058 Basel, Switzerland
- Department
of Biosystems Science and Engineering, ETH
Zurich, 4058 Basel, Switzerland
- National
Center for Competence in Research (NCCR) Molecular Systems Engineering, 4058 Basel, Switzerland
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21
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Li J, Li H. New insights into the folding–unfolding mechanism and conformations of cytochrome C. Chem Sci 2022; 13:7498-7508. [PMID: 35872809 PMCID: PMC9241957 DOI: 10.1039/d2sc01126c] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 05/29/2022] [Indexed: 11/21/2022] Open
Abstract
Optical trapping experiments offer new insights into the folding and unfolding of cytochrome C.
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Affiliation(s)
- Jiayu Li
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - Hongbin Li
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
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22
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Affiliation(s)
- Guido Raos
- Department of Chemistry, Materials and Chemical Engineering “G. Natta”, Politecnico di Milano, Via L. Mancinelli 7, I-20131 Milano, Italy
| | - Bruno Zappone
- Consiglio Nazionale delle Ricerche - Istituto di Nanotecnologia (CNR-Nanotec), Via P. Bucci, 33/C, 87036 Rende (CS), Italy
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23
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Hanson BS, Dougan L. Intermediate Structural Hierarchy in Biological Networks Modulates the Fractal Dimension and Force Distribution of Percolating Clusters. Biomacromolecules 2021; 22:4191-4198. [PMID: 34420304 DOI: 10.1021/acs.biomac.1c00751] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Globular protein hydrogels are an emerging class of materials with the potential for rational design, and a generalized understanding of how their network properties emerge from the structure and dynamics of the building block is a key challenge. Here we computationally investigate the effect of intermediate (polymeric) nanoscale structure on the formation of protein hydrogels. We show that changes in both the cross-link topology and flexibility of the polymeric building block lead to changes in the force transmission around the system and provide insight into the dynamic network formation processes. The preassembled intermediate structure provides a novel structural coordinate for the hierarchical modulation of macroscopic network properties, as well as furthering our understanding of the general dynamics of network formation.
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Affiliation(s)
- Benjamin S Hanson
- Physics and Astronomy, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Lorna Dougan
- Physics and Astronomy, University of Leeds, Leeds LS2 9JT, United Kingdom.,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
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24
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Nutritionally induced nanoscale variations in spider silk structural and mechanical properties. J Mech Behav Biomed Mater 2021; 125:104873. [PMID: 34653899 DOI: 10.1016/j.jmbbm.2021.104873] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 09/24/2021] [Accepted: 09/30/2021] [Indexed: 10/20/2022]
Abstract
Spider major ampullate (MA) silk is characterized by high strength and toughness and is adaptable across environments. Experiments depriving spiders of protein have enabled researchers to examine nutritionally induced changes in gene expression, protein structures, and bulk properties of MA silk. However, it has not been elucidated if it varies in a similar way at a nanoscale. Here we used Atomic Force Microscopy (AFM) to simultaneously examine the topographic, structural, and mechanical properties of silks spun by two species of spider, Argiope keyserlingi and Latrodectus hasselti, at a nanoscale when protein fed or deprived. We found height, a measure of localized width, to substantially vary across species and treatments. We also found that Young's modulus, which may be used as an estimate of localized stiffness, decreased with protein deprivation in both species' silk. Our results suggest that nanoscale skin-core structures of A. keyserlingi's MA silk varied significantly across treatments, whereas only slight structural and functional variability was found for L. hasselti's silk. These results largely agreed with examinations of the bulk properties of each species' silk. However, we could not directly attribute the decoupling between protein structures and bulk mechanics in L. hasselti's silk to nanoscale features. Our results advance the understanding of processes inducing skin and core structural variations in spider silks at a nanoscale, which serves to enhance the prospect of developing biomimetic engineering programs.
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25
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Petrosyan R, Narayan A, Woodside MT. Single-Molecule Force Spectroscopy of Protein Folding. J Mol Biol 2021; 433:167207. [PMID: 34418422 DOI: 10.1016/j.jmb.2021.167207] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/11/2021] [Accepted: 08/11/2021] [Indexed: 10/20/2022]
Abstract
The use of force probes to induce unfolding and refolding of single molecules through the application of mechanical tension, known as single-molecule force spectroscopy (SMFS), has proven to be a powerful tool for studying the dynamics of protein folding. Here we provide an overview of what has been learned about protein folding using SMFS, from small, single-domain proteins to large, multi-domain proteins. We highlight the ability of SMFS to measure the energy landscapes underlying folding, to map complex pathways for native and non-native folding, to probe the mechanisms of chaperones that assist with native folding, to elucidate the effects of the ribosome on co-translational folding, and to monitor the folding of membrane proteins.
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Affiliation(s)
- Rafayel Petrosyan
- Department of Physics, University of Alberta, Edmonton, AB T6G 2E1, Canada
| | - Abhishek Narayan
- Department of Physics, University of Alberta, Edmonton, AB T6G 2E1, Canada
| | - Michael T Woodside
- Department of Physics, University of Alberta, Edmonton, AB T6G 2E1, Canada
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26
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van der Sleen LM, Tych KM. Bioconjugation Strategies for Connecting Proteins to DNA-Linkers for Single-Molecule Force-Based Experiments. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:2424. [PMID: 34578744 PMCID: PMC8464727 DOI: 10.3390/nano11092424] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/13/2021] [Accepted: 09/15/2021] [Indexed: 01/10/2023]
Abstract
The mechanical properties of proteins can be studied with single molecule force spectroscopy (SMFS) using optical tweezers, atomic force microscopy and magnetic tweezers. It is common to utilize a flexible linker between the protein and trapped probe to exclude short-range interactions in SMFS experiments. One of the most prevalent linkers is DNA due to its well-defined properties, although attachment strategies between the DNA linker and protein or probe may vary. We will therefore provide a general overview of the currently existing non-covalent and covalent bioconjugation strategies to site-specifically conjugate DNA-linkers to the protein of interest. In the search for a standardized conjugation strategy, considerations include their mechanical properties in the context of SMFS, feasibility of site-directed labeling, labeling efficiency, and costs.
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Affiliation(s)
| | - Katarzyna M. Tych
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, The Netherlands;
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27
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Nie J, Tian F, Zheng B, Wang Z, Zheng P. Exploration of Metal-Ligand Coordination Bonds in Proteins by Single-molecule Force Spectroscopy. CHEM LETT 2021. [DOI: 10.1246/cl.210307] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Jingyuan Nie
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, P. R. China
| | - Fang Tian
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, P. R. China
| | - Bin Zheng
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, P. R. China
| | - Ziyi Wang
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, P. R. China
| | - Peng Zheng
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, P. R. China
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28
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Kumar S, Saha D, Ray D, Abbas S, Aswal VK. Unusual stability of protein molecules in the presence of multivalent counterions. Phys Rev E 2021; 104:L012603. [PMID: 34412269 DOI: 10.1103/physreve.104.l012603] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 07/08/2021] [Indexed: 12/29/2022]
Abstract
Proteins are known to undergo denaturation and form different phases with varying physicochemical parameters. We report unusual stability of bovine serum albumin protein against commonly used denaturants (temperature and surfactant) in the charged reversal reentrant phase, caused by the multivalent counterions. Unlike monovalent counterions, which promote the denaturants' induced protein unfolding, the unfolding is restricted in the presence of multivalent ions. The observations are beyond the scope of general understanding of protein unfolding and are believed to be governed by ion-ion correlations driven strong condensation of the multivalent ions.
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Affiliation(s)
- Sugam Kumar
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Debasish Saha
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Debes Ray
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Sohrab Abbas
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Vinod K Aswal
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.,Homi Bhabha National Institute, Mumbai 400 094, India
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29
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Applications of atomic force microscopy in modern biology. Emerg Top Life Sci 2021; 5:103-111. [PMID: 33600596 DOI: 10.1042/etls20200255] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 12/25/2020] [Accepted: 01/22/2021] [Indexed: 01/20/2023]
Abstract
Single-molecule force spectroscopy (SMFS) is an emerging tool to investigate mechanical properties of biomolecules and their responses to mechanical forces, and one of the most-used techniques for mechanical manipulation is the atomic force microscope (AFM). AFM was invented as an imaging tool which can be used to image biomolecules in sub-molecular resolution in physiological conditions. It can also be used as a molecular force probe for applying mechanical forces on biomolecules. In this brief review, we will provide exciting examples from recent literature which show how the advances in AFM have enabled us to gain deep insights into mechanical properties and mechanobiology of biomolecules. AFM has been applied to study mechanical properties of cells, tissues, microorganisms, viruses as well as biological macromolecules such as proteins. It has found applications in biomedical fields like cancer biology, where it has been used both in the diagnostic phases as well as drug discovery. AFM has been able to answer questions pertaining to mechanosensing by neurons, and mechanical changes in viruses during infection by the viral particles as well as the fundamental processes such as cell division. Fundamental questions related to protein folding have also been answered by SMFS like determination of energy landscape properties of variety of proteins and their correlation with their biological functions. A multipronged approach is needed to diversify the research, as a combination with optical spectroscopy and computer-based steered molecular dynamic simulations along with SMFS can help us gain further insights into the field of biophysics and modern biology.
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30
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Devaux F, Li X, Sluysmans D, Maurizot V, Bakalis E, Zerbetto F, Huc I, Duwez AS. Single-molecule mechanics of synthetic aromatic amide helices: Ultrafast and robust non-dissipative winding. Chem 2021. [DOI: 10.1016/j.chempr.2021.02.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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31
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Rodriguez-Ramos J, Rico F. Determination of calibration parameters of cantilevers of arbitrary shape by finite element analysis. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:045001. [PMID: 34243426 DOI: 10.1063/5.0036263] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 03/14/2021] [Indexed: 06/13/2023]
Abstract
The use of atomic force microscopy in nanomechanical measurements requires accurate calibration of the cantilever's spring constant (kc) and the optical lever sensitivity (OLS). The thermal method, based on the cantilever's thermal fluctuations in fluids, allows estimation of kc in a fast, non-invasive mode. However, differences in the cantilever geometry and mounting angle require the knowledge of three correction factors to get a good estimation of kc: the contribution of the oscillation mode to the total amplitude, the shape difference between the free and end-loaded configurations, and the tilt of the cantilever with respect to the measured surface. While the correction factors for traditional rectangular and V-shaped cantilever geometries have been reported, they must be determined for cantilevers with non-traditional geometries and large tips. Here, we develop a method based on finite element analysis to estimate the correction factors of cantilevers with arbitrary geometry and tip dimensions. The method relies on the numerical computation of the effective cantilever mass. The use of the correction factor for rectangular geometries in our model cantilever (PFQNM-LC) will lead to values underestimated by 16%. In contrast, experiments using pre-calibrated cantilevers revealed a maximum uncertainty below 5% in the estimation of the OLS, verifying our approach.
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Affiliation(s)
| | - Felix Rico
- Aix-Marseille University, INSERM, CNRS, LAI, 13009 Marseille, France
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32
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Abstract
Multiple gram-negative bacteria encode type III secretion systems (T3SS) that allow them to inject effector proteins directly into host cells to facilitate colonization. To be secreted, effector proteins must be at least partially unfolded to pass through the narrow needle-like channel (diameter <2 nm) of the T3SS. Fusion of effector proteins to tightly packed proteins-such as GFP, ubiquitin, or dihydrofolate reductase (DHFR)-impairs secretion and results in obstruction of the T3SS. Prior observation that unfolding can become rate-limiting for secretion has led to the model that T3SS effector proteins have low thermodynamic stability, facilitating their secretion. Here, we first show that the unfolding free energy ([Formula: see text]) of two Salmonella effector proteins, SptP and SopE2, are 6.9 and 6.0 kcal/mol, respectively, typical for globular proteins and similar to published [Formula: see text] for GFP, ubiquitin, and DHFR. Next, we mechanically unfolded individual SptP and SopE2 molecules by atomic force microscopy (AFM)-based force spectroscopy. SptP and SopE2 unfolded at low force (F unfold ≤ 17 pN at 100 nm/s), making them among the most mechanically labile proteins studied to date by AFM. Moreover, their mechanical compliance is large, as measured by the distance to the transition state (Δx ‡ = 1.6 and 1.5 nm for SptP and SopE2, respectively). In contrast, prior measurements of GFP, ubiquitin, and DHFR show them to be mechanically robust (F unfold > 80 pN) and brittle (Δx ‡ < 0.4 nm). These results suggest that effector protein unfolding by T3SS is a mechanical process and that mechanical lability facilitates efficient effector protein secretion.
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33
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Casar JR, McLellan CA, Siefe C, Dionne JA. Lanthanide-Based Nanosensors: Refining Nanoparticle Responsiveness for Single Particle Imaging of Stimuli. ACS PHOTONICS 2021; 8:3-17. [PMID: 34307765 PMCID: PMC8297747 DOI: 10.1021/acsphotonics.0c00894] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Lanthanide nanoparticles (LNPs) are promising sensors of chemical, mechanical, and temperature changes; they combine the narrow-spectral emission and long-lived excited states of individual lanthanide ions with the high spatial resolution and controlled energy transfer of nanocrystalline architectures. Despite considerable progress in optimizing LNP brightness and responsiveness for dynamic sensing, detection of stimuli with a spatial resolution approaching that of individual nanoparticles remains an outstanding challenge. Here, we highlight the existing capabilities and outstanding challenges of LNP sensors, en-route to nanometer-scale, single particle sensor resolution. First, we summarize LNP sensor read-outs, including changes in emission wavelength, lifetime, intensity, and spectral ratiometric values that arise from modified energy transfer networks within nanoparticles. Then, we describe the origins of LNP sensor imprecision, including sensitivity to competing conditions, interparticle heterogeneities, such as the concentration and distribution of dopant ions, and measurement noise. Motivated by these sources of signal variance, we describe synthesis characterization feedback loops to inform and improve sensor precision, and introduce noise-equivalent sensitivity as a figure of merit of LNP sensors. Finally, we project the magnitudes of chemical and pressure stimulus resolution achievable with single LNPs at nanoscale resolution. Our perspective provides a roadmap for translating ensemble LNP sensing capabilities to the single particle level, enabling nanometer-scale sensing in biology, medicine, and sustainability.
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Affiliation(s)
- Jason R Casar
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Claire A McLellan
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Chris Siefe
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Jennifer A Dionne
- Department of Materials Science and Engineering and Department of Radiology, Molecular Imaging Program, Stanford University, Stanford, California 94305, United States
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34
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Li S, Wang X, Li Z, Huang Z, Lin S, Hu J, Tu Y. Research progress of single molecule force spectroscopy technology based on atomic force microscopy in polymer materials: Structure, design strategy and probe modification. NANO SELECT 2021. [DOI: 10.1002/nano.202000235] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Shi Li
- Guangzhou Institute of Chemistry Chinese Academy of Sciences Guangzhou 510650 PR China
- University of Chinese Academy of Sciences Beijing 100049 PR China
| | - Xiao Wang
- Guangzhou Institute of Chemistry Chinese Academy of Sciences Guangzhou 510650 PR China
- University of Chinese Academy of Sciences Beijing 100049 PR China
| | - Zhihua Li
- Guangzhou Institute of Chemistry Chinese Academy of Sciences Guangzhou 510650 PR China
- University of Chinese Academy of Sciences Beijing 100049 PR China
| | - Zhenzhu Huang
- Guangzhou Institute of Chemistry Chinese Academy of Sciences Guangzhou 510650 PR China
- Guangdong Provincial Key Laboratory of Organic Polymer Materials for Electronics Guangzhou 510650 PR China
- CAS Engineering Laboratory for Special Fine Chemicals Guangzhou 510650 PR China
- Incubator of Nanxiong CAS Co., Ltd. Nanxiong 512400 PR China
- University of Chinese Academy of Sciences Beijing 100049 PR China
| | - Shudong Lin
- Guangzhou Institute of Chemistry Chinese Academy of Sciences Guangzhou 510650 PR China
- Guangdong Provincial Key Laboratory of Organic Polymer Materials for Electronics Guangzhou 510650 PR China
- CAS Engineering Laboratory for Special Fine Chemicals Guangzhou 510650 PR China
- Incubator of Nanxiong CAS Co., Ltd. Nanxiong 512400 PR China
- University of Chinese Academy of Sciences Beijing 100049 PR China
| | - Jiwen Hu
- Guangzhou Institute of Chemistry Chinese Academy of Sciences Guangzhou 510650 PR China
- Guangdong Provincial Key Laboratory of Organic Polymer Materials for Electronics Guangzhou 510650 PR China
- CAS Engineering Laboratory for Special Fine Chemicals Guangzhou 510650 PR China
- Incubator of Nanxiong CAS Co., Ltd. Nanxiong 512400 PR China
- University of Chinese Academy of Sciences Beijing 100049 PR China
| | - Yuanyuan Tu
- Guangzhou Institute of Chemistry Chinese Academy of Sciences Guangzhou 510650 PR China
- Guangdong Provincial Key Laboratory of Organic Polymer Materials for Electronics Guangzhou 510650 PR China
- CAS Engineering Laboratory for Special Fine Chemicals Guangzhou 510650 PR China
- Incubator of Nanxiong CAS Co., Ltd. Nanxiong 512400 PR China
- University of Chinese Academy of Sciences Beijing 100049 PR China
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35
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Casuso I, Redondo-Morata L, Rico F. Biological physics by high-speed atomic force microscopy. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2020; 378:20190604. [PMID: 33100165 PMCID: PMC7661283 DOI: 10.1098/rsta.2019.0604] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
While many fields have contributed to biological physics, nanotechnology offers a new scale of observation. High-speed atomic force microscopy (HS-AFM) provides nanometre structural information and dynamics with subsecond resolution of biological systems. Moreover, HS-AFM allows us to measure piconewton forces within microseconds giving access to unexplored, fast biophysical processes. Thus, HS-AFM provides a tool to nourish biological physics through the observation of emergent physical phenomena in biological systems. In this review, we present an overview of the contribution of HS-AFM, both in imaging and force spectroscopy modes, to the field of biological physics. We focus on examples in which HS-AFM observations on membrane remodelling, molecular motors or the unfolding of proteins have stimulated the development of novel theories or the emergence of new concepts. We finally provide expected applications and developments of HS-AFM that we believe will continue contributing to our understanding of nature, by serving to the dialogue between biology and physics. This article is part of a discussion meeting issue 'Dynamic in situ microscopy relating structure and function'.
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Affiliation(s)
- Ignacio Casuso
- Aix-Marseile University, Inserm, CNRS, LAI, 163 Av. de Luminy, 13009 Marseille, France
| | - Lorena Redondo-Morata
- Center for Infection and Immunity of Lille, INSERM U1019, CNRS UMR 8204, 59000 Lille, France
| | - Felix Rico
- Aix-Marseile University, Inserm, CNRS, LAI, 163 Av. de Luminy, 13009 Marseille, France
- e-mail:
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36
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Bergues-Pupo AE, Lipowsky R, Vila Verde A. Unfolding mechanism and free energy landscape of single, stable, alpha helices at low pull speeds. SOFT MATTER 2020; 16:9917-9928. [PMID: 33030193 DOI: 10.1039/d0sm01166e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Single alpha helices (SAHs) stable in isolated form are often found in motor proteins where they bridge functional domains. Understanding the mechanical response of SAHs is thus critical to understand their function. The quasi-static force-extension relation of a small number of SAHs is known from single-molecule experiments. Unknown, or still controversial, are the molecular scale details behind those observations. We show that the deformation mechanism of SAHs pulled from the termini at pull speeds approaching the quasi-static limit differs from that of typical helices found in proteins, which are stable only when interacting with other protein domains. Using molecular dynamics simulations with atomistic resolution at low pull speeds previously inaccessible to simulation, we show that SAHs start unfolding from the termini at all pull speeds we investigated. Unfolding proceeds residue-by-residue and hydrogen bond breaking is not the main event determining the barrier to unfolding. We use the molecular simulation data to test the cooperative sticky chain model. This model yields excellent fits of the force-extension curves and quantifies the distance, xE = 0.13 nm, to the transition state, the natural frequency of bond vibration, ν0 = 0.82 ns-1, and the height, V0 = 2.9 kcal mol-1, of the free energy barrier associated with the deformation of single residues. Our results demonstrate that the sticky chain model could advantageously be used to analyze experimental force-extension curves of SAHs and other biopolymers.
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Affiliation(s)
- Ana Elisa Bergues-Pupo
- Max Planck Institute of Colloids and Interfaces, Department of Theory & Bio-Systems, Am Mühlenberg 1, 14476 Potsdam, Germany.
| | - Reinhard Lipowsky
- Max Planck Institute of Colloids and Interfaces, Department of Theory & Bio-Systems, Am Mühlenberg 1, 14476 Potsdam, Germany.
| | - Ana Vila Verde
- Max Planck Institute of Colloids and Interfaces, Department of Theory & Bio-Systems, Am Mühlenberg 1, 14476 Potsdam, Germany.
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37
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Lehmann K, Shayegan M, Blab GA, Forde NR. Optical Tweezers Approaches for Probing Multiscale Protein Mechanics and Assembly. Front Mol Biosci 2020; 7:577314. [PMID: 33134316 PMCID: PMC7573139 DOI: 10.3389/fmolb.2020.577314] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 08/27/2020] [Indexed: 01/09/2023] Open
Abstract
Multi-step assembly of individual protein building blocks is key to the formation of essential higher-order structures inside and outside of cells. Optical tweezers is a technique well suited to investigate the mechanics and dynamics of these structures at a variety of size scales. In this mini-review, we highlight experiments that have used optical tweezers to investigate protein assembly and mechanics, with a focus on the extracellular matrix protein collagen. These examples demonstrate how optical tweezers can be used to study mechanics across length scales, ranging from the single-molecule level to fibrils to protein networks. We discuss challenges in experimental design and interpretation, opportunities for integration with other experimental modalities, and applications of optical tweezers to current questions in protein mechanics and assembly.
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Affiliation(s)
- Kathrin Lehmann
- Department of Physics, Simon Fraser University, Burnaby, BC, Canada.,Soft Condensed Matter and Biophysics, Utrecht University, Utrecht, Netherlands
| | - Marjan Shayegan
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, United States
| | - Gerhard A Blab
- Soft Condensed Matter and Biophysics, Utrecht University, Utrecht, Netherlands
| | - Nancy R Forde
- Department of Physics, Simon Fraser University, Burnaby, BC, Canada.,Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada.,Department of Chemistry, Simon Fraser University, Burnaby, BC, Canada.,Centre for Cell Biology, Development and Disease (C2D2), Simon Fraser University, Burnaby, BC, Canada
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38
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Benedito M, Manca F, Palla PL, Giordano S. Rate-dependent force-extension models for single-molecule force spectroscopy experiments. Phys Biol 2020; 17:056002. [PMID: 32464604 DOI: 10.1088/1478-3975/ab97a8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Single-molecule force spectroscopy techniques allow for the measurement of several static and dynamic features of macromolecules of biological origin. In particular, atomic force microscopy, used with a variable pulling rate, provides valuable information on the folding/unfolding dynamics of proteins. We propose here two different models able to describe the out-of-equilibrium statistical mechanics of a chain composed of bistable units. These latter represent the protein domains, which can be either folded or unfolded. Both models are based on the Langevin approach and their implementation allows for investigating the effect of the pulling rate and of the device intrinsic elasticity on the chain unfolding response. The theoretical results (both analytical and numerical) have been compared with experimental data concerning the unfolding of the titin and filamin proteins, eventually obtaining a good agreement over a large range of the pulling rates.
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Affiliation(s)
- Manon Benedito
- Institute of Electronics, Microelectronics and Nanotechnology, UMR 8520, Univ. Lille, CNRS, Centrale Lille, ISEN, Univ. Valenciennes, LIA LICS/LEMAC, 59000 Lille, France
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39
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Hanson BS, Dougan L. Network Growth and Structural Characteristics of Globular Protein Hydrogels. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c00890] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Benjamin S. Hanson
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
| | - Lorna Dougan
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K
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40
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Hughes MDG, Cussons S, Mahmoudi N, Brockwell DJ, Dougan L. Single molecule protein stabilisation translates to macromolecular mechanics of a protein network. SOFT MATTER 2020; 16:6389-6399. [PMID: 32578583 DOI: 10.1039/c9sm02484k] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Folded globular proteins are attractive building blocks for biopolymer-based materials, as their mechanically resistant structures carry out diverse biological functionality. While much is now understood about the mechanical response of single folded proteins, a major challenge is to understand and predictably control how single protein mechanics translates to the collective response of a network of connected folded proteins. Here, by utilising the binding of maltose to hydrogels constructed from photo-chemically cross-linked maltose binding protein (MBP), we investigate the effects of protein stabilisation at the molecular level on the macroscopic mechanical and structural properties of a protein-based hydrogel. Rheological measurements show an enhancement in the mechanical strength and energy dissipation of MBP hydrogels in the presence of maltose. Circular dichroism spectroscopy and differential scanning calorimetry measurements show that MBP remains both folded and functional in situ. By coupling these mechanical measurements with mesoscopic structural information obtained by small angle scattering, we propose an occupation model in which higher proportions of stabilised, ligand occupied, protein building blocks translate their increased stability to the macroscopic properties of the hydrogel network. This provides powerful opportunities to exploit environmentally responsive folded protein-based biomaterials for many broad applications.
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Affiliation(s)
- Matt D G Hughes
- School of Physics and Astronomy, Faculty of Engineering and Physical Sciences, University of Leeds, Leeds, UK.
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41
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Lv J, Li Y, Zhou K, Guo P, Liu Y, Ding K, Li K, Zhong C, Xiao B. Force spectra of single bacterial amyloid CsgA nanofibers. RSC Adv 2020; 10:21986-21992. [PMID: 35516640 PMCID: PMC9054517 DOI: 10.1039/d0ra02749a] [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: 03/25/2020] [Accepted: 06/03/2020] [Indexed: 01/04/2023] Open
Abstract
CsgA is a major protein subunit of Escherichia coli biofilms and plays key roles in bacterial adhesion and invasion. CsgA proteins can self-assemble into amyloid nanofibers, characterized by their hierarchical structures across multiple length scales, outstanding strength and their structural robustness under harsh environments. Here, magnetic tweezers were used to study the force spectra of CsgA protein at fibril levels. The two ends of a single nanofiber were directly connected between a magnetic bead and a glass slide using a previously reported tag-free method. We showed that a wormlike chain model could be applied to fit the typical force–extension curves of CsgA nanofibers and to estimate accordingly the mechanical properties. The bending stiffness of nanofibers increased with increasing diameters. The changes in extension of single CsgA fibers were found to be up to 17 fold that of the original length, indicating exceptional tensile properties. Our results provide new insights into the tensile properties of bacterial amyloid nanofibers and highlight the ultrahigh structural stability of the Escherichia coli biofilms. Magnetic tweezers were used to study the force spectra of CsgA, a major protein subunit of Escherichia coli biofilms, at fibril level.![]()
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Affiliation(s)
- Jingqi Lv
- Joint International Research Laboratory of Synthetic Biology and Medicine, School of Biology and Biological Engineering, South China University of Technology Guangzhou 510006 China
| | - Yingfeng Li
- Materials and Physical Biology Division, School of Physical Science and Technology, ShanghaiTech University Shanghai 201210 China
| | - Kai Zhou
- Joint International Research Laboratory of Synthetic Biology and Medicine, School of Biology and Biological Engineering, South China University of Technology Guangzhou 510006 China
| | - Pei Guo
- Joint International Research Laboratory of Synthetic Biology and Medicine, School of Biology and Biological Engineering, South China University of Technology Guangzhou 510006 China
| | - Yang Liu
- Joint International Research Laboratory of Synthetic Biology and Medicine, School of Biology and Biological Engineering, South China University of Technology Guangzhou 510006 China
| | - Ke Ding
- Joint International Research Laboratory of Synthetic Biology and Medicine, School of Biology and Biological Engineering, South China University of Technology Guangzhou 510006 China
| | - Ke Li
- Materials and Physical Biology Division, School of Physical Science and Technology, ShanghaiTech University Shanghai 201210 China
| | - Chao Zhong
- Materials and Physical Biology Division, School of Physical Science and Technology, ShanghaiTech University Shanghai 201210 China
| | - Botao Xiao
- Joint International Research Laboratory of Synthetic Biology and Medicine, School of Biology and Biological Engineering, South China University of Technology Guangzhou 510006 China .,School of Physics, Huazhong University of Science and Technology Wuhan 430074 China
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42
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Chetrit E, Meroz Y, Klausner Z, Berkovich R. Correlations within polyprotein forced unfolding dwell-times introduce sequential dependency. J Struct Biol 2020; 210:107495. [PMID: 32173465 DOI: 10.1016/j.jsb.2020.107495] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 02/15/2020] [Accepted: 03/11/2020] [Indexed: 02/06/2023]
Abstract
Polyproteins, comprised from proteins arrayed in tandem, respond to mechanical loads through partial unfolding and extension. This response to tension that enables their physiological function is related to the ability to dynamically regulate their elasticity. The unique arrangement of their individual mechanical components (proteins and polymeric linkers), and the interactions between them eventually determines their performance. The sequential unfolding-times within a polyprotein are inherently assumed to be independent and identically distributed (iid), thus expected to follow an exponential distribution. Nevertheless, a large body of literature using single molecule force spectroscopy (SMFS) provides evidence that forced unfolding-times of N proteins within a polyprotein do not follow the exponential distribution. Here we use SMFS with Atomic Force Microscopy to measure the unfolding kinetics of Poly-(I91)8 at 180 pN. The unfolding time-intervals were statistically analysed using three common approaches, all exhibiting an N-effect: hierarchical behavior with non-identical unfolding time distributions. Using continuous time random walk approach indicates that the unfolding times display subdiffusive features. Put together with free-energy reconstruction of the whole unfolding polyprotein, we provide physical explanation for this nontrivial behavior, according to which the elongating polypeptide chain with each unfolding event intervenes with the sequential unfolding probabilities and correlates them.
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Affiliation(s)
- Einat Chetrit
- Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Yasmine Meroz
- School of Plant Science and Food Security, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Ziv Klausner
- Department of Applied Mathematics, Israel Institute for Biological Research, P.O. Box 19, Ness-Ziona 7410001, 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.
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43
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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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44
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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.
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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
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45
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Corsetti F, Alonso-Caballero A, Poly S, Perez-Jimenez R, Artacho E. Entropic bonding of the type 1 pilus from experiment and simulation. ROYAL SOCIETY OPEN SCIENCE 2020; 7:200183. [PMID: 32431906 PMCID: PMC7211842 DOI: 10.1098/rsos.200183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 03/19/2020] [Indexed: 06/11/2023]
Abstract
The type 1 pilus is a bacterial filament consisting of a long coiled proteic chain of subunits joined together by non-covalent bonding between complementing β -strands. Its strength and structural stability are critical for its anchoring function in uropathogenic Escherichia coli bacteria. The pulling and unravelling of the FimG subunit of the pilus was recently studied by atomic force microscopy experiments and steered molecular dynamics simulations (Alonso-Caballero et al. 2018 Nat. Commun. 9, 2758. (doi:10.1038/s41467-018-05107-6)). In this work, we perform a quantitative comparison between experiment and simulation, showing a good agreement in the underlying work values for the unfolding. The simulation results are then used to estimate the free energy difference for the detachment of FimG from the complementing strand of the neighbouring subunit in the chain, FimF. Finally, we show that the large free energy difference for the unravelling and detachment of the subunits which leads to the high stability of the chain is entirely entropic in nature.
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Affiliation(s)
- Fabiano Corsetti
- Department of Materials, Imperial College London, London SW7 2AZ, UK
- Department of Physics, Imperial College London, London SW7 2AZ, UK
- The Thomas Young Centre for Theory and Simulation of Materials, Imperial College London, London SW7 2AZ, UK
- CIC nanoGUNE, 20018 Donostia-San Sebastián, Spain
| | - Alvaro Alonso-Caballero
- CIC nanoGUNE, 20018 Donostia-San Sebastián, Spain
- Department of Biological Sciences, Columbia University, NY 10027, USA
| | - Simon Poly
- CIC nanoGUNE, 20018 Donostia-San Sebastián, Spain
- Chimie et Biologie des Membranes et des Nanoobjets CBMN, Université de Bordeaux, 33600 Pessac, France
| | - Raul Perez-Jimenez
- CIC nanoGUNE, 20018 Donostia-San Sebastián, Spain
- Basque Foundation for Science Ikerbasque, 48011 Bilbao, Spain
| | - Emilio Artacho
- CIC nanoGUNE, 20018 Donostia-San Sebastián, Spain
- Basque Foundation for Science Ikerbasque, 48011 Bilbao, Spain
- Theory of Condensed Matter, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK
- Donostia International Physics Center DIPC, 20018 Donostia-San Sebastián, Spain
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46
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Bao Y, Luo Z, Cui S. Environment-dependent single-chain mechanics of synthetic polymers and biomacromolecules by atomic force microscopy-based single-molecule force spectroscopy and the implications for advanced polymer materials. Chem Soc Rev 2020; 49:2799-2827. [PMID: 32236171 DOI: 10.1039/c9cs00855a] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
"The Tao begets the One. One begets all things of the world." This quote from Tao Te Ching is still inspiring for scientists in chemistry and materials science: The "One" can refer to a single molecule. A macroscopic material is composed of numerous molecules. Although the relationship between the properties of the single molecule and macroscopic material is not well understood yet, it is expected that a deeper understanding of the single-chain mechanics of macromolecules will certainly facilitate the development of materials science. Atomic force microscopy-based single-molecule force spectroscopy (AFM-SMFS) has been exploited extensively as a powerful tool to study the single-chain behaviors of macromolecules. In this review, we summarize the recent advances in the emerging field of environment-dependent single-chain mechanics of synthetic polymers and biomacromolecules by means of AFM-SMFS. First, the single-chain inherent elasticities of several typical linear macromolecules are introduced, which are also confirmed by one of three polymer models with theoretical elasticities of the corresponding macromolecules obtained from quantum mechanical (QM) calculations. Then, the effects of the external environments on the single-chain mechanics of synthetic polymers and biomacromolecules are reviewed. Finally, the impacts of single-chain mechanics of macromolecules on the development of polymer science especially polymer materials are illustrated.
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Affiliation(s)
- Yu Bao
- Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China.
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47
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Sluysmans D, Willet N, Thevenot J, Lecommandoux S, Duwez AS. Single-molecule mechanical unfolding experiments reveal a critical length for the formation of α-helices in peptides. NANOSCALE HORIZONS 2020; 5:671-678. [PMID: 32226978 DOI: 10.1039/d0nh00036a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
α-Helix is the most predominant secondary structure in proteins and supports many functions in biological machineries. The conformation of the helix is dictated by many factors such as its primary sequence, intramolecular interactions, or the effect of the close environment. Several computational studies have proposed that there is a critical maximum length for the formation of intact compact helical structures, supporting the fact that most intact α-helices in proteins are constituted of a small number of amino acids. To obtain a detailed picture on the formation of α-helices in peptides and their mechanical stability, we have synthesized a long homopolypeptide of about 90 amino acids, poly(γ-benzyl-l-glutamate), and investigated its mechanical behaviour by AFM-based single-molecule force spectroscopy. The characteristic plateaus observed in the force-extension curves reveal the unfolding of a series of small helices (from 1 to 4) of about 20 amino acid residues connected to each other, rather than a long helix of 90 residues. Our results suggest the formation of a tertiary structure made of short helices with kinks, instead of an intact compact helical structure for sequences of more than 20 amino acid residues. To our knowledge, this is the first experimental evidence supporting the concept of a helical critical length previously proposed by several computational studies.
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Affiliation(s)
- Damien Sluysmans
- Molecular Systems Research Unit, University of Liège, Sart-Tilman B6a, 4000 Liège, Belgium.
| | - Nicolas Willet
- Molecular Systems Research Unit, University of Liège, Sart-Tilman B6a, 4000 Liège, Belgium. and Univ. Bordeaux, CNRS, Bordeaux INP, LCPO, UMR 5629, F-33600, Pessac, France
| | - Julie Thevenot
- Univ. Bordeaux, CNRS, Bordeaux INP, LCPO, UMR 5629, F-33600, Pessac, France
| | | | - Anne-Sophie Duwez
- Molecular Systems Research Unit, University of Liège, Sart-Tilman B6a, 4000 Liège, Belgium.
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Balijepalli AS, Sabatelle RC, Chen M, Suki B, Grinstaff MW. A Synthetic Bioinspired Carbohydrate Polymer with Mucoadhesive Properties. Angew Chem Int Ed Engl 2020; 59:704-710. [PMID: 31701611 PMCID: PMC7754715 DOI: 10.1002/anie.201911720] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 10/17/2019] [Indexed: 01/26/2023]
Abstract
Mucoadhesive polymers are of significant interest to the pharmaceutical, medical device, and cosmetic industries. Polysaccharides possessing charged functional groups, such as chitosan, are known for mucoadhesive properties but suffer from poor chemical definition and solubility, while the chemical synthesis of polysaccharides is challenging with few reported examples of synthetic carbohydrate polymers with engineered-in ionic functionality. We report the design, synthesis, and evaluation of a synthetic, cationic, enantiopure carbohydrate polymer inspired by the structure of chitosan. These water-soluble, cytocompatible polymers are prepared via an anionic ring-opening polymerization of a bicyclic β-lactam sugar monomer. The synthetic method provides control over the site of amine functionalization and the length of the polymer while providing narrow dispersities. These well-defined polymers are mucoadhesive as documented in single-molecule scale (AFM), bulk solution phase (FRAP), and ex vivo tissue experiments. Polymer length and functionality affects bioactivity as long, charged polymers display higher mucoadhesivity than long, neutral polymers or short, charged polymers.
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Affiliation(s)
- Anant S Balijepalli
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston, MA, 02215, USA
| | - Robert C Sabatelle
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston, MA, 02215, USA
| | - Mingfu Chen
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston, MA, 02215, USA
| | - Bela Suki
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston, MA, 02215, USA
| | - Mark W Grinstaff
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston, MA, 02215, USA
- Department of Chemistry, Boston University, 712 Beacon Street, Boston, MA, 02215, USA
- School of Medicine, Boston University, 72 East Concord Street, Boston, MA, 02118, USA
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Li M, Xi N, Wang Y, Liu L. Atomic Force Microscopy as a Powerful Multifunctional Tool for Probing the Behaviors of Single Proteins. IEEE Trans Nanobioscience 2020; 19:78-99. [DOI: 10.1109/tnb.2019.2954099] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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50
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Balijepalli AS, Sabatelle RC, Chen M, Suki B, Grinstaff MW. A Synthetic Bioinspired Carbohydrate Polymer with Mucoadhesive Properties. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201911720] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Anant S. Balijepalli
- Department of Biomedical Engineering Boston University 44 Cummington Mall Boston MA 02215 USA
| | - Robert C. Sabatelle
- Department of Biomedical Engineering Boston University 44 Cummington Mall Boston MA 02215 USA
| | - Mingfu Chen
- Department of Biomedical Engineering Boston University 44 Cummington Mall Boston MA 02215 USA
| | - Bela Suki
- Department of Biomedical Engineering Boston University 44 Cummington Mall Boston MA 02215 USA
| | - Mark W. Grinstaff
- Department of Biomedical Engineering Boston University 44 Cummington Mall Boston MA 02215 USA
- Department of Chemistry Boston University 712 Beacon Street Boston MA 02215 USA
- School of Medicine Boston University 72 East Concord Street Boston MA 02118 USA
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