1
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Negi H, Ravichandran A, Dasgupta P, Reddy S, Das R. Plasticity of the proteasome-targeting signal Fat10 enhances substrate degradation. eLife 2024; 13:e91122. [PMID: 38984715 DOI: 10.7554/elife.91122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 07/09/2024] [Indexed: 07/11/2024] Open
Abstract
The proteasome controls levels of most cellular proteins, and its activity is regulated under stress, quiescence, and inflammation. However, factors determining the proteasomal degradation rate remain poorly understood. Proteasome substrates are conjugated with small proteins (tags) like ubiquitin and Fat10 to target them to the proteasome. It is unclear if the structural plasticity of proteasome-targeting tags can influence substrate degradation. Fat10 is upregulated during inflammation, and its substrates undergo rapid proteasomal degradation. We report that the degradation rate of Fat10 substrates critically depends on the structural plasticity of Fat10. While the ubiquitin tag is recycled at the proteasome, Fat10 is degraded with the substrate. Our results suggest significantly lower thermodynamic stability and faster mechanical unfolding in Fat10 compared to ubiquitin. Long-range salt bridges are absent in the Fat10 structure, creating a plastic protein with partially unstructured regions suitable for proteasome engagement. Fat10 plasticity destabilizes substrates significantly and creates partially unstructured regions in the substrate to enhance degradation. NMR-relaxation-derived order parameters and temperature dependence of chemical shifts identify the Fat10-induced partially unstructured regions in the substrate, which correlated excellently to Fat10-substrate contacts, suggesting that the tag-substrate collision destabilizes the substrate. These results highlight a strong dependence of proteasomal degradation on the structural plasticity and thermodynamic properties of the proteasome-targeting tags.
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Affiliation(s)
- Hitendra Negi
- National Center for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
- SASTRA University, Thirumalaisamudram, Thanjavur, India
| | - Aravind Ravichandran
- National Center for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
- SASTRA University, Thirumalaisamudram, Thanjavur, India
| | - Pritha Dasgupta
- National Center for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Shridivya Reddy
- National Center for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Ranabir Das
- National Center for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
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2
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Hughes MDG, Cussons S, Hanson BS, Cook KR, Feller T, Mahmoudi N, Baker DL, Ariëns R, Head DA, Brockwell DJ, Dougan L. Building block aspect ratio controls assembly, architecture, and mechanics of synthetic and natural protein networks. Nat Commun 2023; 14:5593. [PMID: 37696784 PMCID: PMC10495373 DOI: 10.1038/s41467-023-40921-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 08/16/2023] [Indexed: 09/13/2023] Open
Abstract
Fibrous networks constructed from high aspect ratio protein building blocks are ubiquitous in nature. Despite this ubiquity, the functional advantage of such building blocks over globular proteins is not understood. To answer this question, we engineered hydrogel network building blocks with varying numbers of protein L domains to control the aspect ratio. The mechanical and structural properties of photochemically crosslinked protein L networks were then characterised using shear rheology and small angle neutron scattering. We show that aspect ratio is a crucial property that defines network architecture and mechanics, by shifting the formation from translationally diffusion dominated to rotationally diffusion dominated. Additionally, we demonstrate that a similar transition is observed in the model living system: fibrin blood clot networks. The functional advantages of this transition are increased mechanical strength and the rapid assembly of homogenous networks above a critical protein concentration, crucial for in vivo biological processes such as blood clotting. In addition, manipulating aspect ratio also provides a parameter in the design of future bio-mimetic and bio-inspired materials.
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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
| | - Sophie Cussons
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Benjamin S Hanson
- School of Physics and Astronomy, Faculty of Engineering and Physical Sciences, University of Leeds, Leeds, UK
| | - Kalila R Cook
- School of Physics and Astronomy, Faculty of Engineering and Physical Sciences, University of Leeds, Leeds, UK
| | - Tímea Feller
- Leeds Institute of Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, UK
| | - Najet Mahmoudi
- ISIS Neutron and Muon Spallation Source, STFC Rutherford Appleton Laboratory, Oxfordshire, UK
| | - Daniel L Baker
- School of Physics and Astronomy, Faculty of Engineering and Physical Sciences, University of Leeds, Leeds, UK
| | - Robert Ariëns
- Leeds Institute of Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, UK
| | - David A Head
- School of Computing, Faculty of Engineering and Physical Science, University of Leeds, Leeds, UK
| | - David J Brockwell
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Lorna Dougan
- School of Physics and Astronomy, Faculty of Engineering and Physical Sciences, University of Leeds, Leeds, UK.
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK.
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3
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Kaynak BT, Dahmani ZL, Doruker P, Banerjee A, Yang SH, Gordon R, Itzhaki LS, Bahar I. Cooperative mechanics of PR65 scaffold underlies the allosteric regulation of the phosphatase PP2A. Structure 2023; 31:607-618.e3. [PMID: 36948205 PMCID: PMC10164121 DOI: 10.1016/j.str.2023.02.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 01/25/2023] [Accepted: 02/23/2023] [Indexed: 03/24/2023]
Abstract
PR65, a horseshoe-shaped scaffold composed of 15 HEAT (observed in Huntingtin, elongation factor 3, protein phosphatase 2A, and the yeast kinase TOR1) repeats, forms, together with catalytic and regulatory subunits, the heterotrimeric protein phosphatase PP2A. We examined the role of PR65 in enabling PP2A enzymatic activity with computations at various levels of complexity, including hybrid approaches that combine full-atomic and elastic network models. Our study points to the high flexibility of this scaffold allowing for end-to-end distance fluctuations of 40-50 Å between compact and extended conformations. Notably, the intrinsic dynamics of PR65 facilitates complexation with the catalytic subunit and is retained in the PP2A complex enabling PR65 to engage the two domains of the catalytic subunit and provide the mechanical framework for enzymatic activity, with support from the regulatory subunit. In particular, the intra-repeat coils at the C-terminal arm play an important role in allosterically mediating the collective dynamics of PP2A, pointing to target sites for modulating PR65 function.
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Affiliation(s)
- Burak T Kaynak
- Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA; Computational Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Zakaria L Dahmani
- Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Pemra Doruker
- Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Anupam Banerjee
- Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA; Laufer Center for Physical and Quantitative Biology, and Department of Biochemistry and Cell Biology, School of Medicine, Stony Brook University, Stony Brook, NY 11794, USA
| | - Shang-Hua Yang
- Department of Electrical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Reuven Gordon
- Department of Electrical and Computer Engineering, University of Victoria, Victoria, BC V8P 5C2, Canada
| | - Laura S Itzhaki
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
| | - Ivet Bahar
- Laufer Center for Physical and Quantitative Biology, and Department of Biochemistry and Cell Biology, School of Medicine, Stony Brook University, Stony Brook, NY 11794, USA.
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4
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Hughes MD, Cussons S, Mahmoudi N, Brockwell DJ, Dougan L. Tuning Protein Hydrogel Mechanics through Modulation of Nanoscale Unfolding and Entanglement in Postgelation Relaxation. ACS NANO 2022; 16:10667-10678. [PMID: 35731007 PMCID: PMC9331141 DOI: 10.1021/acsnano.2c02369] [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] [Indexed: 05/20/2023]
Abstract
Globular folded proteins are versatile nanoscale building blocks to create biomaterials with mechanical robustness and inherent biological functionality due to their specific and well-defined folded structures. Modulating the nanoscale unfolding of protein building blocks during network formation (in situ protein unfolding) provides potent opportunities to control the protein network structure and mechanics. Here, we control protein unfolding during the formation of hydrogels constructed from chemically cross-linked maltose binding protein using ligand binding and the addition of cosolutes to modulate protein kinetic and thermodynamic stability. Bulk shear rheology characterizes the storage moduli of the bound and unbound protein hydrogels and reveals a correlation between network rigidity, characterized as an increase in the storage modulus, and protein thermodynamic stability. Furthermore, analysis of the network relaxation behavior identifies a crossover from an unfolding dominated regime to an entanglement dominated regime. Control of in situ protein unfolding and entanglement provides an important route to finely tune the architecture, mechanics, and dynamic relaxation of protein hydrogels. Such predictive control will be advantageous for future smart biomaterials for applications which require responsive and dynamic modulation of mechanical properties and biological function.
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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 LS2 9JT, U.K.
| | - Sophie Cussons
- Astbury Centre
for Structural Molecular Biology, University
of Leeds, Leeds LS2 9JT, U.K.
- School of
Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, U.K.
| | - Najet Mahmoudi
- ISIS
Neutron
and Muon Spallation Source, STFC Rutherford
Appleton Laboratory, Oxfordshire OX11 0QX, U.K.
| | - David J. Brockwell
- Astbury Centre
for Structural Molecular Biology, University
of Leeds, Leeds LS2 9JT, U.K.
- School of
Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, U.K.
| | - Lorna Dougan
- School of
Physics and Astronomy, Faculty of Engineering and Physical Sciences, 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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5
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Chetrit E, Sharma S, Maayan U, Pelah MG, Klausner Z, Popa I, Berkovich R. Nonexponential kinetics in captured in sequential unfolding of polyproteins over a range of loads. Curr Res Struct Biol 2022; 4:106-117. [PMID: 35540955 PMCID: PMC9079174 DOI: 10.1016/j.crstbi.2022.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 04/15/2022] [Accepted: 04/19/2022] [Indexed: 11/08/2022] Open
Abstract
While performing under mechanical loads in vivo, polyproteins are vitally involved in cellular mechanisms such as regulation of tissue elasticity and mechano-transduction by unfolding their comprising domains and extending them. It is widely thought that the process of sequential unfolding of polyproteins follows an exponential kinetics as the individual unfolding events exhibit identical and identically distributed (iid) Poisson behavior. However, it was shown that under high loads, the sequential unfolding kinetics displays nonexponential kinetics that alludes to aging by a subdiffusion process. Statistical order analysis of this kinetics indicated that the individual unfolding events are not iid, and cannot be defined as a Poisson (memoryless) process. Based on numerical simulations it was argued that this behavior becomes less pronounced with lowering the load, therefore it is to be expected that polyproteins unfolding under lower forces will follow a Poisson behavior. This expectation serves as the motivation of the current study, in which we investigate the effect of force lowering on the unfolding kinetics of Poly-L8 under varying loads, specifically high (150, 100 pN) and moderate-low (45, 30, 20 pN) forces. We found that a hierarchy among the unfolding events still exists even under low loads, again resulting in nonexponential behavior. We observe that analyzing the dwell-time distributions with stretched-exponentials and power laws give rise to different phenomenological trends. Using statistical order analysis, we demonstrated that even under the lowest load, the sequential unfolding cannot be considered as iid, in accord with the power law distribution. Additional free energy analysis revealed the contribution of the unfolded segments elasticity that scales with the force on the overall one-dimensional contour of the energy landscape, but more importantly, it discloses the hierarchy within the activation barriers during sequential unfolding that account for the observed nonexponentiality. Poly-L8 unfolding shows nonexponential kinetics at forces ranging from 150 to 20 pN. Different phenomenological trends are observed for the dwell-time distributions. The unfolding events were shown to be dependent and not identically distributed. Free energy analysis reveals elastic impact and hierarchy in the unfolding barriers.
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6
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Ferenczy GG, Kellermayer M. Contribution of Hydrophobic Interactions to Protein Mechanical Stability. Comput Struct Biotechnol J 2022; 20:1946-1956. [PMID: 35521554 PMCID: PMC9062142 DOI: 10.1016/j.csbj.2022.04.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Revised: 04/07/2022] [Accepted: 04/17/2022] [Indexed: 11/26/2022] Open
Abstract
The role of hydrophobic and polar interactions in providing thermodynamic stability to folded proteins has been intensively studied, but the relative contribution of these interactions to the mechanical stability is less explored. We used steered molecular dynamics simulations with constant-velocity pulling to generate force-extension curves of selected protein domains and monitor hydrophobic surface unravelling upon extension. Hydrophobic contribution was found to vary between one fifth and one third of the total force while the rest of the contribution is attributed primarily to hydrogen bonds. Moreover, hydrophobic force peaks were shifted towards larger protein extensions with respect to the force peaks attributed to hydrogen bonds. The higher importance of hydrogen bonds compared to hydrophobic interactions in providing mechanical resistance is in contrast with the relative importance of the hydrophobic interactions in providing thermodynamic stability of proteins. The different contributions of these interactions to the mechanical stability are explained by the steeper free energy dependence of hydrogen bonds compared to hydrophobic interactions on the relative positions of interacting atoms. Comparative analyses for several protein domains revealed that the variation of hydrophobic forces is modest, while the contribution of hydrogen bonds to the force peaks becomes increasingly important for mechanically resistant protein domains.
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7
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Santos MS, Liu H, Schittny V, Vanella R, Nash MA. Correlating single-molecule rupture mechanics with cell population adhesion by yeast display. BIOPHYSICAL REPORTS 2022; 2:None. [PMID: 35284851 PMCID: PMC8904261 DOI: 10.1016/j.bpr.2021.100035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 11/22/2021] [Indexed: 11/20/2022]
Affiliation(s)
- Mariana Sá Santos
- Institute for Physical Chemistry, Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland
- Systems Biology PhD program, Life Science Zurich Graduate School, Zurich, Switzerland
| | - Haipei Liu
- Institute for Physical Chemistry, Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland
| | - Valentin Schittny
- Institute for Physical Chemistry, Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland
| | - Rosario Vanella
- Institute for Physical Chemistry, Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland
| | - Michael A. Nash
- Institute for Physical Chemistry, Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland
- Corresponding author
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8
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Stannard A, Mora M, Beedle AE, Castro-López M, Board S, Garcia-Manyes S. Molecular Fluctuations as a Ruler of Force-Induced Protein Conformations. NANO LETTERS 2021; 21:2953-2961. [PMID: 33765390 PMCID: PMC7610714 DOI: 10.1021/acs.nanolett.1c00051] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Molecular fluctuations directly reflect the underlying energy landscape. Variance analysis examines protein dynamics in several biochemistry-driven approaches, yet measurement of probe-independent fluctuations in proteins exposed to mechanical forces remains only accessible through steered molecular dynamics simulations. Using single molecule magnetic tweezers, here we conduct variance analysis to show that individual unfolding and refolding transitions occurring in dynamic equilibrium in a single protein under force are hallmarked by a change in the protein's end-to-end fluctuations, revealing a change in protein stiffness. By unfolding and refolding three structurally distinct proteins under a wide range of constant forces, we demonstrate that the associated change in protein compliance to reach force-induced thermodynamically stable states scales with the protein's contour length increment, in agreement with the sequence-independent freely jointed chain model of polymer physics. Our findings will help elucidate the conformational dynamics of proteins exposed to mechanical force at high resolution which are of central importance in mechanosensing and mechanotransduction.
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Affiliation(s)
- Andrew Stannard
- Department of Physics, Randall Centre for Cell and Molecular Biophysics and London Centre for Nanotechnology, King’s College London, Strand, WC2R 2LS London, United Kingdom
| | - Marc Mora
- Department of Physics, Randall Centre for Cell and Molecular Biophysics and London Centre for Nanotechnology, King’s College London, Strand, WC2R 2LS London, United Kingdom
| | - Amy E.M. Beedle
- Department of Physics, Randall Centre for Cell and Molecular Biophysics and London Centre for Nanotechnology, King’s College London, Strand, WC2R 2LS London, United Kingdom
| | - Marta Castro-López
- Department of Physics, Randall Centre for Cell and Molecular Biophysics and London Centre for Nanotechnology, King’s College London, Strand, WC2R 2LS London, United Kingdom
| | - Stephanie Board
- Department of Physics, Randall Centre for Cell and Molecular Biophysics and London Centre for Nanotechnology, King’s College London, Strand, WC2R 2LS London, United Kingdom
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, London, UK
| | - Sergi Garcia-Manyes
- Department of Physics, Randall Centre for Cell and Molecular Biophysics and London Centre for Nanotechnology, King’s College London, Strand, WC2R 2LS London, United Kingdom
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, London, UK
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9
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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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10
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Evans SE, Harrington T, Rodriguez Rivero MC, Rognin E, Tuladhar T, Daly R. 2D and 3D inkjet printing of biopharmaceuticals - A review of trends and future perspectives in research and manufacturing. Int J Pharm 2021; 599:120443. [PMID: 33675921 DOI: 10.1016/j.ijpharm.2021.120443] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 02/24/2021] [Accepted: 02/25/2021] [Indexed: 12/13/2022]
Abstract
There is an ongoing global shift in pharmaceutical business models from small molecule drugs to biologics. This increase in complexity is in response to advancements in our diagnoses and understanding of diseases. With the more targeted approach coupled with its inherently more costly development and manufacturing, 2D and 3D printing are being explored as suitable techniques to deliver more personalised and affordable routes to drug discovery and manufacturing. In this review, we explore first the business context underlying this shift to biopharmaceuticals and provide an update on the latest work exploring discovery and pharmaceutics. We then draw on multiple disciplines to help reveal the shared challenges facing researchers and firms aiming to develop biopharmaceuticals, specifically when using the most commonly explored manufacturing routes of drop-on-demand inkjet printing and pneumatic extrusion. This includes separating out how to consider mechanical and chemical influences during manufacturing, the role of the chosen hardware and the challenges of aqueous formulation based on similar challenges being faced by the printing industry. Together, this provides a review of existing work and guidance for researchers and industry to help with the de-risking and rapid development of future biopharmaceutical products.
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Affiliation(s)
| | | | | | - Etienne Rognin
- Institute for Manufacturing, Department of Engineering, University of Cambridge (UK), UK
| | | | - Ronan Daly
- Institute for Manufacturing, Department of Engineering, University of Cambridge (UK), UK.
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11
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Yang B, Liu H, Liu Z, Doenen R, Nash MA. Influence of Fluorination on Single-Molecule Unfolding and Rupture Pathways of a Mechanostable Protein Adhesion Complex. NANO LETTERS 2020; 20:8940-8950. [PMID: 33191756 PMCID: PMC7729889 DOI: 10.1021/acs.nanolett.0c04178] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/08/2020] [Indexed: 05/25/2023]
Abstract
We investigated the influence of fluorination on unfolding and unbinding reaction pathways of a mechanostable protein complex comprising the tandem dyad XModule-Dockerin bound to Cohesin. Using single-molecule atomic force spectroscopy, we mapped the energy landscapes governing the unfolding and unbinding reactions. We then used sense codon suppression to substitute trifluoroleucine in place of canonical leucine globally in XMod-Doc. Although TFL substitution thermally destabilized XMod-Doc, it had little effect on XMod-Doc:Coh binding affinity at equilibrium. When we mechanically dissociated global TFL-substituted XMod-Doc from Coh, we observed the emergence of a new unbinding pathway with a lower energy barrier. Counterintuitively, when fluorination was restricted to Doc, we observed mechano-stabilization of the non-fluorinated neighboring XMod domain. This suggests that intramolecular deformation is modulated by fluorination and highlights the differences between equilibrium thermostability and non-equilibrium mechanostability. Future work is poised to investigate fluorination as a means to modulate mechanical properties of synthetic proteins and hydrogels.
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Affiliation(s)
- Byeongseon Yang
- Department
of Chemistry, University of Basel, 4058 Basel, Switzerland
- Department
of Biosystems Science and Engineering, ETH
Zurich, 4058 Basel, Switzerland
| | - Haipei Liu
- Department
of Chemistry, University of Basel, 4058 Basel, Switzerland
- Department
of Biosystems Science and Engineering, ETH
Zurich, 4058 Basel, Switzerland
| | - Zhaowei Liu
- Department
of Chemistry, University of Basel, 4058 Basel, Switzerland
- Department
of Biosystems Science and Engineering, ETH
Zurich, 4058 Basel, Switzerland
| | - Regina Doenen
- Department
of Chemistry, University of Basel, 4058 Basel, Switzerland
- Department
of Biosystems Science and Engineering, ETH
Zurich, 4058 Basel, Switzerland
| | - Michael A. Nash
- Department
of Chemistry, University of Basel, 4058 Basel, Switzerland
- Department
of Biosystems Science and Engineering, ETH
Zurich, 4058 Basel, Switzerland
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12
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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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13
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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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14
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Behrens HM, Lowe ED, Gault J, Housden NG, Kaminska R, Weber TM, Thompson CMA, Mislin GLA, Schalk IJ, Walker D, Robinson CV, Kleanthous C. Pyocin S5 Import into Pseudomonas aeruginosa Reveals a Generic Mode of Bacteriocin Transport. mBio 2020; 11:e03230-19. [PMID: 32156826 PMCID: PMC7064778 DOI: 10.1128/mbio.03230-19] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 01/28/2020] [Indexed: 11/20/2022] Open
Abstract
Pyocin S5 (PyoS5) is a potent protein bacteriocin that eradicates the human pathogen Pseudomonas aeruginosa in animal infection models, but its import mechanism is poorly understood. Here, using crystallography, biophysical and biochemical analyses, and live-cell imaging, we define the entry process of PyoS5 and reveal links to the transport mechanisms of other bacteriocins. In addition to its C-terminal pore-forming domain, elongated PyoS5 comprises two novel tandemly repeated kinked 3-helix bundle domains that structure-based alignments identify as key import domains in other pyocins. The central domain binds the lipid-bound common polysaccharide antigen, allowing the pyocin to accumulate on the cell surface. The N-terminal domain binds the ferric pyochelin transporter FptA while its associated disordered region binds the inner membrane protein TonB1, which together drive import of the bacteriocin across the outer membrane. Finally, we identify the minimal requirements for sensitizing Escherichia coli toward PyoS5, as well as other pyocins, and suggest that a generic pathway likely underpins the import of all TonB-dependent bacteriocins across the outer membrane of Gram-negative bacteria.IMPORTANCE Bacteriocins are toxic polypeptides made by bacteria to kill their competitors, making them interesting as potential antibiotics. Here, we reveal unsuspected commonalities in bacteriocin uptake pathways, through molecular and cellular dissection of the import pathway for the pore-forming bacteriocin pyocin S5 (PyoS5), which targets Pseudomonas aeruginosa In addition to its C-terminal pore-forming domain, PyoS5 is composed of two tandemly repeated helical domains that we also identify in other pyocins. Functional analyses demonstrate that they have distinct roles in the import process. One recognizes conserved sugars projected from the surface, while the other recognizes a specific outer membrane siderophore transporter, FptA, in the case of PyoS5. Through engineering of Escherichia coli cells, we show that pyocins can be readily repurposed to kill other species. This suggests basic ground rules for the outer membrane translocation step that likely apply to many bacteriocins targeting Gram-negative bacteria.
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Affiliation(s)
- Hannah M Behrens
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Edward D Lowe
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Joseph Gault
- Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom
| | - Nicholas G Housden
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Renata Kaminska
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - T Moritz Weber
- Institute of Bioorganic Chemistry, Heinrich Heine University Düsseldorf, Forschungszentrum Jülich, Jülich, Germany
| | - Catriona M A Thompson
- Institute of Infection, Immunity, and Inflammation, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Gaëtan L A Mislin
- UMR 7242, Biotechnologie et Signalisation Cellulaire, ESBS, Illkirch, France
| | - Isabelle J Schalk
- UMR 7242, Biotechnologie et Signalisation Cellulaire, ESBS, Illkirch, France
| | - Daniel Walker
- Institute of Infection, Immunity, and Inflammation, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Carol V Robinson
- Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom
| | - Colin Kleanthous
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
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15
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Churchill CDM, Healey MA, Preto J, Tuszynski JA, Woodside MT. Probing the Basis of α-Synuclein Aggregation by Comparing Simulations to Single-Molecule Experiments. Biophys J 2019; 117:1125-1135. [PMID: 31477241 DOI: 10.1016/j.bpj.2019.08.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 07/21/2019] [Accepted: 08/12/2019] [Indexed: 11/29/2022] Open
Abstract
Intrinsically disordered proteins often play an important role in protein aggregation. However, it is challenging to determine the structures and interactions that drive the early stages of aggregation because they are transient and obscured in a heterogeneous mixture of disordered states. Even computational methods are limited because the lack of ordered structure makes it difficult to ensure that the relevant conformations are sampled. We address these challenges by integrating atomistic simulations with high-resolution single-molecule measurements reported previously, using the measurements to help discern which parts of the disordered ensemble of structures in the simulations are most probable while using the simulations to identify residues and interactions that are important for oligomer stability. This approach was applied to α-synuclein, an intrinsically disordered protein that aggregates in the context of Parkinson's disease. We simulated single-molecule pulling experiments on dimers, the minimal oligomer, and compared them to force spectroscopy measurements. Force-extension curves were simulated starting from a set of 66 structures with substantial structured content selected from the ensemble of dimer structures generated at zero force via Monte Carlo simulations. The pattern of contour length changes as the structures unfolded through intermediate states was compared to the results from optical trapping measurements on the same dimer to discern likely structures occurring in the measurements. Simulated pulling curves were generally consistent with experimental data but with a larger number of transient intermediates. We identified an ensemble of β-rich dimer structures consistent with the experimental data from which dimer interfaces could be deduced. These results suggest specific druggable targets in the structural motifs of α-synuclein that may help prevent the earliest steps of oligomerization.
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Affiliation(s)
| | - Mark A Healey
- Department of Physics, University of Alberta, Edmonton, Alberta, Canada
| | - Jordane Preto
- Department of Physics, University of Alberta, Edmonton, Alberta, Canada
| | - Jack A Tuszynski
- Department of Physics, University of Alberta, Edmonton, Alberta, Canada; Department of Oncology, University of Alberta, Edmonton, Alberta, Canada.
| | - Michael T Woodside
- Department of Physics, University of Alberta, Edmonton, Alberta, Canada.
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16
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De-la-Torre P, Choudhary D, Araya-Secchi R, Narui Y, Sotomayor M. A Mechanically Weak Extracellular Membrane-Adjacent Domain Induces Dimerization of Protocadherin-15. Biophys J 2018; 115:2368-2385. [PMID: 30527337 PMCID: PMC6302040 DOI: 10.1016/j.bpj.2018.11.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 11/01/2018] [Accepted: 11/05/2018] [Indexed: 10/27/2022] Open
Abstract
The cadherin superfamily of proteins is defined by the presence of extracellular cadherin (EC) "repeats" that engage in protein-protein interactions to mediate cell-cell adhesion, cell signaling, and mechanotransduction. The extracellular domains of nonclassical cadherins often have a large number of EC repeats along with other subdomains of various folds. Protocadherin-15 (PCDH15), a protein component of the inner-ear tip link filament essential for mechanotransduction, has 11 EC repeats and a membrane adjacent domain (MAD12) of atypical fold. Here we report the crystal structure of a pig PCDH15 fragment including EC10, EC11, and MAD12 in a parallel dimeric arrangement. MAD12 has a unique molecular architecture and folds as a ferredoxin-like domain similar to that found in the nucleoporin protein Nup54. Analytical ultracentrifugation experiments along with size-exclusion chromatography coupled to multiangle laser light scattering and small-angle x-ray scattering corroborate the crystallographic dimer and show that MAD12 induces parallel dimerization of PCDH15 near its membrane insertion point. In addition, steered molecular dynamics simulations suggest that MAD12 is mechanically weak and may unfold before tip-link rupture. Sequence analyses and structural modeling predict the existence of similar domains in cadherin-23, protocadherin-24, and the "giant" FAT and CELSR cadherins, indicating that some of them may also exhibit MAD-induced parallel dimerization.
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Affiliation(s)
- Pedro De-la-Torre
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio
| | - Deepanshu Choudhary
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio
| | - Raul Araya-Secchi
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio; Structural Biophysics, Section for Neutron and X-ray Science, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Yoshie Narui
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio
| | - Marcos Sotomayor
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio.
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17
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Bhattacharya S, Ainavarapu SRK. Mechanical Softening of a Small Ubiquitin-Related Modifier Protein Due to Temperature Induced Flexibility at the Core. J Phys Chem B 2018; 122:9128-9136. [PMID: 30204456 DOI: 10.1021/acs.jpcb.8b06844] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Despite the growing interest in the thermal softening of proteins, the mechanistic details of it are far from understood. β-Grasp proteins have globular shape with compact structure and they are mechanically resilient. The β-clamp or mechanical clamp in them formed by the interactions between the terminal β-strands is generally associated with the protein mechanical resistance. Although previous studies showed that temperature can perturb the protein mechanical stability, the structural changes leading to the lowered mechanical resistance are not known. Here, we investigated the temperature dependent mechanical stability of small ubiquitin-related modifier 2 (SUMO2) using single-molecule force spectroscopy (SMFS) and the corresponding conformational changes using ensemble experiments. SMFS studies on the polyprotein of SUMO2 estimate a decrease in the spring constant of the protein from 4.50 to 1.35 N/m upon increasing the temperature from 5 to 45 °C. Interestingly, near-UV circular dichroism spectroscopy reveals a decrease in tertiary structure content while the overall secondary structure of the protein remains unchanged. Steady-state fluorescence and quenching studies on SUMO2 with a tryptophan mutation at the core (F60W) show that the nonpolar environment of the tryptophan is unchanged and the protein core is inaccessible to the bulk solvent, in the same temperature range. We attribute the thermal softening observed in atomic force microscopy (AFM) experiments to the reduction in tertiary structure of SUMO2. Our results provide evidence for the importance of the intramolecular interactions at the protein core along with the β-clamp or mechanical clamp in providing the mechanical resistance as well as in modulating the protein stiffness.
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Affiliation(s)
- Shrabasti Bhattacharya
- 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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18
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Switching of the folding-energy landscape governs the allosteric activation of protein kinase A. Proc Natl Acad Sci U S A 2018; 115:E7478-E7485. [PMID: 30038016 DOI: 10.1073/pnas.1802510115] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Protein kinases are dynamic molecular switches that sample multiple conformational states. The regulatory subunit of PKA harbors two cAMP-binding domains [cyclic nucleotide-binding (CNB) domains] that oscillate between inactive and active conformations dependent on cAMP binding. The cooperative binding of cAMP to the CNB domains activates an allosteric interaction network that enables PKA to progress from the inactive to active conformation, unleashing the activity of the catalytic subunit. Despite its importance in the regulation of many biological processes, the molecular mechanism responsible for the observed cooperativity during the activation of PKA remains unclear. Here, we use optical tweezers to probe the folding cooperativity and energetics of domain communication between the cAMP-binding domains in the apo state and bound to the catalytic subunit. Our study provides direct evidence of a switch in the folding-energy landscape of the two CNB domains from energetically independent in the apo state to highly cooperative and energetically coupled in the presence of the catalytic subunit. Moreover, we show that destabilizing mutational effects in one CNB domain efficiently propagate to the other and decrease the folding cooperativity between them. Taken together, our results provide a thermodynamic foundation for the conformational plasticity that enables protein kinases to adapt and respond to signaling molecules.
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19
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Mallik S, Kundu S. Topology and Oligomerization of Mono- and Oligomeric Proteins Regulate Their Half-Lives in the Cell. Structure 2018; 26:869-878.e3. [DOI: 10.1016/j.str.2018.04.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 03/07/2018] [Accepted: 04/25/2018] [Indexed: 01/28/2023]
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20
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Doherty CPA, Young LM, Karamanos TK, Smith HI, Jackson MP, Radford SE, Brockwell DJ. A peptide-display protein scaffold to facilitate single molecule force studies of aggregation-prone peptides. Protein Sci 2018; 27:1205-1217. [PMID: 29417650 PMCID: PMC6032367 DOI: 10.1002/pro.3386] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 02/05/2018] [Accepted: 02/05/2018] [Indexed: 01/12/2023]
Abstract
Protein aggregation is linked with the onset of several neurodegenerative disorders, including Parkinson's disease (PD), which is associated with the aggregation of α‐synuclein (αSyn). The structural mechanistic details of protein aggregation, including the nature of the earliest protein–protein interactions, remain elusive. In this study, we have used single molecule force spectroscopy (SMFS) to probe the first dimerization events of the central aggregation‐prone region of αSyn (residues 71–82) that may initiate aggregation. This region has been shown to be necessary for the aggregation of full length αSyn and is capable of forming amyloid fibrils in isolation. We demonstrate that the interaction of αSyn71‐82 peptides can be studied using SMFS when inserted into a loop of protein L, a mechanically strong and soluble scaffold protein that acts as a display system for SMFS studies. The corresponding fragment of the homolog protein γ‐synuclein (γSyn), which has a lower aggregation propensity, has also been studied here. The results from SMFS, together with native mass spectrometry and aggregation assays, demonstrate that the dimerization propensity of γSyn71‐82 is lower than that of αSyn71‐82, but that a mixed αSyn71‐82: γSyn71‐82 dimer forms with a similar propensity to the αSyn71‐82 homodimer, slowing amyloid formation. This work demonstrates the utility of a novel display method for SMFS studies of aggregation‐prone peptides, which would otherwise be difficult to study.
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Affiliation(s)
- Ciaran P A Doherty
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom.,School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Lydia M Young
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom.,School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Theodoros K Karamanos
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom.,School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Hugh I Smith
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom.,School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Matthew P Jackson
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom.,School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom.,School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - David J Brockwell
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom.,School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
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21
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Comparative mechanical unfolding studies of spectrin domains R15, R16 and R17. J Struct Biol 2017; 201:162-170. [PMID: 29221897 DOI: 10.1016/j.jsb.2017.12.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 11/08/2017] [Accepted: 12/04/2017] [Indexed: 11/20/2022]
Abstract
Spectrins belong to repetitive three-helix bundle proteins that have vital functions in multicellular organisms and are of potential value in nanotechnology. To reveal the unique physical features of repeat proteins we have studied the structural and mechanical properties of three repeats of chicken brain α-spectrin (R15, R16 and R17) at the atomic level under stretching at constant velocities (0.01, 0.05 and 0.1 Å·ps-1) and constant forces (700 and 900 pN) using molecular dynamics (MD) simulations at T = 300 K. 114 independent MD simulations were performed and their analysis has been done. Despite structural similarity of these domains we have found that R15 is less mechanically stable than R16, which is less stable than R17. This result is in agreement with the thermal unfolding rates. Moreover, we have observed the relationship between mechanical stability, flexibility of the domains and the number of aromatic residues involved in aromatic clusters.
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22
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Chwastyk M, Vera AM, Galera-Prat A, Gunnoo M, Thompson D, Carrión-Vázquez M, Cieplak M. Non-local effects of point mutations on the stability of a protein module. J Chem Phys 2017; 147:105101. [DOI: 10.1063/1.4999703] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Mateusz Chwastyk
- Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, PL-02668 Warsaw, Poland
| | - Andrés M. Vera
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, (CSIC), Ave. Doctor Arce, 37, 28002 Madrid, Spain
| | - Albert Galera-Prat
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, (CSIC), Ave. Doctor Arce, 37, 28002 Madrid, Spain
| | - Melissabye Gunnoo
- Department of Physics, Bernal Institute, University of Limerick, Limerick V94 T9PX, Ireland
| | - Damien Thompson
- Department of Physics, Bernal Institute, University of Limerick, Limerick V94 T9PX, Ireland
| | - Mariano Carrión-Vázquez
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, (CSIC), Ave. Doctor Arce, 37, 28002 Madrid, Spain
| | - Marek Cieplak
- Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, PL-02668 Warsaw, Poland
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23
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Sun Y, Di W, Li Y, Huang W, Wang X, Qin M, Wang W, Cao Y. Mg2+-Dependent High Mechanical Anisotropy of Three-Way-Junction pRNA as Revealed by Single-Molecule Force Spectroscopy. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201704113] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Yang Sun
- Collaborative Innovation Center of Advanced Microstructures; National Laboratory of Solid State Microstructure; Department of Physics; Nanjing University; 22 Hankou Road Nanjing Jiang Su 210093 P.R. China
| | - Weishuai Di
- Collaborative Innovation Center of Advanced Microstructures; National Laboratory of Solid State Microstructure; Department of Physics; Nanjing University; 22 Hankou Road Nanjing Jiang Su 210093 P.R. China
| | - Yiran Li
- Collaborative Innovation Center of Advanced Microstructures; National Laboratory of Solid State Microstructure; Department of Physics; Nanjing University; 22 Hankou Road Nanjing Jiang Su 210093 P.R. China
| | - Wenmao Huang
- Collaborative Innovation Center of Advanced Microstructures; National Laboratory of Solid State Microstructure; Department of Physics; Nanjing University; 22 Hankou Road Nanjing Jiang Su 210093 P.R. China
| | - Xin Wang
- Collaborative Innovation Center of Advanced Microstructures; National Laboratory of Solid State Microstructure; Department of Physics; Nanjing University; 22 Hankou Road Nanjing Jiang Su 210093 P.R. China
| | - Meng Qin
- Collaborative Innovation Center of Advanced Microstructures; National Laboratory of Solid State Microstructure; Department of Physics; Nanjing University; 22 Hankou Road Nanjing Jiang Su 210093 P.R. China
| | - Wei Wang
- Collaborative Innovation Center of Advanced Microstructures; National Laboratory of Solid State Microstructure; Department of Physics; Nanjing University; 22 Hankou Road Nanjing Jiang Su 210093 P.R. China
| | - Yi Cao
- Collaborative Innovation Center of Advanced Microstructures; National Laboratory of Solid State Microstructure; Department of Physics; Nanjing University; 22 Hankou Road Nanjing Jiang Su 210093 P.R. China
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24
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Sun Y, Di W, Li Y, Huang W, Wang X, Qin M, Wang W, Cao Y. Mg 2+ -Dependent High Mechanical Anisotropy of Three-Way-Junction pRNA as Revealed by Single-Molecule Force Spectroscopy. Angew Chem Int Ed Engl 2017. [PMID: 28631866 DOI: 10.1002/anie.201704113] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Mechanical anisotropy is ubiquitous in biological tissues but is hard to reproduce in synthetic biomaterials. Developing molecular building blocks with anisotropic mechanical response is the key towards engineering anisotropic biomaterials. The three-way-junction (3WJ) pRNA, derived from ϕ29 DNA packaging motor, shows strong mechanical anisotropy upon Mg2+ binding. In the absence of Mg2+ , 3WJ-pRNA is mechanically weak without noticeable mechanical anisotropy. In the presence of Mg2+ , the unfolding forces can differ by more than 4-fold along different pulling directions, ranging from about 47 pN to about 219 pN. Mechanical anisotropy of 3WJ-pRNA stems from pulling direction dependent cooperativity for the rupture of two Mg2+ binding sites, which is a novel mechanism for the mechanical anisotropy of biomacromolecules. It is anticipated that 3WJ-pRNA can be used as a key element for the construction of biomaterials with controllable mechanical anisotropy.
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Affiliation(s)
- Yang Sun
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, 22 Hankou Road, Nanjing, Jiang Su, 210093, P.R. China
| | - Weishuai Di
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, 22 Hankou Road, Nanjing, Jiang Su, 210093, P.R. China
| | - Yiran Li
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, 22 Hankou Road, Nanjing, Jiang Su, 210093, P.R. China
| | - Wenmao Huang
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, 22 Hankou Road, Nanjing, Jiang Su, 210093, P.R. China
| | - Xin Wang
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, 22 Hankou Road, Nanjing, Jiang Su, 210093, P.R. China
| | - Meng Qin
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, 22 Hankou Road, Nanjing, Jiang Su, 210093, P.R. China
| | - Wei Wang
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, 22 Hankou Road, Nanjing, Jiang Su, 210093, P.R. China
| | - Yi Cao
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, 22 Hankou Road, Nanjing, Jiang Su, 210093, P.R. China
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25
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Unusually high mechanical stability of bacterial adhesin extender domains having calcium clamps. PLoS One 2017; 12:e0174682. [PMID: 28376122 PMCID: PMC5380327 DOI: 10.1371/journal.pone.0174682] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 03/12/2017] [Indexed: 01/07/2023] Open
Abstract
To gain insight into the relationship between protein structure and mechanical stability, single molecule force spectroscopy experiments on proteins with diverse structure and topology are needed. Here, we measured the mechanical stability of extender domains of two bacterial adhesins MpAFP and MhLap, in an atomic force microscope. We find that both proteins are remarkably stable to pulling forces between their N- and C- terminal ends. At a pulling speed of 1 μm/s, the MpAFP extender domain fails at an unfolding force Fu = 348 ± 37 pN and MhLap at Fu = 306 ± 51 pN in buffer with 10 mM Ca2+. These forces place both extender domains well above the mechanical stability of many other β-sandwich domains in mechanostable proteins. We propose that the increased stability of MpAFP and MhLap is due to a combination of both hydrogen bonding between parallel terminal strands and intra-molecular coordination of calcium ions.
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26
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da Silva M, Lenton S, Hughes M, Brockwell DJ, Dougan L. Assessing the Potential of Folded Globular Polyproteins As Hydrogel Building Blocks. Biomacromolecules 2017; 18:636-646. [PMID: 28006103 PMCID: PMC5348097 DOI: 10.1021/acs.biomac.6b01877] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 12/21/2016] [Indexed: 01/14/2023]
Abstract
The native states of proteins generally have stable well-defined folded structures endowing these biomolecules with specific functionality and molecular recognition abilities. Here we explore the potential of using folded globular polyproteins as building blocks for hydrogels. Photochemically cross-linked hydrogels were produced from polyproteins containing either five domains of I27 ((I27)5), protein L ((pL)5), or a 1:1 blend of these proteins. SAXS analysis showed that (I27)5 exists as a single rod-like structure, while (pL)5 shows signatures of self-aggregation in solution. SANS measurements showed that both polyprotein hydrogels have a similar nanoscopic structure, with protein L hydrogels being formed from smaller and more compact clusters. The polyprotein hydrogels showed small energy dissipation in a load/unload cycle, which significantly increased when the hydrogels were formed in the unfolded state. This study demonstrates the use of folded proteins as building blocks in hydrogels, and highlights the potential versatility that can be offered in tuning the mechanical, structural, and functional properties of polyproteins.
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Affiliation(s)
- Marcelo
A. da Silva
- School of Physics and Astronomy and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Samuel Lenton
- School of Physics and Astronomy and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Matthew Hughes
- School of Physics and Astronomy and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - David J. Brockwell
- School of Physics and Astronomy and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Lorna Dougan
- School of Physics and Astronomy and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
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27
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He C, Li H. Staphylokinase Displays Surprisingly Low Mechanical Stability. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:1077-1083. [PMID: 28040904 DOI: 10.1021/acs.langmuir.6b04425] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Single-molecule force spectroscopy (SMFS) and molecular dynamics (MD) simulations have revealed that shear topology is an important structural feature for mechanically stable proteins. Proteins containing a β-grasp fold display the typical shear topology and are generally of significant mechanical stability. In an effort to experimentally identify mechanically strong proteins using single-molecule atomic force microscopy, we found that staphylokinase (SAK), which has a typical β-grasp fold and was predicted to be mechanically stable in coarse-grained MD simulations, displays surprisingly low mechanical stability. At a pulling speed of 400 nm/s, SAK unfolds at ∼60 pN, making it the mechanically weakest protein among the β-grasp fold proteins that have been characterized experimentally. In contrast, its structural homologous protein streptokinase β domain displays significant mechanical stability under the same experimental condition. Our results showed that the large malleability of native-state SAK is largely responsible for its low mechanical stability. The molecular origin of this large malleability of SAK remains unknown. Our results reveal a hidden complexity in protein mechanics and call for a detailed investigation into the molecular determinants of the protein mechanical malleability.
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Affiliation(s)
- Chengzhi He
- Department of Chemistry, University of British Columbia , Vancouver, BC V6T 1Z1, Canada
| | - Hongbin Li
- Department of Chemistry, University of British Columbia , Vancouver, BC V6T 1Z1, Canada
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28
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Lei H, Guo Y, Hu X, Hu C, Hu X, Li H. Reversible Unfolding and Folding of the Metalloprotein Ferredoxin Revealed by Single-Molecule Atomic Force Microscopy. J Am Chem Soc 2017; 139:1538-1544. [DOI: 10.1021/jacs.6b11371] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hai Lei
- State
Key Laboratory of Precision Measurements Technology and Instruments,
School of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, People’s Republic of China
- Department
of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Yabin Guo
- Department
of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Xiaodong Hu
- State
Key Laboratory of Precision Measurements Technology and Instruments,
School of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, People’s Republic of China
| | - Chunguang Hu
- State
Key Laboratory of Precision Measurements Technology and Instruments,
School of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, People’s Republic of China
| | - Xiaotang Hu
- State
Key Laboratory of Precision Measurements Technology and Instruments,
School of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, People’s Republic of China
| | - Hongbin Li
- State
Key Laboratory of Precision Measurements Technology and Instruments,
School of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, People’s Republic of China
- Department
of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
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29
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Stauch T, Dreuw A. Advances in Quantum Mechanochemistry: Electronic Structure Methods and Force Analysis. Chem Rev 2016; 116:14137-14180. [PMID: 27767298 DOI: 10.1021/acs.chemrev.6b00458] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In quantum mechanochemistry, quantum chemical methods are used to describe molecules under the influence of an external force. The calculation of geometries, energies, transition states, reaction rates, and spectroscopic properties of molecules on the force-modified potential energy surfaces is the key to gain an in-depth understanding of mechanochemical processes at the molecular level. In this review, we present recent advances in the field of quantum mechanochemistry and introduce the quantum chemical methods used to calculate the properties of molecules under an external force. We place special emphasis on quantum chemical force analysis tools, which can be used to identify the mechanochemically relevant degrees of freedom in a deformed molecule, and spotlight selected applications of quantum mechanochemical methods to point out their synergistic relationship with experiments.
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Affiliation(s)
- Tim Stauch
- Interdisciplinary Center for Scientific Computing , Im Neuenheimer Feld 205, 69120 Heidelberg, Germany
| | - Andreas Dreuw
- Interdisciplinary Center for Scientific Computing , Im Neuenheimer Feld 205, 69120 Heidelberg, Germany
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30
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Wołek K, Gómez-Sicilia À, Cieplak M. Determination of contact maps in proteins: A combination of structural and chemical approaches. J Chem Phys 2016; 143:243105. [PMID: 26723590 DOI: 10.1063/1.4929599] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Contact map selection is a crucial step in structure-based molecular dynamics modelling of proteins. The map can be determined in many different ways. We focus on the methods in which residues are represented as clusters of effective spheres. One contact map, denoted as overlap (OV), is based on the overlap of such spheres. Another contact map, named Contacts of Structural Units (CSU), involves the geometry in a different way and, in addition, brings chemical considerations into account. We develop a variant of the CSU approach in which we also incorporate Coulombic effects such as formation of the ionic bridges and destabilization of possible links through repulsion. In this way, the most essential and well defined contacts are identified. The resulting residue-residue contact map, dubbed repulsive CSU (rCSU), is more sound in its physico-chemical justification than CSU. It also provides a clear prescription for validity of an inter-residual contact: the number of attractive atomic contacts should be larger than the number of repulsive ones - a feature that is not present in CSU. However, both of these maps do not correlate well with the experimental data on protein stretching. Thus, we propose to use rCSU together with the OV map. We find that the combined map, denoted as OV+rCSU, performs better than OV. In most situations, OV and OV+rCSU yield comparable folding properties but for some proteins rCSU provides contacts which improve folding in a substantial way. We discuss the likely residue-specificity of the rCSU contacts. Finally, we make comparisons to the recently proposed shadow contact map, which is derived from different principles.
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Affiliation(s)
- Karol Wołek
- Institute of Physics, Polish Academy of Science, Al. Lotników 32/46, 02-668 Warsaw, Poland
| | - Àngel Gómez-Sicilia
- Instituto Cajal, Consejo Superior de Investigaciones Cientificas (CSIC), Av. Doctor Arce, 37, 28002 Madrid, Spain
| | - Marek Cieplak
- Institute of Physics, Polish Academy of Science, Al. Lotników 32/46, 02-668 Warsaw, Poland
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31
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Popa I, Rivas-Pardo JA, Eckels EC, Echelman DJ, Badilla CL, Valle-Orero J, Fernández JM. A HaloTag Anchored Ruler for Week-Long Studies of Protein Dynamics. J Am Chem Soc 2016; 138:10546-53. [PMID: 27409974 PMCID: PMC5510598 DOI: 10.1021/jacs.6b05429] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Under physiological conditions, protein oxidation and misfolding occur with very low probability and on long times scales. Single-molecule techniques provide the ability to distinguish between properly folded and damaged proteins that are otherwise masked in ensemble measurements. However, at physiological conditions these rare events occur with a time constant of several hours, inaccessible to current single-molecule approaches. Here we present a magnetic-tweezers-based technique that allows, for the first time, the study of folding of single proteins during week-long experiments. This technique combines HaloTag anchoring, sub-micrometer positioning of magnets, and an active correction of the focal drift. Using this technique and protein L as a molecular template, we generate a magnet law by correlating the distance between the magnet and the measuring paramagnetic bead with unfolding/folding steps. We demonstrate that, using this magnet law, we can accurately measure the dynamics of proteins over a wide range of forces, with minimal dispersion from bead to bead. We also show that the force calibration remains invariant over week-long experiments applied to the same single proteins. The approach demonstrated in this Article opens new, exciting ways to examine proteins on the "human" time scale and establishes magnetic tweezers as a valuable technique to study low-probability events that occur during protein folding under force.
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Affiliation(s)
- Ionel Popa
- Department of Biological Sciences, Columbia University , 1212 Amsterdam Avenue, New York, New York 10027, United States
| | - Jaime Andrés Rivas-Pardo
- Department of Biological Sciences, Columbia University , 1212 Amsterdam Avenue, New York, New York 10027, United States
| | - Edward C Eckels
- Department of Biological Sciences, Columbia University , 1212 Amsterdam Avenue, New York, New York 10027, United States
| | - Daniel J Echelman
- Department of Biological Sciences, Columbia University , 1212 Amsterdam Avenue, New York, New York 10027, United States
| | - Carmen L Badilla
- Department of Biological Sciences, Columbia University , 1212 Amsterdam Avenue, New York, New York 10027, United States
| | - Jessica Valle-Orero
- Department of Biological Sciences, Columbia University , 1212 Amsterdam Avenue, New York, New York 10027, United States
| | - Julio M Fernández
- Department of Biological Sciences, Columbia University , 1212 Amsterdam Avenue, New York, New York 10027, United States
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32
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Hughes ML, Dougan L. The physics of pulling polyproteins: a review of single molecule force spectroscopy using the AFM to study protein unfolding. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:076601. [PMID: 27309041 DOI: 10.1088/0034-4885/79/7/076601] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
One of the most exciting developments in the field of biological physics in recent years is the ability to manipulate single molecules and probe their properties and function. Since its emergence over two decades ago, single molecule force spectroscopy has become a powerful tool to explore the response of biological molecules, including proteins, DNA, RNA and their complexes, to the application of an applied force. The force versus extension response of molecules can provide valuable insight into its mechanical stability, as well as details of the underlying energy landscape. In this review we will introduce the technique of single molecule force spectroscopy using the atomic force microscope (AFM), with particular focus on its application to study proteins. We will review the models which have been developed and employed to extract information from single molecule force spectroscopy experiments. Finally, we will end with a discussion of future directions in this field.
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Affiliation(s)
- Megan L Hughes
- School of Physics and Astronomy, University of Leeds, LS2 9JT, UK. Astbury Centre for Structural and Molecular Biology, University of Leeds, LS2 9JT, UK
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33
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Jagannathan B, Marqusee S. Protein folding and unfolding under force. Biopolymers 2016; 99:860-9. [PMID: 23784721 DOI: 10.1002/bip.22321] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 06/07/2013] [Indexed: 12/27/2022]
Abstract
The recent revolution in optics and instrumentation has enabled the study of protein folding using extremely low mechanical forces as the denaturant. This exciting development has led to the observation of the protein folding process at single molecule resolution and its response to mechanical force. Here, we describe the principles and experimental details of force spectroscopy on proteins, with a focus on the optical tweezers instrument. Several recent results will be discussed to highlight the importance of this technique in addressing a variety of questions in the protein folding field.
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Affiliation(s)
- Bharat Jagannathan
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA
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34
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Booth JJ, Shalashilin DV. Fully Atomistic Simulations of Protein Unfolding in Low Speed Atomic Force Microscope and Force Clamp Experiments with the Help of Boxed Molecular Dynamics. J Phys Chem B 2016; 120:700-8. [DOI: 10.1021/acs.jpcb.5b11519] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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35
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Kravats AN, Tonddast-Navaei S, Stan G. Coarse-Grained Simulations of Topology-Dependent Mechanisms of Protein Unfolding and Translocation Mediated by ClpY ATPase Nanomachines. PLoS Comput Biol 2016; 12:e1004675. [PMID: 26734937 PMCID: PMC4703411 DOI: 10.1371/journal.pcbi.1004675] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 11/25/2015] [Indexed: 01/30/2023] Open
Abstract
Clp ATPases are powerful ring shaped nanomachines which participate in the degradation pathway of the protein quality control system, coupling the energy from ATP hydrolysis to threading substrate proteins (SP) through their narrow central pore. Repetitive cycles of sequential intra-ring ATP hydrolysis events induce axial excursions of diaphragm-forming central pore loops that effect the application of mechanical forces onto SPs to promote unfolding and translocation. We perform Langevin dynamics simulations of a coarse-grained model of the ClpY ATPase-SP system to elucidate the molecular details of unfolding and translocation of an α/β model protein. We contrast this mechanism with our previous studies which used an all-α SP. We find conserved aspects of unfolding and translocation mechanisms by allosteric ClpY, including unfolding initiated at the tagged C-terminus and translocation via a power stroke mechanism. Topology-specific aspects include the time scales, the rate limiting steps in the degradation pathway, the effect of force directionality, and the translocase efficacy. Mechanisms of ClpY-assisted unfolding and translocation are distinct from those resulting from non-allosteric mechanical pulling. Bulk unfolding simulations, which mimic Atomic Force Microscopy-type pulling, reveal multiple unfolding pathways initiated at the C-terminus, N-terminus, or simultaneously from both termini. In a non-allosteric ClpY ATPase pore, mechanical pulling with constant velocity yields larger effective forces for SP unfolding, while pulling with constant force results in simultaneous unfolding and translocation. Cell survival is critically dependent on tightly regulated protein quality control, which includes chaperone-mediated folding and degradation. In the degradation pathway, AAA+ nanomachines, such as bacterial Clp proteases, use ATP-driven mechanisms to mechanically unfold, translocate, and destroy excess or defective proteins. Understanding these remodeling mechanisms is of central importance for deciphering the details of essential cellular processes. We perform coarse-grained computer simulations to extensively probe the effect of substrate protein topology on unfolding and translocation actions of the ClpY ATPase nanomachine. We find that, independent of SP topology, unfolding proceeds from the tagged C-terminus, which is engaged by the ATPase, and translocation involves coordinated steps. Topology-specific aspects include more complex unfolding and translocation pathways of the α/β SP compared with the all-α SP due to high stability of β-hairpins and interplay of tertiary contacts. In addition, directionality of the mechanical force applied by the Clp ATPase gives rise to distinct unfolding pathways.
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Affiliation(s)
- Andrea N. Kravats
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Sam Tonddast-Navaei
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - George Stan
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, United States of America
- * E-mail:
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36
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Hoffmann T, Tych KM, Crosskey T, Schiffrin B, Brockwell DJ, Dougan L. Rapid and Robust Polyprotein Production Facilitates Single-Molecule Mechanical Characterization of β-Barrel Assembly Machinery Polypeptide Transport Associated Domains. ACS NANO 2015; 9:8811-21. [PMID: 26284289 DOI: 10.1021/acsnano.5b01962] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Single-molecule force spectroscopy by atomic force microscopy exploits the use of multimeric protein constructs, namely, polyproteins, to decrease the impact of nonspecific interactions, to improve data accumulation, and to allow the accommodation of benchmarking reference domains within the construct. However, methods to generate such constructs are either time- and labor-intensive or lack control over the length or the domain sequence of the obtained construct. Here, we describe an approach that addresses both of these shortcomings that uses Gibson assembly (GA) to generate a defined recombinant polyprotein rapidly using linker sequences. To demonstrate the feasibility of this approach, we used GA to make a polyprotein composed of alternating domains of I27 and TmCsp, (I27-TmCsp)3-I27)(GA), and showed the mechanical fingerprint, mechanical strength, and pulling speed dependence are the same as an analogous polyprotein constructed using the classical approach. After this benchmarking, we exploited this approach to facilitiate the mechanical characterization of POTRA domain 2 of BamA from E. coli (EcPOTRA2) by assembling the polyprotein (I27-EcPOTRA2)3-I27(GA). We show that, as predicted from the α + β topology, EcPOTRA2 domains are mechanically robust over a wide range of pulling speeds. Furthermore, we identify a clear correlation between mechanical robustness and brittleness for a range of other α + β proteins that contain the structural feature of proximal terminal β-strands in parallel geometry. We thus demonstrate that the GA approach is a powerful tool, as it circumvents the usual time- and labor-intensive polyprotein production process and allows for rapid production of new constructs for single-molecule studies. As shown for EcPOTRA2, this approach allows the exploration of the mechanical properties of a greater number of proteins and their variants. This improves our understanding of the relationship between structure and mechanical strength, increasing our ability to design proteins with tailored mechanical properties.
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Affiliation(s)
- Toni Hoffmann
- School of Physics and Astronomy, ‡Astbury Centre for Structural and Molecular Biology, and §School of Molecular and Cellular Biology, University of Leeds , Leeds, LS2 9JT, U.K
| | - Katarzyna M Tych
- School of Physics and Astronomy, ‡Astbury Centre for Structural and Molecular Biology, and §School of Molecular and Cellular Biology, University of Leeds , Leeds, LS2 9JT, U.K
| | - Thomas Crosskey
- School of Physics and Astronomy, ‡Astbury Centre for Structural and Molecular Biology, and §School of Molecular and Cellular Biology, University of Leeds , Leeds, LS2 9JT, U.K
| | - Bob Schiffrin
- School of Physics and Astronomy, ‡Astbury Centre for Structural and Molecular Biology, and §School of Molecular and Cellular Biology, University of Leeds , Leeds, LS2 9JT, U.K
| | - David J Brockwell
- School of Physics and Astronomy, ‡Astbury Centre for Structural and Molecular Biology, and §School of Molecular and Cellular Biology, University of Leeds , Leeds, LS2 9JT, U.K
| | - Lorna Dougan
- School of Physics and Astronomy, ‡Astbury Centre for Structural and Molecular Biology, and §School of Molecular and Cellular Biology, University of Leeds , Leeds, LS2 9JT, U.K
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37
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Abstract
Zinc fingers are highly ubiquitous structural motifs that provide stability to proteins, thus contributing to their correct folding. Despite the high thermodynamic stability of the ZnCys4 centers, their kinetic properties display remarkable lability. Here, we use a combination of protein engineering with single molecule force spectroscopy atomic force microscopy (AFM) to uncover the surprising mechanical lability (∼90 pN) of the individual Zn-S bonds that form the two equivalent zinc finger motifs embedded in the structure of the multidomain DnaJ chaperone. Rational mutations within the zinc coordinating residues enable direct identification of the chemical determinants that regulate the interplay between zinc binding-requiring the presence of all four cysteines-and disulfide bond formation. Finally, our observations show that binding to hydrophobic short peptides drastically increases the mechanical stability of DnaJ. Altogether, our experimental approach offers a detailed, atomistic vista on the fine chemical mechanisms that govern the nanomechanics of individual, naturally occurring zinc finger.
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Affiliation(s)
- Judit Perales-Calvo
- Department of Physics and Randall Division of Cell and Molecular Biophysics, King's College London , Strand, WC2R 2LS, London, United Kingdom
| | - Ainhoa Lezamiz
- Department of Physics and Randall Division of Cell and Molecular Biophysics, King's College London , Strand, WC2R 2LS, London, United Kingdom
| | - Sergi Garcia-Manyes
- Department of Physics and Randall Division of Cell and Molecular Biophysics, King's College London , Strand, WC2R 2LS, London, United Kingdom
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Chen Y, Radford SE, Brockwell DJ. Force-induced remodelling of proteins and their complexes. Curr Opin Struct Biol 2015; 30:89-99. [PMID: 25710390 PMCID: PMC4499843 DOI: 10.1016/j.sbi.2015.02.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 01/29/2015] [Accepted: 02/02/2015] [Indexed: 11/23/2022]
Abstract
Force can drive conformational changes in proteins, as well as modulate their stability and the affinity of their complexes, allowing a mechanical input to be converted into a biochemical output. These properties have been utilised by nature and force is now recognised to be widely used at the cellular level. The effects of force on the biophysical properties of biological systems can be large and varied. As these effects are only apparent in the presence of force, studies on the same proteins using traditional ensemble biophysical methods can yield apparently conflicting results. Where appropriate, therefore, force measurements should be integrated with other experimental approaches to understand the physiological context of the system under study.
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Affiliation(s)
- Yun Chen
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK.
| | - David J Brockwell
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK.
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39
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Glyakina AV, Likhachev IV, Balabaev NK, Galzitskaya OV. Mechanical stability analysis of the protein L immunoglobulin-binding domain by full alanine screening using molecular dynamics simulations. Biotechnol J 2014; 10:386-94. [PMID: 25425165 DOI: 10.1002/biot.201400231] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 11/07/2014] [Accepted: 11/24/2014] [Indexed: 11/10/2022]
Abstract
This article is the first to study the mechanical properties of the immunoglobulin-binding domain of protein L (referred to as protein L) and its mutants at the atomic level. In the structure of protein L, each amino acid residue (except for alanines and glycines) was replaced sequentially by alanine. Thus, 49 mutants of protein L were obtained. The proteins were stretched at their termini at constant velocity using molecular dynamics simulations in water, i.e. by forced unfolding. 19 out of 49 mutations resulted in a large decrease of mechanical protein stability. These amino acids were affecting either the secondary structure (11 mutations) or loop structures (8 mutations) of protein L. Analysis of mechanical unfolding of the generated protein that has the same topology as protein L but consists of only alanines and glycines allows us to suggest that the mechanical stability of proteins, and specifically protein L, is determined by interactions between certain amino acid residues, although the unfolding pathway depends on the protein topology. This insight can now be used to modulate the mechanical properties of proteins and their unfolding pathways in the desired direction for using them in various biochips, biosensors and biomaterials for medicine, industry, and household purposes.
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Affiliation(s)
- Anna V Glyakina
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, Russia; Institute of Mathematical Problems of Biology, Russian Academy of Sciences, Pushchino, Moscow Region, Russia
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40
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Konda SSM, Avdoshenko SM, Makarov DE. Exploring the topography of the stress-modified energy landscapes of mechanosensitive molecules. J Chem Phys 2014; 140:104114. [PMID: 24628159 DOI: 10.1063/1.4867500] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We propose a method for computing the activation barrier for chemical reactions involving molecules subjected to mechanical stress. The method avoids reactant and transition-state saddle optimizations at every force by, instead, solving the differential equations governing the force dependence of the critical points (i.e., minima and saddles) on the system's potential energy surface (PES). As a result, only zero-force geometry optimization (or, more generally, optimization performed at a single force value) is required by the method. In many cases, minima and transition-state saddles only exist within a range of forces and disappear beyond a certain critical point. Our method identifies such force-induced instabilities as points at which one of the Hessian eigenvalues vanishes. We elucidate the nature of those instabilities as fold and cusp catastrophes, where two or three critical points on the force-modified PES coalesce, and provide a classification of various physically distinct instability scenarios, each illustrated with a concrete chemical example.
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Affiliation(s)
| | - Stanislav M Avdoshenko
- Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, Texas 78712, USA
| | - Dmitrii E Makarov
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, USA
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41
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Single-molecule force spectroscopy reveals force-enhanced binding of calcium ions by gelsolin. Nat Commun 2014; 5:4623. [PMID: 25100107 PMCID: PMC4143929 DOI: 10.1038/ncomms5623] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 07/08/2014] [Indexed: 01/30/2023] Open
Abstract
Force is increasingly recognized as an important element in controlling biological processes. Forces can deform native protein conformations leading to protein-specific effects. Protein–protein binding affinities may be decreased, or novel protein–protein interaction sites may be revealed, on mechanically stressing one or more components. Here we demonstrate that the calcium-binding affinity of the sixth domain of the actin-binding protein gelsolin (G6) can be enhanced by mechanical force. Our kinetic model suggests that the calcium-binding affinity of G6 increases exponentially with force, up to the point of G6 unfolding. This implies that gelsolin may be activated at lower calcium ion levels when subjected to tensile forces. The demonstration that cation–protein binding affinities can be force-dependent provides a new understanding of the complex behaviour of cation-regulated proteins in stressful cellular environments, such as those found in the cytoskeleton-rich leading edge and at cell adhesions. The application of force can influence biological processes such as ligand and protein–protein binding, with mechanical stress typically hindering such interactions. Here, the authors use atomic force microscopy to show that the binding of calcium to gelsolin can be improved under stress.
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42
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Gerhardt A, Mcgraw NR, Schwartz DK, Bee JS, Carpenter JF, Randolph TW. Protein Aggregation and Particle Formation in Prefilled Glass Syringes. J Pharm Sci 2014; 103:1601-12. [DOI: 10.1002/jps.23973] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Revised: 03/10/2014] [Accepted: 03/25/2014] [Indexed: 12/12/2022]
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43
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Kurylowicz M, Paulin H, Mogyoros J, Giuliani M, Dutcher JR. The effect of nanoscale surface curvature on the oligomerization of surface-bound proteins. J R Soc Interface 2014; 11:20130818. [PMID: 24573329 PMCID: PMC3973352 DOI: 10.1098/rsif.2013.0818] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 02/03/2014] [Indexed: 11/12/2022] Open
Abstract
The influence of surface topography on protein conformation and association is used routinely in biological cells to orchestrate and coordinate biomolecular events. In the laboratory, controlling the surface curvature at the nanoscale offers new possibilities for manipulating protein-protein interactions and protein function at surfaces. We have studied the effect of surface curvature on the association of two proteins, α-lactalbumin (α-LA) and β-lactoglobulin (β-LG), which perform their function at the oil-water interface in milk emulsions. To control the surface curvature at the nanoscale, we have used a combination of polystyrene (PS) nanoparticles (NPs) and ultrathin PS films to fabricate chemically pure, hydrophobic surfaces that are highly curved and are stable in aqueous buffer. We have used single-molecule force spectroscopy to measure the contour lengths Lc for α-LA and β-LG adsorbed on highly curved PS surfaces (NP diameters of 27 and 50 nm, capped with a 10 nm thick PS film), and we have compared these values in situ with those measured for the same proteins adsorbed onto flat PS surfaces in the same samples. The Lc distributions for β-LG adsorbed onto a flat PS surface contain monomer and dimer peaks at 60 and 120 nm, respectively, while α-LA contains a large monomer peak near 50 nm and a dimer peak at 100 nm, with a tail extending out to 200 nm, corresponding to higher order oligomers, e.g. trimers and tetramers. When β-LG or α-LA is adsorbed onto the most highly curved surfaces, both monomer peaks are shifted to much smaller values of Lc. Furthermore, for β-LG, the dimer peak is strongly suppressed on the highly curved surface, whereas for α-LA the trimer and tetramer tail is suppressed with no significant change in the dimer peak. For both proteins, the number of higher order oligomers is significantly reduced as the curvature of the underlying surface is increased. These results suggest that the surface curvature provides a new method of manipulating protein-protein interactions and controlling the association of adsorbed proteins, with applications to the development of novel biosensors.
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Affiliation(s)
| | | | | | | | - J. R. Dutcher
- Department of Physics, University of Guelph, Guelph, Ontario, CanadaN1G 2W1
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Ramanujam V, Kotamarthi HC, Ainavarapu SRK. Ca2+ binding enhanced mechanical stability of an archaeal crystallin. PLoS One 2014; 9:e94513. [PMID: 24728085 PMCID: PMC3984160 DOI: 10.1371/journal.pone.0094513] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 03/12/2014] [Indexed: 12/22/2022] Open
Abstract
Structural topology plays an important role in protein mechanical stability. Proteins with β-sandwich topology consisting of Greek key structural motifs, for example, I27 of muscle titin and 10FNIII of fibronectin, are mechanically resistant as shown by single-molecule force spectroscopy (SMFS). In proteins with β-sandwich topology, if the terminal strands are directly connected by backbone H-bonding then this geometry can serve as a “mechanical clamp”. Proteins with this geometry are shown to have very high unfolding forces. Here, we set out to explore the mechanical properties of a protein, M-crystallin, which belongs to β-sandwich topology consisting of Greek key motifs but its overall structure lacks the “mechanical clamp” geometry at the termini. M-crystallin is a Ca2+ binding protein from Methanosarcina acetivorans that is evolutionarily related to the vertebrate eye lens β and γ-crystallins. We constructed an octamer of crystallin, (M-crystallin)8, and using SMFS, we show that M-crystallin unfolds in a two-state manner with an unfolding force ∼90 pN (at a pulling speed of 1000 nm/sec), which is much lower than that of I27. Our study highlights that the β-sandwich topology proteins with a different strand-connectivity than that of I27 and 10FNIII, as well as lacking “mechanical clamp” geometry, can be mechanically resistant. Furthermore, Ca2+ binding not only stabilizes M-crystallin by 11.4 kcal/mol but also increases its unfolding force by ∼35 pN at the same pulling speed. The differences in the mechanical properties of apo and holo M-crystallins are further characterized using pulling speed dependent measurements and they show that Ca2+ binding reduces the unfolding potential width from 0.55 nm to 0.38 nm. These results are explained using a simple two-state unfolding energy landscape.
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Affiliation(s)
- Venkatraman Ramanujam
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Colaba, Mumbai, India
| | - Hema Chandra Kotamarthi
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Colaba, Mumbai, India
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45
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Nanomechanics of β-rich proteins related to neuronal disorders studied by AFM, all-atom and coarse-grained MD methods. J Mol Model 2014; 20:2144. [PMID: 24562857 PMCID: PMC3964301 DOI: 10.1007/s00894-014-2144-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 01/12/2014] [Indexed: 11/25/2022]
Abstract
Computer simulations of protein unfolding substantially help to interpret force-extension curves measured in single-molecule atomic force microscope (AFM) experiments. Standard all-atom (AA) molecular dynamics simulations (MD) give a good qualitative mechanical unfolding picture but predict values too large for the maximum AFM forces with the common pulling speeds adopted here. Fine tuned coarse-grain MD computations (CG MD) offer quantitative agreement with experimental forces. In this paper we address an important methodological aspect of MD modeling, namely the impact of numerical noise generated by random assignments of bead velocities on maximum forces (Fmax) calculated within the CG MD approach. Distributions of CG forces from 2000 MD runs for several model proteins rich in β structures and having folds with increasing complexity are presented. It is shown that Fmax have nearly Gaussian distributions and that values of Fmax for each of those β-structures may vary from 93.2 ± 28.9 pN (neurexin) to 198.3 ± 25.2 pN (fibronectin). The CG unfolding spectra are compared with AA steered MD data and with results of our AFM experiments for modules present in contactin, fibronectin and neurexin. The stability of these proteins is critical for the proper functioning of neuronal synaptic clefts. Our results confirm that CG modeling of a single molecule unfolding is a good auxiliary tool in nanomechanics but large sets of data have to be collected before reliable comparisons of protein mechanical stabilities are made. Computational strechnings of single protein modeules leads to broad distributions of unfolding forces ![]()
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Glyakina AV, Balabaev NK, Galzitskaya OV. Experimental and theoretical studies of mechanical unfolding of different proteins. BIOCHEMISTRY (MOSCOW) 2014; 78:1216-27. [PMID: 24460936 DOI: 10.1134/s0006297913110023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mechanical properties of proteins are important for a wide range of biological processes including cell adhesion, muscle contraction, and protein translocation across biological membranes. It is necessary to reveal how proteins achieve their required mechanical stability under natural conditions in order to understand the biological processes and also to use the knowledge for constructing new biomaterials for medical and industrial purposes. In this connection, it is important to know how a protein will behave in response to various impacts. Theoretical and experimental works on mechanical unfolding of globular proteins will be considered in detail in this review.
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Affiliation(s)
- A V Glyakina
- Institute of Mathematical Problems of Biology, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
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Kotamarthi HC, Sharma R, Koti Ainavarapu SR. Single-molecule studies on PolySUMO proteins reveal their mechanical flexibility. Biophys J 2013; 104:2273-81. [PMID: 23708367 DOI: 10.1016/j.bpj.2013.04.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 04/04/2013] [Accepted: 04/05/2013] [Indexed: 01/08/2023] Open
Abstract
Proteins with β-sandwich and β-grasp topologies are resistant to mechanical unfolding as shown by single-molecule force spectroscopy studies. Their high mechanical stability has generally been associated with the mechanical clamp geometry present at the termini. However, there is also evidence for the importance of interactions other than the mechanical clamp in providing mechanical stability, which needs to be tested thoroughly. Here, we report the mechanical unfolding properties of ubiquitin-like proteins (SUMO1 and SUMO2) and their comparison with those of ubiquitin. Although ubiquitin and SUMOs have similar size and structural topology, they differ in their sequences and structural contacts, making them ideal candidates to understand the variations in the mechanical stability of a given protein topology. We observe a two-state unfolding pathway for SUMO1 and SUMO2, similar to that of ubiquitin. Nevertheless, the unfolding forces of SUMO1 (∼130 pN) and SUMO2 (∼120 pN) are lower than that of ubiquitin (∼190 pN) at a pulling speed of 400 nm/s, indicating their lower mechanical stability. The mechanical stabilities of SUMO proteins and ubiquitin are well correlated with the number of interresidue contacts present in their structures. From pulling speed-dependent mechanical unfolding experiments and Monte Carlo simulations, we find that the unfolding potential widths of SUMO1 (∼0.51 nm) and SUMO2 (∼0.33 nm) are much larger than that of ubiquitin (∼0.19 nm), indicating that SUMO1 is six times and SUMO2 is three times mechanically more flexible than ubiquitin. These findings might also be important in understanding the functional differences between ubiquitin and SUMOs.
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Affiliation(s)
- Hema Chandra Kotamarthi
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Colaba, Mumbai, India
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Kotamarthi HC, Sharma R, Narayan S, Ray S, Ainavarapu SRK. Multiple Unfolding Pathways of Leucine Binding Protein (LBP) Probed by Single-Molecule Force Spectroscopy (SMFS). J Am Chem Soc 2013; 135:14768-74. [DOI: 10.1021/ja406238q] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hema Chandra Kotamarthi
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Riddhi Sharma
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Satya Narayan
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Sayoni Ray
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Sri Rama Koti Ainavarapu
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
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Glyakina AV, Likhachev IV, Balabaev NK, Galzitskaya OV. Right- and left-handed three-helix proteins. II. Similarity and differences in mechanical unfolding of proteins. Proteins 2013; 82:90-102. [PMID: 23873665 DOI: 10.1002/prot.24373] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 06/26/2013] [Accepted: 07/09/2013] [Indexed: 11/11/2022]
Abstract
Here, we study mechanical properties of eight 3-helix proteins (four right-handed and four left-handed ones), which are similar in size under stretching at a constant speed and at a constant force on the atomic level using molecular dynamics simulations. The analysis of 256 trajectories from molecular dynamics simulations with explicit water showed that the right-handed three-helix domains are more mechanically resistant than the left-handed domains. Such results are observed at different extension velocities studied (192 trajectories obtained at the following conditions: v = 0.1, 0.05, and 0.01 Å ps(-1) , T = 300 K) and under constant stretching force (64 trajectories, F = 800 pN, T = 300 K). We can explain this by the fact, at least in part, that the right-handed domains have a larger number of contacts per residue and the radius of cross section than the left-handed domains.
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Affiliation(s)
- Anna V Glyakina
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia; Institute of Mathematical Problems of Biology, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
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Hoffmann T, Tych KM, Hughes ML, Brockwell DJ, Dougan L. Towards design principles for determining the mechanical stability of proteins. Phys Chem Chem Phys 2013; 15:15767-80. [DOI: 10.1039/c3cp52142g] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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