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Apostolidou D, Zhang P, Yang W, Marszalek PE. Mechanical Unfolding and Refolding of NanoLuc via Single-Molecule Force Spectroscopy and Computer Simulations. Biomacromolecules 2022; 23:5164-5178. [PMID: 36350253 DOI: 10.1021/acs.biomac.2c00997] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A highly bioluminescent protein, NanoLuc (Nluc), has seen numerous applications in biological assays since its creation. We recently engineered a NanoLuc polyprotein that showed high bioluminescence but displayed a strong misfolding propensity after mechanical unfolding. Here, we present our single-molecule force spectroscopy (SMFS) studies by atomic force microscopy (AFM) and steered molecular dynamics (SMD) simulations on two new hybrid protein constructs comprised of Nluc and I91 titin domains, I91-I91-Nluc-I91-I91-I91-I91 (I912-Nluc-I914) and I91-Nluc-I91-Nluc-I91-Nluc-I91, to characterize the unfolding behavior of Nluc in detail and to further investigate its misfolding properties that we observed earlier for the I912-Nluc3-I912 construct. Our SMFS results confirm that Nluc's unfolding proceeds similarly in all constructs; however, Nluc's refolding differs in these constructs, and its misfolding is minimized when Nluc is monomeric or separated by I91 domains. Our simulations on monomeric Nluc, Nluc dyads, and Nluc triads pinpointed the origin of its mechanical stability and captured interesting unfolding intermediates, which we also observed experimentally.
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Affiliation(s)
- Dimitra Apostolidou
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina27708, United States
| | - Pan Zhang
- Department of Chemistry, Duke University, Durham, North Carolina27708, United States
| | - Weitao Yang
- Department of Chemistry, Duke University, Durham, North Carolina27708, United States
| | - Piotr E Marszalek
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina27708, United States
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Marszalek PE. Capturing intrinsic nanomechanics of allostery. Biophys J 2022; 121:4415-4416. [PMID: 36815705 PMCID: PMC9748355 DOI: 10.1016/j.bpj.2022.10.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 10/24/2022] [Accepted: 10/25/2022] [Indexed: 11/29/2022] Open
Abstract
The Hsp70 chaperone exploits allosteric communication between its substrate binding domain and its nucleotide binding domain to regulate the loading and release of misfolded polypeptides in an ATP-hydrolysis-dependent manner. In this issue of Biophysical Journal, Singh, Rief, and Žoldák report an exquisitely detailed study of the nanomechanical aspects of the allosteric mechanism in DnaK, an Escherichia coli heat shock protein 70 chaperone.
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Affiliation(s)
- Piotr E Marszalek
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina.
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3
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Singh A, Rief M, Žoldák G. Direct observation of chemo-mechanical coupling in DnaK by single-molecule force experiments. Biophys J 2022; 121:4729-4739. [PMID: 36196054 PMCID: PMC9748191 DOI: 10.1016/j.bpj.2022.09.042] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 09/16/2022] [Accepted: 09/29/2022] [Indexed: 12/15/2022] Open
Abstract
Protein allostery requires a communication channel for functional regulation between distal sites within a protein. In the molecular chaperone Hsp70, a two-domain enzyme, the ATP/ADP status of an N-terminal nucleotide-binding domain regulates the substrate affinity of a C-terminal substrate-binding domain. Recently available three-dimensional structures of Hsp70 in ATP/ADP states have provided deep insights into molecular pathways of allosteric signals. However, direct mechanical probing of long-range allosteric coupling between the ATP hydrolysis step and domain states is missing. Using laser optical tweezers, we examined the mechanical properties of a truncated two-domain DnaK(1-552ye) in apo/ADP/ATP- and peptide-bound states. We find that in the apo and ADP states, DnaK domains are mechanically stable and rigid. However, in the ATP state, substrate-binding domain (SBD)∗ye is mechanically destabilized as the result of interdomain docking followed by the unfolding of the α-helical lid. By observing the folding state of the SBD, we could observe the continuous ATP/ADP cycling of the enzyme in real time with a single molecule. The SBD lid closure is strictly coupled to the chemical steps of the ATP hydrolysis cycle even in the presence of peptide substrate.
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Affiliation(s)
- Anubhuti Singh
- Center for Functional Protein Assemblies (CPA), Physik Department, Technische Universität München, Garching, Germany
| | - Matthias Rief
- Center for Functional Protein Assemblies (CPA), Physik Department, Technische Universität München, Garching, Germany.
| | - Gabriel Žoldák
- Center for Interdisciplinary Biosciences, Technology and Innovation Park, P. J. Šafárik University, Košice, Slovakia; Center for Interdisciplinary Biosciences, Cassovia New Industry Cluster (CNIC), Trieda SNP 1, 040 11, Košice, Slovakia.
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Rief M, Žoldák G. Single-molecule mechanical studies of chaperones and their clients. BIOPHYSICS REVIEWS 2022; 3:041301. [PMID: 38505517 PMCID: PMC10903372 DOI: 10.1063/5.0098033] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 09/12/2022] [Indexed: 03/21/2024]
Abstract
Single-molecule force spectroscopy provides access to the mechanics of biomolecules. Recently, magnetic and laser optical tweezers were applied in the studies of chaperones and their interaction with protein clients. Various aspects of the chaperone-client interactions can be revealed based on the mechanical probing strategies. First, when a chaperone is probed under load, one can examine the inner workings of the chaperone while it interacts with and works on the client protein. Second, when protein clients are probed under load, the action of chaperones on folding clients can be studied in great detail. Such client folding studies have given direct access to observing actions of chaperones in real-time, like foldase, unfoldase, and holdase activity. In this review, we introduce the various single molecule mechanical techniques and summarize recent single molecule mechanical studies on heat shock proteins, chaperone-mediated folding on the ribosome, SNARE folding, and studies of chaperones involved in the folding of membrane proteins. An outlook on significant future developments is given.
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Affiliation(s)
- Matthias Rief
- Center for Functional Protein Assemblies (CPA), Physik Department, Technische Universität München, Ernst-Otto-Fischer-Str., 8, D-85748 Garching, Germany
| | - Gabriel Žoldák
- Center for Interdisciplinary Biosciences, Technology and Innovation Park, P. J. Šafárik University, Trieda SNP 1, 040 11 Košice, Slovakia
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Bauer J, Žoldák G. Interpretation of Single-Molecule Force Experiments on Proteins Using Normal Mode Analysis. NANOMATERIALS 2021; 11:nano11112795. [PMID: 34835560 PMCID: PMC8624234 DOI: 10.3390/nano11112795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/20/2021] [Accepted: 10/20/2021] [Indexed: 11/25/2022]
Abstract
Single-molecule force spectroscopy experiments allow protein folding and unfolding to be explored using mechanical force. Probably the most informative technique for interpreting the results of these experiments at the structural level makes use of steered molecular dynamics (MD) simulations, which can explicitly model the protein under load. Unfortunately, this technique is computationally expensive for many of the most interesting biological molecules. Here, we find that normal mode analysis (NMA), a significantly cheaper technique from a computational perspective, allows at least some of the insights provided by MD simulation to be gathered. We apply this technique to three non-homologous proteins that were previously studied by force spectroscopy: T4 lysozyme (T4L), Hsp70 and the glucocorticoid receptor domain (GCR). The NMA results for T4L and Hsp70 are compared with steered MD simulations conducted previously, and we find that we can recover the main results. For the GCR, which did not undergo MD simulation, our approach identifies substructures that correlate with experimentally identified unfolding intermediates. Overall, we find that NMA can make a valuable addition to the analysis toolkit for the structural analysis of single-molecule force experiments on proteins.
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Affiliation(s)
- Jacob Bauer
- Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia
- Correspondence: (J.B.); (G.Ž.); Tel.: +421-55-234-2242 (G.Ž.)
| | - Gabriel Žoldák
- Center for Interdisciplinary Biosciences, P. J. Šafárik University, Technology and Innovation Park, Trieda SNP 1, 041 54 Košice, Slovakia
- Correspondence: (J.B.); (G.Ž.); Tel.: +421-55-234-2242 (G.Ž.)
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Bartels K, Lasitza‐Male T, Hofmann H, Löw C. Single-Molecule FRET of Membrane Transport Proteins. Chembiochem 2021; 22:2657-2671. [PMID: 33945656 PMCID: PMC8453700 DOI: 10.1002/cbic.202100106] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/03/2021] [Indexed: 12/31/2022]
Abstract
Uncovering the structure and function of biomolecules is a fundamental goal in structural biology. Membrane-embedded transport proteins are ubiquitous in all kingdoms of life. Despite structural flexibility, their mechanisms are typically studied by ensemble biochemical methods or by static high-resolution structures, which complicate a detailed understanding of their dynamics. Here, we review the recent progress of single molecule Förster Resonance Energy Transfer (smFRET) in determining mechanisms and timescales of substrate transport across membranes. These studies do not only demonstrate the versatility and suitability of state-of-the-art smFRET tools for studying membrane transport proteins but they also highlight the importance of membrane mimicking environments in preserving the function of these proteins. The current achievements advance our understanding of transport mechanisms and have the potential to facilitate future progress in drug design.
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Affiliation(s)
- Kim Bartels
- Centre for Structural Systems Biology (CSSB)DESY and European Molecular Biology Laboratory HamburgNotkestrasse 8522607HamburgGermany
| | - Tanya Lasitza‐Male
- Department of Structural BiologyWeizmann Institute of ScienceHerzl St. 2347610001RehovotIsrael
| | - Hagen Hofmann
- Department of Structural BiologyWeizmann Institute of ScienceHerzl St. 2347610001RehovotIsrael
| | - Christian Löw
- Centre for Structural Systems Biology (CSSB)DESY and European Molecular Biology Laboratory HamburgNotkestrasse 8522607HamburgGermany
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Gala M, Žoldák G. Classifying Residues in Mechanically Stable and Unstable Substructures Based on a Protein Sequence: The Case Study of the DnaK Hsp70 Chaperone. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:2198. [PMID: 34578514 PMCID: PMC8467864 DOI: 10.3390/nano11092198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 08/16/2021] [Accepted: 08/24/2021] [Indexed: 12/17/2022]
Abstract
Artificial proteins can be constructed from stable substructures, whose stability is encoded in their protein sequence. Identifying stable protein substructures experimentally is the only available option at the moment because no suitable method exists to extract this information from a protein sequence. In previous research, we examined the mechanics of E. coli Hsp70 and found four mechanically stable (S class) and three unstable substructures (U class). Of the total 603 residues in the folded domains of Hsp70, 234 residues belong to one of four mechanically stable substructures, and 369 residues belong to one of three unstable substructures. Here our goal is to develop a machine learning model to categorize Hsp70 residues using sequence information. We applied three supervised methods: logistic regression (LR), random forest, and support vector machine. The LR method showed the highest accuracy, 0.925, to predict the correct class of a particular residue only when context-dependent physico-chemical features were included. The cross-validation of the LR model yielded a prediction accuracy of 0.879 and revealed that most of the misclassified residues lie at the borders between substructures. We foresee machine learning models being used to identify stable substructures as candidates for building blocks to engineer new proteins.
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Affiliation(s)
- Michal Gala
- Department of Biophysics, Faculty of Science, P. J. Šafárik University, Jesena 5, 040 01 Košice, Slovakia;
| | - Gabriel Žoldák
- Center for Interdisciplinary Biosciences, Technology and Innovation Park, P. J. Šafárik University, Trieda SNP 1, 040 11 Košice, Slovakia
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Li Q, Apostolidou D, Marszalek PE. Reconstruction of mechanical unfolding and refolding pathways of proteins with atomic force spectroscopy and computer simulations. Methods 2021; 197:39-53. [PMID: 34020035 DOI: 10.1016/j.ymeth.2021.05.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 05/14/2021] [Accepted: 05/15/2021] [Indexed: 12/29/2022] Open
Abstract
Most proteins in proteomes are large, typically consist of more than one domain and are structurally complex. This often makes studying their mechanical unfolding pathways challenging. Proteins composed of tandem repeat domains are a subgroup of multi-domain proteins that, when stretched, display a saw-tooth pattern in their mechanical unfolding force extension profiles due to their repetitive structure. However, the assignment of force peaks to specific repeats undergoing mechanical unraveling is complicated because all repeats are similar and they interact with their neighbors and form a contiguous tertiary structure. Here, we describe in detail a combination of experimental and computational single-molecule force spectroscopy methods that proved useful for examining the mechanical unfolding and refolding pathways of ankyrin repeat proteins. Specifically, we explain and delineate the use of atomic force microscope-based single molecule force spectroscopy (SMFS) to record the mechanical unfolding behavior of ankyrin repeat proteins and capture their unusually strong refolding propensity that is responsible for generating impressive refolding force peaks. We also describe Coarse Grain Steered Molecular Dynamic (CG-SMD) simulations which complement the experimental observations and provide insights in understanding the unfolding and refolding of these proteins. In addition, we advocate the use of novel coiled-coils-based mechanical polypeptide probes which we developed to demonstrate the vectorial character of folding and refolding of these repeat proteins. The combination of AFM-based SMFS on native and CC-equipped proteins with CG-SMD simulations is powerful not only for ankyrin repeat polypeptides, but also for other repeat proteins and more generally to various multidomain, non-repetitive proteins with complex topologies.
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Affiliation(s)
- Qing Li
- Department of Mechanical Engineering and Materials Science, Duke University, 27708 Durham, NC, United States
| | - Dimitra Apostolidou
- Department of Mechanical Engineering and Materials Science, Duke University, 27708 Durham, NC, United States
| | - Piotr E Marszalek
- Department of Mechanical Engineering and Materials Science, Duke University, 27708 Durham, NC, United States.
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From folding to function: complex macromolecular reactions unraveled one-by-one with optical tweezers. Essays Biochem 2021; 65:129-142. [PMID: 33438724 DOI: 10.1042/ebc20200024] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 12/08/2020] [Accepted: 12/11/2020] [Indexed: 12/13/2022]
Abstract
Single-molecule manipulation with optical tweezers has uncovered macromolecular behaviour hidden to other experimental techniques. Recent instrumental improvements have made it possible to expand the range of systems accessible to optical tweezers. Beyond focusing on the folding and structural changes of isolated single molecules, optical tweezers studies have evolved into unraveling the basic principles of complex molecular processes such as co-translational folding on the ribosome, kinase activation dynamics, ligand-receptor binding, chaperone-assisted protein folding, and even dynamics of intrinsically disordered proteins (IDPs). In this mini-review, we illustrate the methodological principles of optical tweezers before highlighting recent advances in studying complex protein conformational dynamics - from protein synthesis to physiological function - as well as emerging future issues that are beginning to be addressed with novel approaches.
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Udgaonkar JB. Introducing the Mechanical Forces in Biochemistry Special Issue. Biochemistry 2020; 58:4655-4656. [PMID: 31766850 DOI: 10.1021/acs.biochem.9b00999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jayant B Udgaonkar
- Indian Institute of Science Education and Research , Pune 411008 , India.,National Centre for Biological Sciences , Tata Institute of Fundamental Research , Bengaluru 560065 , India
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