1
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Freitag M, Jaklin S, Padovani F, Radzichevici E, Zernia S, Schmoller KM, Stigler J. Single-molecule experiments reveal the elbow as an essential folding guide in SMC coiled-coil arms. Biophys J 2022; 121:4702-4713. [PMID: 36242515 PMCID: PMC9748247 DOI: 10.1016/j.bpj.2022.10.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 09/16/2022] [Accepted: 10/12/2022] [Indexed: 11/19/2022] Open
Abstract
Structural maintenance of chromosome (SMC) complexes form ring-like structures through exceptional elongated coiled-coils (CCs). Recent studies found that variable CC conformations, including open and collapsed forms, which might result from discontinuities in the CC, facilitate the diverse functions of SMCs in DNA organization. However, a detailed description of the SMC CC architecture is still missing. Here, we study the structural composition and mechanical properties of SMC proteins with optical tweezers unfolding experiments using the isolated Psm3 CC as a model system. We find a comparatively unstable protein with three unzipping intermediates, which we could directly assign to CC features by crosslinking experiments and state-of-the-art prediction software. Particularly, the CC elbow is shown to be a flexible, potentially non-structured feature, which divides the CC into sections, induces a pairing shift from one CC strand to the other and could facilitate large-scale conformational changes, most likely via thermal fluctuations of the flanking CC sections. A replacement of the elbow amino acids hinders folding of the consecutive CC region and frequently leads to non-native misalignments, revealing the elbow as a guide for proper folding. Additional in vivo manipulation of the elbow flexibility resulted in impaired cohesin complexes, which directly link the sensitive CC architecture to the biological function of cohesin.
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Affiliation(s)
- Marvin Freitag
- Gene Center Munich, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Sigrun Jaklin
- Gene Center Munich, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Francesco Padovani
- Institute of Functional Epigenetics, Helmholtz Zentrum München, Neuherberg, Germany
| | | | - Sarah Zernia
- Gene Center Munich, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Kurt M Schmoller
- Institute of Functional Epigenetics, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Johannes Stigler
- Gene Center Munich, Ludwig-Maximilians-Universität München, Munich, Germany.
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2
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Tych K, Rief M. Using Single-Molecule Optical Tweezers to Study the Conformational Cycle of the Hsp90 Molecular Chaperone. Methods Mol Biol 2022; 2478:401-425. [PMID: 36063329 DOI: 10.1007/978-1-0716-2229-2_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The heat shock protein 90 (Hsp90) family of chaperones are well-known, highly important components of the cellular systems which regulate protein homeostasis. Essential in eukaryotes, Hsp90s is also found in prokaryotes, including archaea. Hsp90 is a dimeric protein, with each monomer consisting of three separate structural domains, and undergoes large conformational changes as part of its functional cycle. This cycle is driven by interactions with nucleotides, cochaperone proteins, client proteins and allosteric effects enacted by these and by posttranslational modifications. All of these influence the rate and degree of the opening and closing of the dimer as well as the relative domain orientations and its overall rigidity. Optical tweezers, which can access many of these functionally important conformational changes, therefore provide a unique tool for the study of this large and complex molecular chaperone. Here, we provide protocols for the design and implementation of different Hsp90 constructs and optical tweezers experiments for addressing the many open questions about the function of this important molecular chaperone.
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Affiliation(s)
- Katarzyna Tych
- Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Groningen, The Netherlands.
| | - Matthias Rief
- Department of Physics, Technical University of Munich, Garching-bei-München, Germany.
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3
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Abstract
This paper provides a perspective on potential applications of a new single-molecule technique, viz., the nanopore electro-osmotic trap (NEOtrap). This solid-state nanopore-based method uses locally induced electro-osmosis to form a hydrodynamic trap for single molecules. Ionic current recordings allow one to study an unlabeled protein or nanoparticle of arbitrary charge that can be held in the nanopore's most sensitive region for very long times. After motivating the need for improved single-molecule technologies, we sketch various possible technical extensions and combinations of the NEOtrap. We lay out diverse applications in biosensing, enzymology, protein folding, protein dynamics, fingerprinting of proteins, detecting post-translational modifications, and all that at the level of single proteins - illustrating the unique versatility and potential of the NEOtrap.
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Affiliation(s)
- Sonja Schmid
- Nanodynamics Lab, Laboratory of Biophysics, Wageningen University, Stippeneng 4, 6708WE Wageningen, the Netherlands
| | - Cees Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, the Netherlands
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4
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Shinde A, Illath K, Gupta P, Shinde P, Lim KT, Nagai M, Santra TS. A Review of Single-Cell Adhesion Force Kinetics and Applications. Cells 2021; 10:577. [PMID: 33808043 PMCID: PMC8000588 DOI: 10.3390/cells10030577] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/01/2021] [Accepted: 03/02/2021] [Indexed: 02/06/2023] Open
Abstract
Cells exert, sense, and respond to the different physical forces through diverse mechanisms and translating them into biochemical signals. The adhesion of cells is crucial in various developmental functions, such as to maintain tissue morphogenesis and homeostasis and activate critical signaling pathways regulating survival, migration, gene expression, and differentiation. More importantly, any mutations of adhesion receptors can lead to developmental disorders and diseases. Thus, it is essential to understand the regulation of cell adhesion during development and its contribution to various conditions with the help of quantitative methods. The techniques involved in offering different functionalities such as surface imaging to detect forces present at the cell-matrix and deliver quantitative parameters will help characterize the changes for various diseases. Here, we have briefly reviewed single-cell mechanical properties for mechanotransduction studies using standard and recently developed techniques. This is used to functionalize from the measurement of cellular deformability to the quantification of the interaction forces generated by a cell and exerted on its surroundings at single-cell with attachment and detachment events. The adhesive force measurement for single-cell microorganisms and single-molecules is emphasized as well. This focused review should be useful in laying out experiments which would bring the method to a broader range of research in the future.
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Affiliation(s)
- Ashwini Shinde
- Department of Engineering Design, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India; (A.S.); (K.I.); (P.G.); (P.S.)
| | - Kavitha Illath
- Department of Engineering Design, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India; (A.S.); (K.I.); (P.G.); (P.S.)
| | - Pallavi Gupta
- Department of Engineering Design, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India; (A.S.); (K.I.); (P.G.); (P.S.)
| | - Pallavi Shinde
- Department of Engineering Design, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India; (A.S.); (K.I.); (P.G.); (P.S.)
| | - Ki-Taek Lim
- Department of Biosystems Engineering, Kangwon National University, Chuncheon-Si, Gangwon-Do 24341, Korea;
| | - Moeto Nagai
- Department of Mechanical Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580, Japan;
| | - Tuhin Subhra Santra
- Department of Engineering Design, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India; (A.S.); (K.I.); (P.G.); (P.S.)
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5
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Liu SX, Lü G, Zhang H, Geng YZ, Ji Q. Origin of the Surprising Mechanical Stability of Kinesin's Neck Coiled Coil. J Chem Theory Comput 2021; 17:1017-1029. [PMID: 33512152 DOI: 10.1021/acs.jctc.0c00566] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Kinesin-1 is a motor protein moving along a microtubule with its two identical motor heads dimerized by two neck linkers and a coiled-coil stalk. When both motor heads bind the microtubule, an internal strain is built up between the two heads, which is indispensable to ensure proper coordination of the two motor heads during kinesin-1's mechanochemical cycle. The internal strain forms a tensile force along the neck linker that tends to unwind the neck coiled coil (NCC). Experiments showed that the kinesin-1's NCC has a high antiunwinding ability compared with conventional coiled coils, which was mainly attributed to the enhanced hydrophobic pressure arising from the unconventional sequence of kinesin-1's NCC. However, hydrophobic pressure cannot provide the shearing force which is needed to balance the tensile force on the interface between two helices. To find out the true origin of the mechanical stability of kinesin-1's NCC, we perform a novel and detailed mechanical analysis for the system based on molecular dynamics simulation at an atomic level. We find that the needed shearing force is provided by a buckle structure formed by two tyrosines which form effective steric hindrance in the presence of tensile forces. The tensile force is balanced by the tensile direction component of the contact force between the two tyrosines which forms the shearing force. The hydrophobic pressure balances the other component of the contact force perpendicular to the tensile direction. The antiunwinding strength of NCC is defined by the maximum shearing force, which is finally determined by the hydrophobic pressure. Kinesin-1 uses residues with plane side chains, tryptophans and tyrosines, to form the hydrophobic center and to shorten the interhelix distance so that a high antiunwinding strength is obtained. The special design of NCC ensures exquisite cooperation of steric hindrance and hydrophobic pressure that results in the surprising mechanical stability of NCC.
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Affiliation(s)
- Shu-Xia Liu
- Institute of Biophysics, Hebei University of Technology, Tianjin 300401, China
| | - Gang Lü
- Mathematical and Physical Science School, North China Electric Power University, Baoding 071003, China
| | - Hui Zhang
- School of Science, Hebei University of Technology, Tianjin 300401, China
| | - Yi-Zhao Geng
- Institute of Biophysics, Hebei University of Technology, Tianjin 300401, China.,School of Science, Hebei University of Technology, Tianjin 300401, China
| | - Qing Ji
- Institute of Biophysics, Hebei University of Technology, Tianjin 300401, China.,School of Science, Hebei University of Technology, Tianjin 300401, China.,State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, China
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6
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Yang B, Liu Z, Liu H, Nash MA. Next Generation Methods for Single-Molecule Force Spectroscopy on Polyproteins and Receptor-Ligand Complexes. Front Mol Biosci 2020; 7:85. [PMID: 32509800 PMCID: PMC7248566 DOI: 10.3389/fmolb.2020.00085] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 04/16/2020] [Indexed: 12/31/2022] Open
Abstract
Single-molecule force spectroscopy with the atomic force microscope provides molecular level insights into protein function, allowing researchers to reconstruct energy landscapes and understand functional mechanisms in biology. With steadily advancing methods, this technique has greatly accelerated our understanding of force transduction, mechanical deformation, and mechanostability within single- and multi-domain polyproteins, and receptor-ligand complexes. In this focused review, we summarize the state of the art in terms of methodology and highlight recent methodological improvements for AFM-SMFS experiments, including developments in surface chemistry, considerations for protein engineering, as well as theory and algorithms for data analysis. We hope that by condensing and disseminating these methods, they can assist the community in improving data yield, reliability, and throughput and thereby enhance the information that researchers can extract from such experiments. These leading edge methods for AFM-SMFS will serve as a groundwork for researchers cognizant of its current limitations who seek to improve the technique in the future for in-depth studies of molecular biomechanics.
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Affiliation(s)
- Byeongseon Yang
- Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Zhaowei Liu
- Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Haipei Liu
- Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Michael A. Nash
- Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
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7
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Goktas M, Luo C, Sullan RMA, Bergues-Pupo AE, Lipowsky R, Vila Verde A, Blank KG. Molecular mechanics of coiled coils loaded in the shear geometry. Chem Sci 2018; 9:4610-4621. [PMID: 29899954 PMCID: PMC5969510 DOI: 10.1039/c8sc01037d] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 04/19/2018] [Indexed: 01/25/2023] Open
Abstract
Coiled coils are important nanomechanical building blocks in biological and biomimetic materials. A mechanistic molecular understanding of their structural response to mechanical load is essential for elucidating their role in tissues and for utilizing and tuning these building blocks in materials applications. Using a combination of single-molecule force spectroscopy (SMFS) and steered molecular dynamics (SMD) simulations, we have investigated the mechanics of synthetic heterodimeric coiled coils of different length (3-4 heptads) when loaded in shear geometry. Upon shearing, we observe an initial rise in the force, which is followed by a constant force plateau and ultimately strand separation. The force required for strand separation depends on the coiled coil length and the applied loading rate, suggesting that coiled coil shearing occurs out of equilibrium. This out-of-equilibrium behaviour is determined by a complex structural response which involves helix uncoiling, uncoiling-assisted sliding of the helices relative to each other in the direction of the applied force as well as uncoiling-assisted dissociation perpendicular to the force axis. These processes follow a hierarchy of timescales with helix uncoiling being faster than sliding and sliding being faster than dissociation. In SMFS experiments, strand separation is dominated by uncoiling-assisted dissociation and occurs at forces between 25-45 pN for the shortest 3-heptad coiled coil and between 35-50 pN for the longest 4-heptad coiled coil. These values are highly similar to the forces required for shearing apart short double-stranded DNA oligonucleotides, reinforcing the potential role of coiled coils as nanomechanical building blocks in applications where protein-based structures are desired.
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Affiliation(s)
- Melis Goktas
- Max Planck Institute of Colloids and Interfaces , Mechano(bio)chemistry , Science Park Potsdam-Golm , 14424 Potsdam , Germany .
| | - Chuanfu Luo
- Max Planck Institute of Colloids and Interfaces , Department of Theory & Bio-Systems , Science Park Potsdam-Golm , 14424 Potsdam , Germany .
| | - Ruby May A Sullan
- Max Planck Institute of Colloids and Interfaces , Mechano(bio)chemistry , Science Park Potsdam-Golm , 14424 Potsdam , Germany .
| | - Ana E Bergues-Pupo
- Max Planck Institute of Colloids and Interfaces , Department of Theory & Bio-Systems , Science Park Potsdam-Golm , 14424 Potsdam , Germany .
| | - Reinhard Lipowsky
- Max Planck Institute of Colloids and Interfaces , Department of Theory & Bio-Systems , Science Park Potsdam-Golm , 14424 Potsdam , Germany .
| | - Ana Vila Verde
- Max Planck Institute of Colloids and Interfaces , Department of Theory & Bio-Systems , Science Park Potsdam-Golm , 14424 Potsdam , Germany .
| | - Kerstin G Blank
- Max Planck Institute of Colloids and Interfaces , Mechano(bio)chemistry , Science Park Potsdam-Golm , 14424 Potsdam , Germany .
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8
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Guzik-Lendrum S, Rank KC, Bensel BM, Taylor KC, Rayment I, Gilbert SP. Kinesin-2 KIF3AC and KIF3AB Can Drive Long-Range Transport along Microtubules. Biophys J 2016; 109:1472-82. [PMID: 26445448 DOI: 10.1016/j.bpj.2015.08.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 08/03/2015] [Accepted: 08/04/2015] [Indexed: 12/14/2022] Open
Abstract
Mammalian KIF3AC is classified as a heterotrimeric kinesin-2 that is best known for organelle transport in neurons, yet in vitro studies to characterize its single molecule behavior are lacking. The results presented show that a KIF3AC motor that includes the native helix α7 sequence for coiled-coil formation is highly processive with run lengths of ∼1.23 μm and matching those exhibited by conventional kinesin-1. This result was unexpected because KIF3AC exhibits the canonical kinesin-2 neck-linker sequence that has been reported to be responsible for shorter run lengths observed for another heterotrimeric kinesin-2, KIF3AB. However, KIF3AB with its native neck linker and helix α7 is also highly processive with run lengths of ∼1.62 μm and exceeding those of KIF3AC and kinesin-1. Loop L11, a component of the microtubule-motor interface and implicated in activating ADP release upon microtubule collision, is significantly extended in KIF3C as compared with other kinesins. A KIF3AC encoding a truncation in KIF3C loop L11 (KIF3ACΔL11) exhibited longer run lengths at ∼1.55 μm than wild-type KIF3AC and were more similar to KIF3AB run lengths, suggesting that L11 also contributes to tuning motor processivity. The steady-state ATPase results show that shortening L11 does not alter kcat, consistent with the observation that single molecule velocities are not affected by this truncation. However, shortening loop L11 of KIF3C significantly increases the microtubule affinity of KIF3ACΔL11, revealing another structural and mechanistic property that can modulate processivity. The results presented provide new, to our knowledge, insights to understand structure-function relationships governing processivity and a better understanding of the potential of KIF3AC for long-distance transport in neurons.
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Affiliation(s)
- Stephanie Guzik-Lendrum
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York
| | - Katherine C Rank
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin
| | - Brandon M Bensel
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York
| | - Keenan C Taylor
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin
| | - Ivan Rayment
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin.
| | - Susan P Gilbert
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York.
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9
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Phillips RK, Peter LG, Gilbert SP, Rayment I. Family-specific Kinesin Structures Reveal Neck-linker Length Based on Initiation of the Coiled-coil. J Biol Chem 2016; 291:20372-86. [PMID: 27462072 DOI: 10.1074/jbc.m116.737577] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Indexed: 12/24/2022] Open
Abstract
Kinesin-1, -2, -5, and -7 generate processive hand-over-hand 8-nm steps to transport intracellular cargoes toward the microtubule plus end. This processive motility requires gating mechanisms to coordinate the mechanochemical cycles of the two motor heads to sustain the processive run. A key structural element believed to regulate the degree of processivity is the neck-linker, a short peptide of 12-18 residues, which connects the motor domain to its coiled-coil stalk. Although a shorter neck-linker has been correlated with longer run lengths, the structural data to support this hypothesis have been lacking. To test this hypothesis, seven kinesin structures were determined by x-ray crystallography. Each included the neck-linker motif, followed by helix α7 that constitutes the start of the coiled-coil stalk. In the majority of the structures, the neck-linker length differed from predictions because helix α7, which initiates the coiled-coil, started earlier in the sequence than predicted. A further examination of structures in the Protein Data Bank reveals that there is a great disparity between the predicted and observed starting residues. This suggests that an accurate prediction of the start of a coiled-coil is currently difficult to achieve. These results are significant because they now exclude simple comparisons between members of the kinesin superfamily and add a further layer of complexity when interpreting the results of mutagenesis or protein fusion. They also re-emphasize the need to consider factors beyond the kinesin neck-linker motif when attempting to understand how inter-head communication is tuned to achieve the degree of processivity required for cellular function.
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Affiliation(s)
- Rebecca K Phillips
- From the Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706 and
| | - Logan G Peter
- From the Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706 and
| | - Susan P Gilbert
- the Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180
| | - Ivan Rayment
- From the Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706 and
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10
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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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11
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Nam W, Epureanu BI. Effects of Obstacles on the Dynamics of Kinesins, Including Velocity and Run Length, Predicted by a Model of Two Dimensional Motion. PLoS One 2016; 11:e0147676. [PMID: 26808534 PMCID: PMC4726810 DOI: 10.1371/journal.pone.0147676] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 01/06/2016] [Indexed: 02/07/2023] Open
Abstract
Kinesins are molecular motors which walk along microtubules by moving their heads to different binding sites. The motion of kinesin is realized by a conformational change in the structure of the kinesin molecule and by a diffusion of one of its two heads. In this study, a novel model is developed to account for the 2D diffusion of kinesin heads to several neighboring binding sites (near the surface of microtubules). To determine the direction of the next step of a kinesin molecule, this model considers the extension in the neck linkers of kinesin and the dynamic behavior of the coiled-coil structure of the kinesin neck. Also, the mechanical interference between kinesins and obstacles anchored on the microtubules is characterized. The model predicts that both the kinesin velocity and run length (i.e., the walking distance before detaching from the microtubule) are reduced by static obstacles. The run length is decreased more significantly by static obstacles than the velocity. Moreover, our model is able to predict the motion of kinesin when other (several) motors also move along the same microtubule. Furthermore, it suggests that the effect of mechanical interaction/interference between motors is much weaker than the effect of static obstacles. Our newly developed model can be used to address unanswered questions regarding degraded transport caused by the presence of excessive tau proteins on microtubules.
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Affiliation(s)
- Woochul Nam
- University of Michigan, Ann Arbor, Michigan 48109-2125, United States of America
| | - Bogdan I Epureanu
- University of Michigan, Ann Arbor, Michigan 48109-2125, United States of America
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12
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Folding and assembly of the large molecular machine Hsp90 studied in single-molecule experiments. Proc Natl Acad Sci U S A 2016; 113:1232-7. [PMID: 26787848 DOI: 10.1073/pnas.1518827113] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Folding of small proteins often occurs in a two-state manner and is well understood both experimentally and theoretically. However, many proteins are much larger and often populate misfolded states, complicating their folding process significantly. Here we study the complete folding and assembly process of the 1,418 amino acid, dimeric chaperone Hsp90 using single-molecule optical tweezers. Although the isolated C-terminal domain shows two-state folding, we find that the isolated N-terminal as well as the middle domain populate ensembles of fast-forming, misfolded states. These intradomain misfolds slow down folding by an order of magnitude. Modeling folding as a competition between productive and misfolding pathways allows us to fully describe the folding kinetics. Beyond intradomain misfolding, folding of the full-length protein is further slowed by the formation of interdomain misfolds, suggesting that with growing chain lengths, such misfolds will dominate folding kinetics. Interestingly, we find that small stretching forces applied to the chain can accelerate folding by preventing the formation of cross-domain misfolding intermediates by leading the protein along productive pathways to the native state. The same effect is achieved by cotranslational folding at the ribosome in vivo.
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13
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Zhang P, Rayment I, Gilbert SP. Fast or Slow, Either Head Can Start the Processive Run of Kinesin-2 KIF3AC. J Biol Chem 2015; 291:4407-16. [PMID: 26710851 DOI: 10.1074/jbc.m115.705970] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Indexed: 11/06/2022] Open
Abstract
Mammalian KIF3AC contains two distinct motor polypeptides and is best known for its role in organelle transport in neurons. Our recent studies showed that KIF3AC is as processive as conventional kinesin-1, suggesting that their ATPase mechanochemistry may be similar. However, the presence of two different motor polypeptides in KIF3AC implies that there must be a cellular advantage for the KIF3AC heterodimer. The hypothesis tested was whether there is an intrinsic bias within KIF3AC such that either KIF3A or KIF3C initiates the processive run. To pursue these experiments, a mechanistic approach was used to compare the pre-steady-state kinetics of KIF3AC to the kinetics of homodimeric KIF3AA and KIF3CC. The results indicate that microtubule collision at 11.4 μM(-1) s(-1) coupled with ADP release at 78 s(-1) are fast steps for homodimeric KIF3AA. In contrast, KIF3CC exhibits much slower microtubule association at 2.1 μM(-1) s(-1) and ADP release at 8 s(-1). For KIF3AC, microtubule association at 6.6 μM(-1) s(-1) and ADP release at 51 s(-1) are intermediate between the constants for KIF3AA and KIF3CC. These results indicate that either KIF3A or KIF3C can initiate the processive run. Surprisingly, the kinetics of the initial event of microtubule collision followed by ADP release for KIF3AC is not equivalent to 1:1 mixtures of KIF3AA plus KIF3CC homodimers at the same motor concentration. These results reveal that the intermolecular communication within the KIF3AC heterodimer modulates entry into the processive run regardless of whether the run is initiated by the KIF3A or KIF3C motor domain.
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Affiliation(s)
- Pengwei Zhang
- From the Department of Biological Sciences and the Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180 and
| | - Ivan Rayment
- the Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706
| | - Susan P Gilbert
- From the Department of Biological Sciences and the Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180 and
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14
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Hierarchical cascades of instability govern the mechanics of coiled coils: helix unfolding precedes coil unzipping. Biophys J 2015; 107:477-484. [PMID: 25028889 DOI: 10.1016/j.bpj.2014.06.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 05/13/2014] [Accepted: 06/03/2014] [Indexed: 12/31/2022] Open
Abstract
Coiled coils are a fundamental emergent motif in proteins found in structural biomaterials, consisting of α-helical secondary structures wrapped in a supercoil. A fundamental question regarding the thermal and mechanical stability of coiled coils in extreme environments is the sequence of events leading to the disassembly of individual oligomers from the universal coiled-coil motifs. To shed light on this phenomenon, here we report atomistic simulations of a trimeric coiled coil in an explicit water solvent and investigate the mechanisms underlying helix unfolding and coil unzipping in the assembly. We employ advanced sampling techniques involving steered molecular dynamics and metadynamics simulations to obtain the free-energy landscapes of single-strand unfolding and unzipping in a three-stranded assembly. Our comparative analysis of the free-energy landscapes of instability pathways shows that coil unzipping is a sequential process involving multiple intermediates. At each intermediate state, one heptad repeat of the coiled coil first unfolds and then unzips due to the loss of contacts with the hydrophobic core. This observation suggests that helix unfolding facilitates the initiation of coiled-coil disassembly, which is confirmed by our 2D metadynamics simulations showing that unzipping of one strand requires less energy in the unfolded state compared with the folded state. Our results explain recent experimental findings and lay the groundwork for studying the hierarchical molecular mechanisms that underpin the thermomechanical stability/instability of coiled coils and similar protein assemblies.
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15
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Liu J, Yang J, Wen J, Yang Y, Wei X, Zhang X, Wang YP. Mutational analysis of dimeric linkers in peri- and cytoplasmic domains of histidine kinase DctB reveals their functional roles in signal transduction. Open Biol 2015; 4:140023. [PMID: 24898140 PMCID: PMC4077058 DOI: 10.1098/rsob.140023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Membrane-associated histidine kinases (HKs) in two-component systems respond to environmental stimuli by autophosphorylation and phospho-transfer. HK typically contains a periplasmic sensor domain that regulates the cytoplasmic kinase domain through a conserved cytoplasmic linker. How signal is transduced from the ligand-binding site across the membrane barrier remains unclear. Here, we analyse two linker regions of a typical HK, DctB. One region connects the first transmembrane helix with the periplasmic Per-ARNT-Sim domains, while the other one connects the second transmembrane helix with the cytoplasmic kinase domains. We identify a leucine residue in the first linker region to be essential for the signal transduction and for maintaining the delicate balance of the dimeric interface, which is key to its activities. We also show that the other linker, belonging to the S-helix coiled-coil family, plays essential roles in signal transduction inside the cell. Furthermore, by combining mutations with opposing activities in the two regions, we show that these two signalling transduction elements are integrated to produce a combined effect on the final activity of DctB.
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Affiliation(s)
- Jiwei Liu
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Jianguo Yang
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Jin Wen
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Yun Yang
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Xiaolu Wei
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Xiaodong Zhang
- Department of Life Sciences, Centre for Structural Biology, Imperial College London, London SW7 2AZ, UK
| | - Yi-Ping Wang
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, People's Republic of China
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16
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Li Q, Scholl ZN, Marszalek PE. Capturing the Mechanical Unfolding Pathway of a Large Protein with Coiled-Coil Probes. Angew Chem Int Ed Engl 2014; 53:13429-33. [DOI: 10.1002/anie.201407211] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 09/10/2014] [Indexed: 11/08/2022]
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17
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Li Q, Scholl ZN, Marszalek PE. Capturing the Mechanical Unfolding Pathway of a Large Protein with Coiled-Coil Probes. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201407211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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18
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Lumme C, Altan-Martin H, Dastvan R, Sommer MS, Oreb M, Schuetz D, Hellenkamp B, Mirus O, Kretschmer J, Lyubenova S, Kügel W, Medelnik JP, Dehmer M, Michaelis J, Prisner TF, Hugel T, Schleiff E. Nucleotides and substrates trigger the dynamics of the Toc34 GTPase homodimer involved in chloroplast preprotein translocation. Structure 2014; 22:526-38. [PMID: 24631462 DOI: 10.1016/j.str.2014.02.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 01/29/2014] [Accepted: 02/01/2014] [Indexed: 12/13/2022]
Abstract
GTPases are molecular switches that control numerous crucial cellular processes. Unlike bona fide GTPases, which are regulated by intramolecular structural transitions, the less well studied GAD-GTPases are activated by nucleotide-dependent dimerization. A member of this family is the translocase of the outer envelope membrane of chloroplast Toc34 involved in regulation of preprotein import. The GTPase cycle of Toc34 is considered a major circuit of translocation regulation. Contrary to expectations, previous studies yielded only marginal structural changes of dimeric Toc34 in response to different nucleotide loads. Referencing PELDOR and FRET single-molecule and bulk experiments, we describe a nucleotide-dependent transition of the dimer flexibility from a tight GDP- to a flexible GTP-loaded state. Substrate binding induces an opening of the GDP-loaded dimer. Thus, the structural dynamics of bona fide GTPases induced by GTP hydrolysis is replaced by substrate-dependent dimer flexibility, which likely represents a general regulatory mode for dimerizing GTPases.
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Affiliation(s)
- Christina Lumme
- Physics Department E22 and IMETUM, Technical University Munich, 85748 Garching, Germany
| | - Hasret Altan-Martin
- Institute of Molecular Cell Biology of Plants, Goethe University, 60438 Frankfurt, Germany
| | - Reza Dastvan
- Institute of Physical and Theoretical Chemistry, Goethe University, 60438 Frankfurt, Germany; Cluster of Excellence "Macromolecular Complexes", Goethe University, 60438 Frankfurt, Germany; Center for Biomolecular Magnetic Resonance, Goethe University, 60438 Frankfurt, Germany; Department of Molecular Physiology & Biophysics, Vanderbilt University, 741 Light Hall, 2215 Garland Avenue, Nashville, TN 37232, USA
| | - Maik S Sommer
- Institute of Molecular Cell Biology of Plants, Goethe University, 60438 Frankfurt, Germany
| | - Mislav Oreb
- Physics Department E22 and IMETUM, Technical University Munich, 85748 Garching, Germany
| | - Denise Schuetz
- Institute of Physical and Theoretical Chemistry, Goethe University, 60438 Frankfurt, Germany; Cluster of Excellence "Macromolecular Complexes", Goethe University, 60438 Frankfurt, Germany; Center for Biomolecular Magnetic Resonance, Goethe University, 60438 Frankfurt, Germany
| | - Björn Hellenkamp
- Physics Department E22 and IMETUM, Technical University Munich, 85748 Garching, Germany
| | - Oliver Mirus
- Institute of Molecular Cell Biology of Plants, Goethe University, 60438 Frankfurt, Germany
| | - Jens Kretschmer
- Institute of Molecular Cell Biology of Plants, Goethe University, 60438 Frankfurt, Germany
| | - Sevdalina Lyubenova
- Institute of Physical and Theoretical Chemistry, Goethe University, 60438 Frankfurt, Germany; Cluster of Excellence "Macromolecular Complexes", Goethe University, 60438 Frankfurt, Germany; Center for Biomolecular Magnetic Resonance, Goethe University, 60438 Frankfurt, Germany
| | | | - Jan P Medelnik
- Institute of Molecular Cell Biology of Plants, Goethe University, 60438 Frankfurt, Germany
| | - Manuela Dehmer
- Institute of Molecular Cell Biology of Plants, Goethe University, 60438 Frankfurt, Germany
| | | | - Thomas F Prisner
- Institute of Physical and Theoretical Chemistry, Goethe University, 60438 Frankfurt, Germany; Cluster of Excellence "Macromolecular Complexes", Goethe University, 60438 Frankfurt, Germany; Center for Biomolecular Magnetic Resonance, Goethe University, 60438 Frankfurt, Germany
| | - Thorsten Hugel
- Physics Department E22 and IMETUM, Technical University Munich, 85748 Garching, Germany
| | - Enrico Schleiff
- Institute of Molecular Cell Biology of Plants, Goethe University, 60438 Frankfurt, Germany; Cluster of Excellence "Macromolecular Complexes", Goethe University, 60438 Frankfurt, Germany; Center for Membrane Proteomics, Goethe University, 60438 Frankfurt, Germany.
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19
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Affiliation(s)
- Tie Xia
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Key Laboratory of Molecular Nanostructures and Nanotechnology, Chinese Academy of Sciences, Beijing 100190, China;
| | - Nan Li
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Key Laboratory of Molecular Nanostructures and Nanotechnology, Chinese Academy of Sciences, Beijing 100190, China;
| | - Xiaohong Fang
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Key Laboratory of Molecular Nanostructures and Nanotechnology, Chinese Academy of Sciences, Beijing 100190, China;
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20
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The how’s and why’s of protein folding intermediates. Arch Biochem Biophys 2013; 531:14-23. [DOI: 10.1016/j.abb.2012.10.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 10/05/2012] [Accepted: 10/11/2012] [Indexed: 12/13/2022]
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21
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22
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Eckert T, Le DTV, Link S, Friedmann L, Woehlke G. Spastin's microtubule-binding properties and comparison to katanin. PLoS One 2012; 7:e50161. [PMID: 23272056 PMCID: PMC3521757 DOI: 10.1371/journal.pone.0050161] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 10/17/2012] [Indexed: 11/19/2022] Open
Abstract
Spastin and katanin are ring-shaped hexameric AAA ATPases that sever microtubules, and thus crucially depend on a physical interaction with microtubules. For the first time, we report here the microtubule binding properties of spastin at the single-molecule level, and compare them to katanin. Microscopic fluorescence assays showed that human spastin bound to microtubules by ionic interactions, and diffused along microtubules with a diffusion coefficient comparable to katanin. The microscopic measurement of landing and dissociation rates demonstrated the ionic character of the interaction, which could be mapped to a patch of three lysine residues outside of the catalytic domain of human spastin. This motif is not conserved in Drosophila spastin or katanin, which also bound by non-catalytic parts of the protein. The binding affinities of spastin and katanin were nucleotide-sensitive, with the lowest affinities under ADP,, the highest under ATP-γS conditions. These changes correlated with the formation of higher oligomeric states, as shown in biochemical experiments and electron microscopic images. Vice versa, the artificial dimerization of human spastin by addition of a coiled coil led to a constitutively active enzyme. These observations suggest that dimer formation is a crucial step in the formation of the active complex, and thus the severing process by spastin.
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Affiliation(s)
| | | | | | | | - Günther Woehlke
- Department of Physics E22 (Biophysics), Technische Universität München, Garching, Germany
- * E-mail:
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23
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Doodhi H, Jana SC, Devan P, Mazumdar S, Ray K. Biochemical and molecular dynamic simulation analysis of a weak coiled coil association between kinesin-II stalks. PLoS One 2012; 7:e45981. [PMID: 23029351 PMCID: PMC3461054 DOI: 10.1371/journal.pone.0045981] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 08/27/2012] [Indexed: 01/03/2023] Open
Abstract
DEFINITION Kinesin-2 refers to the family of motor proteins represented by conserved, heterotrimeric kinesin-II and homodimeric Osm3/Kif17 class of motors. BACKGROUND Kinesin-II, a microtubule-based anterograde motor, is composed of three different conserved subunits, named KLP64D, KLP68D and DmKAP in Drosophila. Although previous reports indicated that coiled coil interaction between the middle segments of two dissimilar motor subunits established the heterodimer, the molecular basis of the association is still unknown. METHODOLOGY/PRINCIPAL FINDINGS Here, we present a detailed heterodimeric association model of the KLP64D/68D stalk supported by extensive experimental analysis and molecular dynamic simulations. We find that KLP64D stalk is unstable, but forms a weak coiled coil heteroduplex with the KLP68D stalk when coexpressed in bacteria. Local instabilities, relative affinities between the C-terminal stalk segments, and dynamic long-range interactions along the stalks specify the heterodimerization. Thermal unfolding studies and independent simulations further suggest that interactions between the C-terminal stalk fragments are comparatively stable, whereas the N-terminal stalk reversibly unfolds at ambient temperature. CONCLUSIONS/SIGNIFICANCE Results obtained in this study suggest that coiled coil interaction between the C-terminal stalks of kinesin-II motor subunits is held together through a few hydrophobic and charged interactions. The N-terminal stalk segments are flexible and could uncoil reversibly during a motor walk. This supports the requirement for a flexible coiled coil association between the motor subunits, and its role in motor function needs to be elucidated.
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Affiliation(s)
- Harinath Doodhi
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Swadhin C. Jana
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Pavithra Devan
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Shyamalava Mazumdar
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Krishanu Ray
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
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24
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Chelli R. Local Sampling in Steered Monte Carlo Simulations Decreases Dissipation and Enhances Free Energy Estimates via Nonequilibrium Work Theorems. J Chem Theory Comput 2012; 8:4040-52. [DOI: 10.1021/ct300348w] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Riccardo Chelli
- Dipartimento di Chimica,
Università di Firenze,
Via della Lastruccia 3, I-50019 Sesto Fiorentino, Italy
- European Laboratory for Nonlinear Spectroscopy (LENS),
Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy
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25
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Affiliation(s)
- Charles E. Sing
- Department
of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139,
United States
| | - Alfredo Alexander-Katz
- Department
of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139,
United States
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26
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Lin CY, Huang JY, Lo LW. Dynamic regulation on energy landscape evolution of single-molecule protein by conformational fluctuation. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 86:021925. [PMID: 23005803 DOI: 10.1103/physreve.86.021925] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Indexed: 06/01/2023]
Abstract
We formalize a theory to help explore the effect of conformational fluctuation on the energy landscape evolution of single-molecule protein. Using this formalization, we investigate the photon emission from single photoactivated fluorescent protein. A bimodal regulation on the energy landscape evolution was discovered, and its origin was attributed to slow conformational fluctuations of the protein matrix.
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Affiliation(s)
- Chien Y Lin
- Department of Photonics and Institute of Electro-Optical Engineering, Chiao Tung University, Hsinchu 300, Taiwan, Republic of China
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27
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Ponmurugan M, Vemparala S. Studies on structural and average unfolding behaviours of FNIII domain of Contactin-1 protein by molecular dynamics simulation. FRONTIERS IN LIFE SCIENCE 2012. [DOI: 10.1080/21553769.2013.776995] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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28
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Are coiled-coils of dimeric kinesins unwound during their walking on microtubule? PLoS One 2012; 7:e36071. [PMID: 22558333 PMCID: PMC3338639 DOI: 10.1371/journal.pone.0036071] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 03/22/2012] [Indexed: 11/22/2022] Open
Abstract
Dimeric kinesin motor proteins such as homodimeric kinesin-1, homodimeric Ncd and heterodimeric Kar3/Vik1are composed of two head domains which are connected together by a rod-shaped, coiled-coil stalk. Despite the extensive and intensive studies on structures, kinetics, dynamics and walking mechanism of the dimers, whether their coiled-coils are unwound or not during their walking on the microtubule is still an unclear issue. Here, we try to clarify this issue by using molecular dynamics simulations. Our simulation results showed that, for Ncd, a large change in potential of mean force is required to unwind the coiled-coil by only several pairs of residues. For both Ncd and kinesin-1, the force required to initiate the coiled-coil unwinding is larger than that required for unfolding of the single -helix that forms the coiled-coil or is larger than that required to unwind the DNA duplex, which is higher than the unbinding force of the kinesin head from the microtubule in strong microtubule-binding states. Based on these results and the comparison of the sequence between the coiled-coil of Kar3/Vik1 and those of Ncd and kinesin-1, it was deduced that the coiled-coil of the Kar3/Vik1 should also be very stable. Thus, we concluded that the coiled-coils of kinesin-1, Ncd and Kar3/Vik1 are almost impossible to unwind during their walking on the microtubule.
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29
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Hoffmann T, Dougan L. Single molecule force spectroscopy using polyproteins. Chem Soc Rev 2012; 41:4781-96. [DOI: 10.1039/c2cs35033e] [Citation(s) in RCA: 139] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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30
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Gao Y, Sirinakis G, Zhang Y. Highly anisotropic stability and folding kinetics of a single coiled coil protein under mechanical tension. J Am Chem Soc 2011; 133:12749-57. [PMID: 21707065 DOI: 10.1021/ja204005r] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Coiled coils are one of the most abundant protein structural motifs and widely mediate protein interactions and force transduction or sensation. They are thus model systems for protein engineering and folding studies, particularly the GCN4 coiled coil. Major single-molecule methods have also been applied to this protein and revealed its folding kinetics at various spatiotemporal scales. Nevertheless, the folding energy and the kinetics of a single GCN4 coiled coil domain have not been well determined at a single-molecule level. Here we used high-resolution optical tweezers to characterize the folding and unfolding reactions of a single GCN4 coiled coil domain and their dependence on the pulling direction. In one axial and two transverse pulling directions, we observed reversible, two-state transitions of the coiled coil in real time. The transitions equilibrate at pulling forces ranging from 6 to 12 pN, showing different stabilities of the coiled coil in regard to pulling direction. Furthermore, the transition rates vary with both the magnitude and the direction of the pulling force by greater than 1000 folds, indicating a highly anisotropic and topology-dependent energy landscape for protein transitions under mechanical tension. We developed a new analytical theory to extract energy and kinetics of the protein transition at zero force. The derived folding energy does not depend on the pulling direction and is consistent with the measurement in bulk, which further confirms the applicability of the single-molecule manipulation approach for energy measurement. The highly anisotropic thermodynamics of proteins under tension should play important roles in their biological functions.
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Affiliation(s)
- Ying Gao
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, United States
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31
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Veigel C, Schmidt CF. Moving into the cell: single-molecule studies of molecular motors in complex environments. Nat Rev Mol Cell Biol 2011; 12:163-76. [PMID: 21326200 DOI: 10.1038/nrm3062] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Much has been learned in the past decades about molecular force generation. Single-molecule techniques, such as atomic force microscopy, single-molecule fluorescence microscopy and optical tweezers, have been key in resolving the mechanisms behind the power strokes, 'processive' steps and forces of cytoskeletal motors. However, it remains unclear how single force generators are integrated into composite mechanical machines in cells to generate complex functions such as mitosis, locomotion, intracellular transport or mechanical sensory transduction. Using dynamic single-molecule techniques to track, manipulate and probe cytoskeletal motor proteins will be crucial in providing new insights.
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Affiliation(s)
- Claudia Veigel
- Department of Cellular Physiology, Institute of Physiology, Ludwig-Maximilians-Universität München, Schillerstrasse 44, 80336 München, Germany.
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32
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Nicolini P, Frezzato D, Chelli R. Exploiting Configurational Freezing in Nonequilibrium Monte Carlo Simulations. J Chem Theory Comput 2011; 7:582-93. [DOI: 10.1021/ct100568n] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Paolo Nicolini
- Dipartimento di Chimica, Università di Firenze, Via della Lastruccia 3, I-50019 Sesto Fiorentino, Italy
| | - Diego Frezzato
- Dipartimento di Scienze Chimiche, Università di Padova, Via Marzolo 1, I-35131 Padova, Italy
| | - Riccardo Chelli
- Dipartimento di Chimica, Università di Firenze, Via della Lastruccia 3, I-50019 Sesto Fiorentino, Italy
- European Laboratory for Nonlinear Spectroscopy (LENS), Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy
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33
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Kim M, Abdi K, Lee G, Rabbi M, Lee W, Yang M, Schofield CJ, Bennett V, Marszalek PE. Fast and forceful refolding of stretched alpha-helical solenoid proteins. Biophys J 2010; 98:3086-92. [PMID: 20550922 DOI: 10.1016/j.bpj.2010.02.054] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2009] [Revised: 02/10/2010] [Accepted: 02/26/2010] [Indexed: 01/23/2023] Open
Abstract
Anfinsen's thermodynamic hypothesis implies that proteins can encode for stretching through reversible loss of structure. However, large in vitro extensions of proteins that occur through a progressive unfolding of their domains typically dissipate a significant amount of energy, and therefore are not thermodynamically reversible. Some coiled-coil proteins have been found to stretch nearly reversibly, although their extension is typically limited to 2.5 times their folded length. Here, we report investigations on the mechanical properties of individual molecules of ankyrin-R, beta-catenin, and clathrin, which are representative examples of over 800 predicted human proteins composed of tightly packed alpha-helical repeats (termed ANK, ARM, or HEAT repeats, respectively) that form spiral-shaped protein domains. Using atomic force spectroscopy, we find that these polypeptides possess unprecedented stretch ratios on the order of 10-15, exceeding that of other proteins studied so far, and their extension and relaxation occurs with minimal energy dissipation. Their sequence-encoded elasticity is governed by stepwise unfolding of small repeats, which upon relaxation of the stretching force rapidly and forcefully refold, minimizing the hysteresis between the stretching and relaxing parts of the cycle. Thus, we identify a new class of proteins that behave as highly reversible nanosprings that have the potential to function as mechanosensors in cells and as building blocks in springy nanostructures. Our physical view of the protein component of cells as being comprised of predominantly inextensible structural elements under tension may need revision to incorporate springs.
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Affiliation(s)
- Minkyu Kim
- Department of Mechanical Engineering and Materials Science, Center for Biologically Inspired Materials and Material Systems, Duke University, Durham, North Carolina, USA
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34
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Baclayon M, Roos WH, Wuite GJL. Sampling protein form and function with the atomic force microscope. Mol Cell Proteomics 2010; 9:1678-88. [PMID: 20562411 PMCID: PMC2938060 DOI: 10.1074/mcp.r110.001461] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Indexed: 12/17/2022] Open
Abstract
To study the structure, function, and interactions of proteins, a plethora of techniques is available. Many techniques sample such parameters in non-physiological environments (e.g. in air, ice, or vacuum). Atomic force microscopy (AFM), however, is a powerful biophysical technique that can probe these parameters under physiological buffer conditions. With the atomic force microscope operating under such conditions, it is possible to obtain images of biological structures without requiring labeling and to follow dynamic processes in real time. Furthermore, by operating in force spectroscopy mode, it can probe intramolecular interactions and binding strengths. In structural biology, it has proven its ability to image proteins and protein conformational changes at submolecular resolution, and in proteomics, it is developing as a tool to map surface proteomes and to study protein function by force spectroscopy methods. The power of AFM to combine studies of protein form and protein function enables bridging various research fields to come to a comprehensive, molecular level picture of biological processes. We review the use of AFM imaging and force spectroscopy techniques and discuss the major advances of these experiments in further understanding form and function of proteins at the nanoscale in physiologically relevant environments.
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Affiliation(s)
- Marian Baclayon
- From the Natuur- en Sterrenkunde and Lasercentrum, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Wouter H. Roos
- From the Natuur- en Sterrenkunde and Lasercentrum, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Gijs J. L. Wuite
- From the Natuur- en Sterrenkunde and Lasercentrum, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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35
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Nicolini P, Procacci P, Chelli R. Hummer and Szabo-like Potential of Mean Force Estimator for Bidirectional Nonequilibrium Pulling Experiments/Simulations. J Phys Chem B 2010; 114:9546-54. [DOI: 10.1021/jp102263y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Paolo Nicolini
- Dipartimento di Chimica, Università di Firenze, Via della Lastruccia 3, I-50019 Sesto Fiorentino, Italy, European Laboratory for Nonlinear Spectroscopy (LENS), Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy, and Centro Interdipartimentale per lo Studio delle Dinamiche Complesse (CSDC), Via Sansone 1, I-50019 Sesto Fiorentino, Italy
| | - Piero Procacci
- Dipartimento di Chimica, Università di Firenze, Via della Lastruccia 3, I-50019 Sesto Fiorentino, Italy, European Laboratory for Nonlinear Spectroscopy (LENS), Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy, and Centro Interdipartimentale per lo Studio delle Dinamiche Complesse (CSDC), Via Sansone 1, I-50019 Sesto Fiorentino, Italy
| | - Riccardo Chelli
- Dipartimento di Chimica, Università di Firenze, Via della Lastruccia 3, I-50019 Sesto Fiorentino, Italy, European Laboratory for Nonlinear Spectroscopy (LENS), Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy, and Centro Interdipartimentale per lo Studio delle Dinamiche Complesse (CSDC), Via Sansone 1, I-50019 Sesto Fiorentino, Italy
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36
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Unravelling the design principles for single protein mechanical strength. Curr Opin Struct Biol 2010; 20:508-17. [PMID: 20542682 DOI: 10.1016/j.sbi.2010.05.005] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Revised: 04/29/2010] [Accepted: 05/04/2010] [Indexed: 01/04/2023]
Abstract
In recent years single molecule manipulation techniques have improved to the extent that measurements of the mechanical strength of single proteins can now be undertaken routinely. This powerful new tool, coupled with theoretical frameworks to characterise the unfolding process, has enabled significant progress to be made in understanding the physical mechanisms that underlie protein mechanical strength. These design concepts have allowed the search for proteins with novel, mechanically strong folds to be automated and for previously mechanically characterised proteins to be engineered rationally. Methods to achieve the latter are diverse and include re-engineering of specific hydrophobic core residues, changing solvent conditions and the 'cross-linking' of side-chains that are separated in the rate-limiting unfolding transition. Predicting the mechanical behaviour of larger proteins and those with more complex structures remains a significant challenge while on-going instrument development is beginning to allow the examination of mechanical strength of protein across a wide range of force loading rates. The integral role of force in biology and the potential for exploitation of catalytic and structural proteins as functional bio-materials makes this a particularly important area of research.
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37
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Bornschlögl T, Gebhardt JCM, Rief M. Designing the folding mechanics of coiled coils. Chemphyschem 2010; 10:2800-4. [PMID: 19746505 DOI: 10.1002/cphc.200900575] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Naturally occurring coiled coils are often not homogeneous throughout their entire structure but rather interrupted by sequence discontinuities and non-coiled-coil-forming subsegments. We apply atomic force microscopy to locally probe the mechanical folding/unfolding process of a well-understood model coiled coil when unstructured subsegments with different sizes are added. We find that the refolding force decreases from 7.8 pN with increasing size of the added unstructured subsegment, while the unfolding properties of the model coiled coil remain unchanged. We show that this behavior results from the increased size of the nucleation seed which has to form before further coiled-coil folding can proceed. Since the nucleation seed size is linked to the width of the energetic folding barrier, we are able to directly measure the dependence of folding forces on the barrier width. Our results allow the design of coiled coils with designated refolding forces by simply adjusting the nucleation seed size.
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Affiliation(s)
- Thomas Bornschlögl
- Physik Department E22, Technische Universität München, James Franck Strasse, 85748 Garching, Germany.
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38
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Marsili S, Procacci P. Free Energy Reconstruction in Bidirectional Force Spectroscopy Experiments: The Effect of the Device Stiffness. J Phys Chem B 2010; 114:2509-16. [DOI: 10.1021/jp908663z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Simone Marsili
- Dipartimento di Chimica, Universita di Firenze, Via della Lastruccia 3, I-50019 Sesto Fiorentino, Italy, and Centro Interdipartimentale per lo Studio delle Dinamiche Complesse (CSDC),Via Sansone 1, I-50019 Sesto Fiorentino, Italy
| | - Piero Procacci
- Dipartimento di Chimica, Universita di Firenze, Via della Lastruccia 3, I-50019 Sesto Fiorentino, Italy, and Centro Interdipartimentale per lo Studio delle Dinamiche Complesse (CSDC),Via Sansone 1, I-50019 Sesto Fiorentino, Italy
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39
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Full distance-resolved folding energy landscape of one single protein molecule. Proc Natl Acad Sci U S A 2010; 107:2013-8. [PMID: 20133846 DOI: 10.1073/pnas.0909854107] [Citation(s) in RCA: 171] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Kinetic bulk and single molecule folding experiments characterize barrier properties but the shape of folding landscapes between barrier top and native state is difficult to access. Here, we directly extract the full free energy landscape of a single molecule of the GCN4 leucine zipper using dual beam optical tweezers. To this end, we use deconvolution force spectroscopy to follow an individual molecule's trajectory with high temporal and spatial resolution. We find a heterogeneous energy landscape of the GCN4 leucine zipper domain. The energy profile is divided into two stable C-terminal heptad repeats and two less stable repeats at the N-terminus. Energies and transition barrier positions were confirmed by single molecule kinetic analysis. We anticipate that deconvolution sampling is a powerful tool for the model-free investigation of protein energy landscapes.
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Sadeghi S, Emberly E. Length-dependent force characteristics of coiled coils. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 80:061909. [PMID: 20365192 DOI: 10.1103/physreve.80.061909] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Indexed: 05/29/2023]
Abstract
Coiled-coil domains within and between proteins play important structural roles in biology. They consist of two or more alpha helices that form a superhelical structure due to packing of the hydrophobic residues that pattern each helix. A recent continuum model showed that the correspondence between the chirality of the pack to that of the underlying hydrophobic pattern comes about because of the internal deformation energy associated with each helix in forming the superhelix. We have developed a coarse-grained atomistic model for coiled coils that includes the competition between the hydrophobic energy that drives folding and the cost due to deforming each helix. The model exhibits a structural transition from a non-coiled-coil to coiled-coil state as the contribution from the deformation energy changes. Our model is able to reproduce naturally occurring coiled coils and essential features seen in unzipping experiments. We explore the force-extension properties of these model coiled coils as a function helix length and find that shorter coils unfold at lower force than longer ones with the required unfolding force eventually becoming length independent.
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Affiliation(s)
- Sara Sadeghi
- Physics Department, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
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