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Mukadum F, Ccoa WJP, Hocky GM. Molecular simulation approaches to probing the effects of mechanical forces in the actin cytoskeleton. Cytoskeleton (Hoboken) 2024; 81:318-327. [PMID: 38334204 PMCID: PMC11310368 DOI: 10.1002/cm.21837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 02/10/2024]
Abstract
In this article we give our perspective on the successes and promise of various molecular and coarse-grained simulation approaches to probing the effect of mechanical forces in the actin cytoskeleton.
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Affiliation(s)
- Fatemah Mukadum
- Department of Chemistry, New York University, New York, NY 10003, USA
| | | | - Glen M. Hocky
- Department of Chemistry, New York University, New York, NY 10003, USA
- Simons Center for Computational Physical Chemistry, New York, NY 10003, USA
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2
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Wang Y, Wu J, Zsolnay V, Pollard TD, Voth GA. Mechanism of phosphate release from actin filaments. Proc Natl Acad Sci U S A 2024; 121:e2408156121. [PMID: 38980907 PMCID: PMC11260136 DOI: 10.1073/pnas.2408156121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Accepted: 06/10/2024] [Indexed: 07/11/2024] Open
Abstract
After ATP-actin monomers assemble filaments, the ATP's [Formula: see text]-phosphate is hydrolyzedwithin seconds and dissociates over minutes. We used all-atom molecular dynamics simulations to sample the release of phosphate from filaments and study residues that gate release. Dissociation of phosphate from Mg2+ is rate limiting and associated with an energy barrier of 20 kcal/mol, consistent with experimental rates of phosphate release. Phosphate then diffuses within an internal cavity toward a gate formed by R177, as suggested in prior computational studies and cryo-EM structures. The gate is closed when R177 hydrogen bonds with N111 and is open when R177 forms a salt bridge with D179. Most of the time, interactions of R177 with other residues occlude the phosphate release pathway. Machine learning analysis reveals that the occluding interactions fluctuate rapidly, underscoring the secondary role of backdoor gate opening in Pi release, in contrast with the previous hypothesis that gate opening is the primary event.
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Affiliation(s)
- Yihang Wang
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics and James Frank Institute, University of Chicago, Chicago, IL60637
| | - Jiangbo Wu
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics and James Frank Institute, University of Chicago, Chicago, IL60637
| | - Vilmos Zsolnay
- Graduate Program in Biophysical Sciences, University of Chicago, Chicago, IL60637
| | - Thomas D. Pollard
- Department of Molecular Cellular and Developmental Biology, Yale University, New Haven, CT06511
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT06511
- Department of Cell Biology, Yale University, New Haven, CT06510
| | - Gregory A. Voth
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics and James Frank Institute, University of Chicago, Chicago, IL60637
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3
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Niedzialkowska E, Runyan LA, Kudryashova E, Egelman EH, Kudryashov DS. Stabilization of F-actin by Salmonella effector SipA resembles the structural effects of inorganic phosphate and phalloidin. Structure 2024; 32:725-738.e8. [PMID: 38518780 PMCID: PMC11162321 DOI: 10.1016/j.str.2024.02.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/08/2024] [Accepted: 02/26/2024] [Indexed: 03/24/2024]
Abstract
Entry of Salmonella into host enterocytes relies on its pathogenicity island 1 effector SipA. We found that SipA binds to F-actin in a 1:2 stoichiometry with sub-nanomolar affinity. A cryo-EM reconstruction revealed that SipA's globular core binds at the groove between actin strands, whereas the extended C-terminal arm penetrates deeply into the inter-strand space, stabilizing F-actin from within. The unusually strong binding of SipA is achieved by a combination of fast association via the core and very slow dissociation dictated by the arm. Similar to Pi, BeF3, and phalloidin, SipA potently inhibited actin depolymerization by actin depolymerizing factor (ADF)/cofilin, which correlated with increased filament stiffness, supporting the hypothesis that F-actin's mechanical properties contribute to the recognition of its nucleotide state by protein partners. The remarkably strong binding to F-actin maximizes the toxin's effects at the injection site while minimizing global influence on the cytoskeleton and preventing pathogen detection by the host cell.
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Affiliation(s)
- Ewa Niedzialkowska
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22903, USA
| | - Lucas A Runyan
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Elena Kudryashova
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Edward H Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22903, USA.
| | - Dmitri S Kudryashov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.
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4
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Truong DT, Ho K, Pham DQH, Chwastyk M, Nguyen-Minh T, Nguyen MT. Treatment of flexibility of protein backbone in simulations of protein-ligand interactions using steered molecular dynamics. Sci Rep 2024; 14:10475. [PMID: 38714683 PMCID: PMC11076533 DOI: 10.1038/s41598-024-59899-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2024] [Accepted: 04/16/2024] [Indexed: 05/10/2024] Open
Abstract
To ensure that an external force can break the interaction between a protein and a ligand, the steered molecular dynamics simulation requires a harmonic restrained potential applied to the protein backbone. A usual practice is that all or a certain number of protein's heavy atoms or Cα atoms are fixed, being restrained by a small force. This present study reveals that while fixing both either all heavy atoms and or all Cα atoms is not a good approach, while fixing a too small number of few atoms sometimes cannot prevent the protein from rotating under the influence of the bulk water layer, and the pulled molecule may smack into the wall of the active site. We found that restraining the Cα atoms under certain conditions is more relevant. Thus, we would propose an alternative solution in which only the Cα atoms of the protein at a distance larger than 1.2 nm from the ligand are restrained. A more flexible, but not too flexible, protein will be expected to lead to a more natural release of the ligand.
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Affiliation(s)
- Duc Toan Truong
- Laboratory for Chemical Computation and Modeling, Institute for Computational Science and Artificial Intelligence, Van Lang University, Ho Chi Minh City, 70000, Vietnam
- Faculty of Applied Technology, School of Technology, Van Lang University, Ho Chi Minh City, 70000, Vietnam
| | - Kiet Ho
- Institute for Computational Science and Technology (ICST), Quang Trung Software City, Ho Chi Minh City, 70000, Vietnam
| | | | - Mateusz Chwastyk
- Institute of Physics, Polish Academy of Sciences, Warsaw, Poland
| | - Thai Nguyen-Minh
- University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City, 70000, Vietnam
| | - Minh Tho Nguyen
- Laboratory for Chemical Computation and Modeling, Institute for Computational Science and Artificial Intelligence, Van Lang University, Ho Chi Minh City, 70000, Vietnam.
- Faculty of Applied Technology, School of Technology, Van Lang University, Ho Chi Minh City, 70000, Vietnam.
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5
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Nong D, Haviland ZK, Zexer N, Pfaff SA, Cosgrove DJ, Tien M, Anderson CT, Hancock WO. Single-molecule tracking reveals dual front door/back door inhibition of Cel7A cellulase by its product cellobiose. Proc Natl Acad Sci U S A 2024; 121:e2322567121. [PMID: 38648472 PMCID: PMC11067010 DOI: 10.1073/pnas.2322567121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 03/18/2024] [Indexed: 04/25/2024] Open
Abstract
Degrading cellulose is a key step in the processing of lignocellulosic biomass into bioethanol. Cellobiose, the disaccharide product of cellulose degradation, has been shown to inhibit cellulase activity, but the mechanisms underlying product inhibition are not clear. We combined single-molecule imaging and biochemical investigations with the goal of revealing the mechanism by which cellobiose inhibits the activity of Trichoderma reesei Cel7A, a well-characterized exo-cellulase. We find that cellobiose slows the processive velocity of Cel7A and shortens the distance moved per encounter; effects that can be explained by cellobiose binding to the product release site of the enzyme. Cellobiose also strongly inhibits the binding of Cel7A to immobilized cellulose, with a Ki of 2.1 mM. The isolated catalytic domain (CD) of Cel7A was also inhibited to a similar degree by cellobiose, and binding of an isolated carbohydrate-binding module to cellulose was not inhibited by cellobiose, suggesting that cellobiose acts on the CD alone. Finally, cellopentaose inhibited Cel7A binding at micromolar concentrations without affecting the enzyme's velocity of movement along cellulose. Together, these results suggest that cellobiose inhibits Cel7A activity both by binding to the "back door" product release site to slow activity and to the "front door" substrate-binding tunnel to inhibit interaction with cellulose. These findings point to strategies for engineering cellulases to reduce product inhibition and enhance cellulose degradation, supporting the growth of a sustainable bioeconomy.
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Affiliation(s)
- Daguan Nong
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA16802
| | - Zachary K. Haviland
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA16802
| | - Nerya Zexer
- Department of Biology, Pennsylvania State University, University Park, PA16802
| | - Sarah A. Pfaff
- Department of Biology, Pennsylvania State University, University Park, PA16802
- Intercollege Graduate Degree Program in Plant Biology, Department of Biology, The Pennsylvania State University, University Park, PA16802
| | - Daniel J. Cosgrove
- Department of Biology, Pennsylvania State University, University Park, PA16802
| | - Ming Tien
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA16802
| | - Charles T. Anderson
- Department of Biology, Pennsylvania State University, University Park, PA16802
| | - William O. Hancock
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA16802
- Department of Chemistry, Pennsylvania State University, University Park, PA16802
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6
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Niedzialkowska E, Runyan LA, Kudryashova E, Egelman EH, Kudryashov DS. Stabilization of F-actin by Salmonella effector SipA resembles the structural effects of inorganic phosphate and phalloidin. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.26.573373. [PMID: 38234808 PMCID: PMC10793455 DOI: 10.1101/2023.12.26.573373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Entry of Salmonella into host enterocytes strictly relies on its pathogenicity island 1 effector SipA. We found that SipA binds to F-actin in a unique mode in a 1:2 stoichiometry with picomolar affinity. A cryo-EM reconstruction revealed that SipA's globular core binds at the grove between actin strands, whereas the extended C-terminal arm penetrates deeply into the inter-strand space, stabilizing F-actin from within. The unusually strong binding of SipA is achieved via a combination of fast association via the core and very slow dissociation dictated by the arm. Similarly to Pi, BeF3, and phalloidin, SipA potently inhibited actin depolymerization by ADF/cofilin, which correlated with the increased filament stiffness, supporting the hypothesis that F-actin's mechanical properties contribute to the recognition of its nucleotide state by protein partners. The remarkably strong binding to F-actin maximizes the toxin's effects at the injection site while minimizing global influence on the cytoskeleton and preventing pathogen detection by the host cell.
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Affiliation(s)
- Ewa Niedzialkowska
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22903, USA
| | - Lucas A. Runyan
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Elena Kudryashova
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Edward H. Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22903, USA
| | - Dmitri S. Kudryashov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
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7
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Oosterheert W, Blanc FEC, Roy A, Belyy A, Sanders MB, Hofnagel O, Hummer G, Bieling P, Raunser S. Molecular mechanisms of inorganic-phosphate release from the core and barbed end of actin filaments. Nat Struct Mol Biol 2023; 30:1774-1785. [PMID: 37749275 PMCID: PMC10643162 DOI: 10.1038/s41594-023-01101-9] [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] [Received: 04/07/2023] [Accepted: 08/18/2023] [Indexed: 09/27/2023]
Abstract
The release of inorganic phosphate (Pi) from actin filaments constitutes a key step in their regulated turnover, which is fundamental to many cellular functions. The mechanisms underlying Pi release from the core and barbed end of actin filaments remain unclear. Here, using human and bovine actin isoforms, we combine cryo-EM with molecular-dynamics simulations and in vitro reconstitution to demonstrate how actin releases Pi through a 'molecular backdoor'. While constantly open at the barbed end, the backdoor is predominantly closed in filament-core subunits and opens only transiently through concerted amino acid rearrangements. This explains why Pi escapes rapidly from the filament end but slowly from internal subunits. In a nemaline-myopathy-associated actin variant, the backdoor is predominantly open in filament-core subunits, resulting in accelerated Pi release and filaments with drastically shortened ADP-Pi caps. Our results provide the molecular basis for Pi release from actin and exemplify how a disease-linked mutation distorts the nucleotide-state distribution and atomic structure of the filament.
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Affiliation(s)
- Wout Oosterheert
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Florian E C Blanc
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Ankit Roy
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Alexander Belyy
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Micaela Boiero Sanders
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Oliver Hofnagel
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
- Institute for Biophysics, Goethe University, Frankfurt am Main, Germany.
| | - Peter Bieling
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany.
| | - Stefan Raunser
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany.
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8
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Steffensen KE, Dawson JF. Actin's C-terminus coordinates actin structural changes and functions. Cytoskeleton (Hoboken) 2023; 80:313-329. [PMID: 37036084 DOI: 10.1002/cm.21757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 03/17/2023] [Accepted: 03/30/2023] [Indexed: 04/11/2023]
Abstract
Actin is essential to eukaryotic cellular processes. Actin's C-terminus appears to play a direct role in modulating actin's structure and properties, facilitating the binding and function of actin-binding proteins (ABPs). The structural and functional characterization of filamentous actin's C-terminus has been impeded by its inherent flexibility, as well as actin's resistance to crystallization for x-ray diffraction and the historical resolution constraints associated with electron microscopy. Many biochemical studies have established that actin's C-terminus must retain its flexibility and structural integrity to modulate actin's structure and functions. For example, C-terminal structural changes are known to affect nucleotide binding and exchange, as well as propagate actin structural changes throughout extensive allosteric networks, facilitating the binding and function of ABPs. Advances in electron microscopy have resulted in high-resolution structures of filamentous actin, providing insights into subtle structural changes that are mediated by actin's C-terminus. Here, we review existing knowledge establishing the importance of actin's C-terminus within actin structural changes and functions and discuss how modern structural characterization techniques provide the tools to understand the role of actin's C-terminus in cellular processes.
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Affiliation(s)
- Karl E Steffensen
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - John F Dawson
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
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9
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Oosterheert W, Klink BU, Belyy A, Pospich S, Raunser S. Structural basis of actin filament assembly and aging. Nature 2022; 611:374-379. [DOI: 10.1038/s41586-022-05241-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 08/16/2022] [Indexed: 12/12/2022]
Abstract
AbstractThe dynamic turnover of actin filaments (F-actin) controls cellular motility in eukaryotes and is coupled to changes in the F-actin nucleotide state1–3. It remains unclear how F-actin hydrolyses ATP and subsequently undergoes subtle conformational rearrangements that ultimately lead to filament depolymerization by actin-binding proteins. Here we present cryo-electron microscopy structures of F-actin in all nucleotide states, polymerized in the presence of Mg2+ or Ca2+ at approximately 2.2 Å resolution. The structures show that actin polymerization induces the relocation of water molecules in the nucleotide-binding pocket, activating one of them for the nucleophilic attack of ATP. Unexpectedly, the back door for the subsequent release of inorganic phosphate (Pi) is closed in all structures, indicating that Pi release occurs transiently. The small changes in the nucleotide-binding pocket after ATP hydrolysis and Pi release are sensed by a key amino acid, amplified and transmitted to the filament periphery. Furthermore, differences in the positions of water molecules in the nucleotide-binding pocket explain why Ca2+-actin shows slower polymerization rates than Mg2+-actin. Our work elucidates the solvent-driven rearrangements that govern actin filament assembly and aging and lays the foundation for the rational design of drugs and small molecules for imaging and therapeutic applications.
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10
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Pepper I, Galkin VE. Actomyosin Complex. Subcell Biochem 2022; 99:421-470. [PMID: 36151385 PMCID: PMC9710302 DOI: 10.1007/978-3-031-00793-4_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Formation of cross-bridges between actin and myosin occurs ubiquitously in eukaryotic cells and mediates muscle contraction, intracellular cargo transport, and cytoskeletal remodeling. Myosin motors repeatedly bind to and dissociate from actin filaments in a cycle that transduces the chemical energy from ATP hydrolysis into mechanical force generation. While the general layout of surface elements within the actin-binding interface is conserved among myosin classes, sequence divergence within these motifs alters the specific contacts involved in the actomyosin interaction as well as the kinetics of mechanochemical cycle phases. Additionally, diverse lever arm structures influence the motility and force production of myosin molecules during their actin interactions. The structural differences generated by myosin's molecular evolution have fine-tuned the kinetics of its isoforms and adapted them for their individual cellular roles. In this chapter, we will characterize the structural and biochemical basis of the actin-myosin interaction and explain its relationship with myosin's cellular roles, with emphasis on the structural variation among myosin isoforms that enables their functional specialization. We will also discuss the impact of accessory proteins, such as the troponin-tropomyosin complex and myosin-binding protein C, on the formation and regulation of actomyosin cross-bridges.
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Affiliation(s)
- Ian Pepper
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, VA, USA
| | - Vitold E Galkin
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, VA, USA.
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11
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MacTaggart B, Kashina A. Posttranslational modifications of the cytoskeleton. Cytoskeleton (Hoboken) 2021; 78:142-173. [PMID: 34152688 DOI: 10.1002/cm.21679] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 06/13/2021] [Accepted: 06/16/2021] [Indexed: 12/12/2022]
Abstract
The cytoskeleton plays important roles in many essential processes at the cellular and organismal levels, including cell migration and motility, cell division, and the establishment and maintenance of cell and tissue architecture. In order to facilitate these varied functions, the main cytoskeletal components-microtubules, actin filaments, and intermediate filaments-must form highly diverse intracellular arrays in different subcellular areas and cell types. The question of how this diversity is conferred has been the focus of research for decades. One key mechanism is the addition of posttranslational modifications (PTMs) to the major cytoskeletal proteins. This posttranslational addition of various chemical groups dramatically increases the complexity of the cytoskeletal proteome and helps facilitate major global and local cytoskeletal functions. Cytoskeletal proteins undergo many PTMs, most of which are not well understood. Recent technological advances in proteomics and cell biology have allowed for the in-depth study of individual PTMs and their functions in the cytoskeleton. Here, we provide an overview of the major PTMs that occur on the main structural components of the three cytoskeletal systems-tubulin, actin, and intermediate filament proteins-and highlight the cellular function of these modifications.
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Affiliation(s)
- Brittany MacTaggart
- School of Veterinary Medicine, Department of Biomedical Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Anna Kashina
- School of Veterinary Medicine, Department of Biomedical Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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12
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N H, P SR, Sura M, Daddam JR. Structure prediction, molecular simulations of RmlD from Mycobacterium tuberculosis, and interaction studies of Rhodanine derivatives for anti-tuberculosis activity. J Mol Model 2021; 27:75. [PMID: 33547544 DOI: 10.1007/s00894-021-04696-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 01/26/2021] [Indexed: 12/14/2022]
Abstract
Tuberculosis is the most dangerous disease causing maximum deaths than any other, caused by single infectious agent. Due to multidrug resistant of Mycobacterium tuberculosis strains, there is a need of new drugs and drug targets. In this work, we have selected RmlD (α-dTDP-6-deoxy-lyxo-4-hexulose reductase) in the dTDP Rhamnose pathway as drug target to control tuberculosis using Rhodanine analogues. In order to study interaction of RmlD with Rhodanine analogues, a three-dimensional model based on crystal structures such as 1VLO from Clostridium, 1KBZ from Salmonella typhimurium, and 2GGS from Sulfolobus was generated using Modeller 9v7. The modeled structure reliability has been checked using programs such as Procheck, What if, Prosa, Verify 3D, and Errat. In an attempt to find new inhibitors for RmlD enzyme, docking studies were done with a series of Rhodanine and its analogues. Detailed analysis of enzyme-inhibitor interactions identified specific key residues, SER5, VAL9, ILE51, HIS54, and GLY55 which were important in forming hydrogen bonds in binding affinity. Homology modeling and docking studies on RmlD model provided valuable insight information for designing better inhibitors as novel anti-tuberculosis drugs by rational method.
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Affiliation(s)
- Harathi N
- Department of Biochemistry, G. Pulla Reddy Dental College, Kurnool, India
| | - Sreenivasa Reddy P
- Department of Oral and Maxillofacial Surgery, G. Pulla Reddy Dental College & Hospital, Kurnool, 518002, India
| | - Mounica Sura
- Department of Foodtechnology, Jawaharlalnehru Technological University Anantapur, Anantapur, 515001, India
| | - Jayasimha Rayalu Daddam
- Cardiovascular and Mitochondria Related Diseases Research Center, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan.
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13
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Mugnai ML, Thirumalai D. Step-Wise Hydration of Magnesium by Four Water Molecules Precedes Phosphate Release in a Myosin Motor. J Phys Chem B 2021; 125:1107-1117. [PMID: 33481593 DOI: 10.1021/acs.jpcb.0c10004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Molecular motors, such as myosin, kinesin, and dynein, convert the energy released by the hydrolysis of ATP into mechanical work, thus allowing them to undergo directional motion on cytoskeletal tracks. A pivotal step in the chemomechanical transduction in myosin motors occurs after they bind to the actin filament, which triggers the release of phosphate (Pi, product of ATP hydrolysis) and the rotation of the lever arm. Here, we investigate the mechanism of phosphate release in myosin VI using extensive molecular dynamics simulations involving multiple trajectories of several μs. Because the escape of phosphate is expected to occur on time-scales on the order of milliseconds or more in myosin VI, we observed Pi release only if the trajectories were initiated with a rotated phosphate inside the nucleotide binding pocket. We discovered that although Pi populates the traditional "back door" route, phosphate exits through various other gateways, thus establishing the heterogeneity in the escape routes. Remarkably, we observed that the release of phosphate is preceded by a stepwise hydration of the ADP-bound magnesium ion. The release of the anion occurred only after four water molecules hydrated the cation (Mg2+). By performing comparative structural analyses, we show that hydration of magnesium is the key step in the phosphate release in a number of ATPases and GTPases. Nature may have evolved hydration of Mg2+ as a general molecular switch for Pi release, which is a universal step in the catalytic cycle of many machines that share little sequence or structural similarity.
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Affiliation(s)
- Mauro Lorenzo Mugnai
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - D Thirumalai
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
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14
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Peng C, Wang J, Shi Y, Xu Z, Zhu W. Increasing the Sampling Efficiency of Protein Conformational Change by Combining a Modified Replica Exchange Molecular Dynamics and Normal Mode Analysis. J Chem Theory Comput 2020; 17:13-28. [PMID: 33351613 DOI: 10.1021/acs.jctc.0c00592] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Understanding conformational change at an atomic level is significant when determining a protein functional mechanism. Replica exchange molecular dynamics (REMD) is a widely used enhanced sampling method to explore protein conformational space. However, REMD with an explicit solvent model requires huge computational resources, immensely limiting its application. In this study, a variation of parallel tempering metadynamics (PTMetaD) with the omission of solvent-solvent interactions in exchange attempts and the use of low-frequency modes calculated by normal-mode analysis (NMA) as collective variables (CVs), namely ossPTMetaD, is proposed with the aim to accelerate MD simulations simultaneously in temperature and geometrical spaces. For testing the performance of ossPTMetaD, five protein systems with diverse biological functions and motion patterns were selected, including large-scale domain motion (AdK), flap movement (HIV-1 protease and BACE1), and DFG-motif flip in kinases (p38α and c-Abl). The simulation results showed that ossPTMetaD requires much fewer numbers of replicas than temperature REMD (T-REMD) with a reduction of ∼70% to achieve a similar exchange ratio. Although it does not obey the detailed balance condition, ossPTMetaD provides consistent results with T-REMD and experimental data. The high accessibility of the large conformational change of protein systems by ossPTMetaD, especially in simulating the very challenging DFG-motif flip of protein kinases, demonstrated its high efficiency and robustness in the characterization of the large-scale protein conformational change pathway and associated free energy profile.
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Affiliation(s)
- Cheng Peng
- CAS Key Laboratory of Receptor Research; Drug Discovery and Design Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai, 201203, China.,University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing, 100049, China
| | - Jinan Wang
- CAS Key Laboratory of Receptor Research; Drug Discovery and Design Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai, 201203, China
| | - Yulong Shi
- CAS Key Laboratory of Receptor Research; Drug Discovery and Design Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai, 201203, China.,University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing, 100049, China
| | - Zhijian Xu
- CAS Key Laboratory of Receptor Research; Drug Discovery and Design Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai, 201203, China.,University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing, 100049, China
| | - Weiliang Zhu
- CAS Key Laboratory of Receptor Research; Drug Discovery and Design Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai, 201203, China.,Open Studio for Druggability Research of Marine Lead Compounds, Qingdao National Laboratory for Marine Science and Technology, 1 Wenhai Road, Aoshanwei, Jimo, Qingdao 266237, China.,University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing, 100049, China
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15
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Papathoti NK, Saengchan C, Daddam JR, Thongprom N, Tonpho K, Thanh TL, Buensanteai N. Plant systemic acquired resistance compound salicylic acid as a potent inhibitor against SCF (SKP1-CUL1-F-box protein) mediated complex in Fusarium oxysporum by homology modeling and molecular dynamics simulations. J Biomol Struct Dyn 2020; 40:1472-1479. [PMID: 33047664 DOI: 10.1080/07391102.2020.1828168] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Fusarium oxysporum causes significant economic losses in many crop plants by causing root rot, necrosis, and wilting symptoms. Homology and molecular dynamics studies are promising tools for the detection in F. oxysporum of the systemic resistance compound, salicylic acid, for control of the SKP1-CUL1-F-box protein complex. The structure of SKP1-CUL1-F-box subunit Skp1 from F. oxysporum is produced by Modeler 9v7 for the conduct of docking studies. The Skp1 structure is based on the yeast Cdc4/Skp1 (PDB ID: 3MKS A) crystal structure collected by the Protein data bank. Applying molecular dynamic model simulation methods to the final predicted structure and further evaluated by 3D and PROCHECK test programmers, the final model is verified to be accurate. Applying GOLD 3.0.1, SCF Complex Skp1 is used to prevent stress-tolerant operation. The SKP1-CUL1-F-box model is predicted to be stabilized and tested as a stable docking structure. The predicted model of the SCF structure has been stabilized and confirmed to be a reliable structure for docking studies. The results indicated that GLN8, LYS9, VAL10, TRP11, GLU48, ASN49 in SCF complex are important determinant residues in binding as they have strong hydrogen bonding with salicylic acid, which showed best docking results with SKP1-CUL1-F-box complex subunit Skp1 with docking score 25.25KJ/mol. Insilco studies have been used to determine the mode of action of salicylic acid for Fusarium control. Salicylic acid hinders the SKP1-CUL1-F-box complex, which is important in protein-like interactions through hydrogen bodings. Results from docking studies have shown that the best energy for SKP1-CUL1-F-box was salicylic acid.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Narendra Kumar Papathoti
- School of Crop Production Technology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Chanon Saengchan
- School of Crop Production Technology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Jayasimha Rayulu Daddam
- Department of Cardiovascular and Mitochondrial Related Disease Research Center, Hualien Tzu Chi Hospital, Hualien, Taiwan
| | - Nattaya Thongprom
- School of Crop Production Technology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Kodchaphon Tonpho
- School of Crop Production Technology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Toan Le Thanh
- Crop Protection Department, College of Agriculture, Can Tho University, Can Tho city, Vietnam
| | - Natthiya Buensanteai
- School of Crop Production Technology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, Thailand
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16
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Schroer CFE, Baldauf L, van Buren L, Wassenaar TA, Melo MN, Koenderink GH, Marrink SJ. Charge-dependent interactions of monomeric and filamentous actin with lipid bilayers. Proc Natl Acad Sci U S A 2020; 117:5861-5872. [PMID: 32123101 PMCID: PMC7084070 DOI: 10.1073/pnas.1914884117] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The cytoskeletal protein actin polymerizes into filaments that are essential for the mechanical stability of mammalian cells. In vitro experiments showed that direct interactions between actin filaments and lipid bilayers are possible and that the net charge of the bilayer as well as the presence of divalent ions in the buffer play an important role. In vivo, colocalization of actin filaments and divalent ions are suppressed, and cells rely on linker proteins to connect the plasma membrane to the actin network. Little is known, however, about why this is the case and what microscopic interactions are important. A deeper understanding is highly beneficial, first, to obtain understanding in the biological design of cells and, second, as a possible basis for the building of artificial cortices for the stabilization of synthetic cells. Here, we report the results of coarse-grained molecular dynamics simulations of monomeric and filamentous actin in the vicinity of differently charged lipid bilayers. We observe that charges on the lipid head groups strongly determine the ability of actin to adsorb to the bilayer. The inclusion of divalent ions leads to a reversal of the binding affinity. Our in silico results are validated experimentally by reconstitution assays with actin on lipid bilayer membranes and provide a molecular-level understanding of the actin-membrane interaction.
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Affiliation(s)
- Carsten F E Schroer
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG, Groningen, The Netherlands
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - Lucia Baldauf
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands
- Living Matter Department, AMOLF, 1098 XG Amsterdam, The Netherlands
| | - Lennard van Buren
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands
- Living Matter Department, AMOLF, 1098 XG Amsterdam, The Netherlands
| | - Tsjerk A Wassenaar
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG, Groningen, The Netherlands
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - Manuel N Melo
- Instituto de Tecnologia Química e Biológica, New University of Lisbon, 2780-157, Oeiras, Portugal
| | - Gijsje H Koenderink
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands;
- Living Matter Department, AMOLF, 1098 XG Amsterdam, The Netherlands
| | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG, Groningen, The Netherlands;
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG, Groningen, The Netherlands
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17
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Pospich S, Merino F, Raunser S. Structural Effects and Functional Implications of Phalloidin and Jasplakinolide Binding to Actin Filaments. Structure 2020; 28:437-449.e5. [PMID: 32084355 DOI: 10.1016/j.str.2020.01.014] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Revised: 01/07/2020] [Accepted: 01/28/2020] [Indexed: 12/15/2022]
Abstract
Actin undergoes structural transitions during polymerization, ATP hydrolysis, and subsequent release of inorganic phosphate. Several actin-binding proteins sense specific states during this transition and can thus target different regions of the actin filament. Here, we show in atomic detail that phalloidin, a mushroom toxin that is routinely used to stabilize and label actin filaments, suspends the structural changes in actin, likely influencing its interaction with actin-binding proteins. Furthermore, high-resolution cryoelectron microscopy structures reveal structural rearrangements in F-actin upon inorganic phosphate release in phalloidin-stabilized filaments. We find that the effect of the sponge toxin jasplakinolide differs from the one of phalloidin, despite their overlapping binding site and similar interactions with the actin filament. Analysis of structural conformations of F-actin suggests that stabilizing agents trap states within the natural conformational space of actin.
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Affiliation(s)
- Sabrina Pospich
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund 44227, Germany
| | - Felipe Merino
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund 44227, Germany
| | - Stefan Raunser
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund 44227, Germany.
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18
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Daddam JR, Sreenivasulu B, Peddanna K, Umamahesh K. Designing, docking and molecular dynamics simulation studies of novel cloperastine analogues as anti-allergic agents: homology modeling and active site prediction for the human histamine H1 receptor. RSC Adv 2020; 10:4745-4754. [PMID: 35495246 PMCID: PMC9049021 DOI: 10.1039/c9ra09245e] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 01/09/2020] [Indexed: 11/21/2022] Open
Abstract
The present study predicts a three-dimensional model for the histamine H1 receptor and the design of antihistamine inhibitors using cloperastine as the core molecule by docking studies. In this work, we predicted a three-dimensional structure of the histamine H1 receptor using the MODELLER9V7 software. The protein structure was developed based on the crystal structure of the histamine H1 receptor, the lysozyme chimera of Escherichia virus T4 (PDB ID: 3RZE_A) target collected from the PDB data bank. Using molecular dynamics simulation methods, the final predicted structure is obtained and further analyzed by VERIFY3D and PROCHECK programs, confirming that the final model is reliable. The drug derivatives of cloperastine were designed and docking was performed with the designed ligands along with the drug. The predicted model of the histamine H1 receptor structure is stable and confirms that it is a reliable structure for docking studies. The results indicate that MET 183, THR 184 and ILE 187 in the histamine H1 receptor are important determinant residues for binding as they have strong hydrogen bonding with cloperastine derivatives. The drug derivatives were docked to the histamine H1 receptor protein by hydrogen bonding interactions and these interactions played an important role in the binding studies. The molecule 1-{2-[(4-chlorophenyl) (phenyl) methoxy] ethyl}-4-methylenepiperidine showed the best docking results with the histamine H1 receptor. The docking results predicted the best compounds, which may act as better drugs than cloperastine and in the future, these may be developed for anti-allergy therapy. The present study predicts a three-dimensional model for the histamine H1 receptor and the design of antihistamine inhibitors using cloperastine as the core molecule by docking studies.![]()
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Affiliation(s)
| | - Basha Sreenivasulu
- Department of Microbiology
- Sri Venkateswara University
- Tirupati
- India-517502
- Department of Biological Sciences
| | - Kotha Peddanna
- Department of Biochemistry
- Sri Venkateswara University
- Tirupati
- India-517502
- School of Chinese Medicine
| | - Katike Umamahesh
- Department of Biochemistry
- Sri Venkateswara University
- Tirupati
- India-517502
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19
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Kulke M, Uhrhan M, Geist N, Brüggemann D, Ohler B, Langel W, Köppen S. Phosphorylation of Fibronectin Influences the Structural Stability of the Predicted Interchain Domain. J Chem Inf Model 2019; 59:4383-4392. [PMID: 31509400 DOI: 10.1021/acs.jcim.9b00555] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
As a key player in cell adhesion, the glycoprotein fibronectin is involved in the complex mechanobiology of the extracellular matrix. Although the function of many modules in the fibronectin molecule has already been understood, the structure and biological relevance of the C-terminal cross-linked region (CTXL) still remains unclear. It is known that fibronectin is only phosphorylated in the CTXL domain, but no results have been presented to date, which indicate a biological function based on this phosphorylation. For the first time, we introduce a structural model of the CTXL region in fibronectin, which we obtained by exhaustive replica exchange molecular dynamics simulations (TIGER2hs). The sampling revealed a conformational landscape of the dimerization module, and the global minimum state showed an umbrella-like module body and conspicuous structural region with two feet. We observed that the CTXL foot region exhibits a structural stability in its physiological state, which disappears upon changes in the phosphorylation state. Thus, our in silico studies enabled us to show that the flexibility of the CTXL region is guided by phosphorylation. These results indicate an in vivo function of the CTXL domain in protein binding and cell adhesion, which is controlled by phosphorylation.
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Affiliation(s)
- Martin Kulke
- Biophysical Chemistry , University of Greifswald , Greifswald 17487 , Germany
| | | | - Norman Geist
- Biophysical Chemistry , University of Greifswald , Greifswald 17487 , Germany
| | | | - Bastian Ohler
- Biophysical Chemistry , University of Greifswald , Greifswald 17487 , Germany
| | - Walter Langel
- Biophysical Chemistry , University of Greifswald , Greifswald 17487 , Germany
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20
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Gong B, Wei X, Qian J, Lin Y. Modeling and Simulations of the Dynamic Behaviors of Actin-Based Cytoskeletal Networks. ACS Biomater Sci Eng 2019; 5:3720-3734. [DOI: 10.1021/acsbiomaterials.8b01228] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Bo Gong
- Department of Engineering Mechanics, Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Xi Wei
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
| | - Jin Qian
- Department of Engineering Mechanics, Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Yuan Lin
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
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21
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Fujiwara I, Takeda S, Oda T, Honda H, Narita A, Maéda Y. Polymerization and depolymerization of actin with nucleotide states at filament ends. Biophys Rev 2018; 10:1513-1519. [PMID: 30460458 PMCID: PMC6297080 DOI: 10.1007/s12551-018-0483-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 11/09/2018] [Indexed: 01/20/2023] Open
Abstract
Polymerization induces hydrolysis of ATP bound to actin, followed by γ-phosphate release, which helps advance the disassembly of actin filaments into ADP-G-actin. Mechanical understanding of this correlation between actin assembly and ATP hydrolysis has been an object of intensive studies in biochemistry and structural biology for many decades. Although actin polymerization and depolymerization occur only at either the barbed or pointed ends and the kinetic and equilibrium properties are substantially different from each other, characterizing their properties is difficult to do by bulk assays, as these assays report the average of all actin filaments in solution and are therefore not able to discern the properties of individual actin filaments. Biochemical studies of actin polymerization and hydrolysis were hampered by these inherent properties of actin filaments. Total internal reflection fluorescence (TIRF) microscopy overcame this problem by observing single actin filaments. With TIRF, we now know not only that each end has distinct properties, but also that the rate of γ-phosphate release is much faster from the terminals than from the interior of actin filaments. The rate of γ-phosphate release from actin filament ends is even more accelerated when latrunculin A is bound. These findings highlight the importance of resolving structural differences between actin molecules in the interior of the filament and those at either filament end. This review provides a history of observing actin filaments under light microscopy, an overview of dynamic properties of ATP hydrolysis at the end of actin filament, and structural views of γ-phosphate release.
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Affiliation(s)
- Ikuko Fujiwara
- Frontier Research Institute for Materials Science, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya, 466-8555, Japan.
| | - Shuichi Takeda
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan.
| | - Toshiro Oda
- Faculty of Health and Welfare, Tokai Gakuin University, Nakakirino-cyo 5-68, Kakamigahara, Gifu, 504-8511, Japan
| | - Hajime Honda
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan
| | - Akihiro Narita
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan
| | - Yuichiro Maéda
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan
- Toyota Physical and Chemical Research Institute, 41-1, Yokomichi, Nagakute, Aichi, 480-1192, Japan
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22
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Do PC, Lee EH, Le L. Steered Molecular Dynamics Simulation in Rational Drug Design. J Chem Inf Model 2018; 58:1473-1482. [DOI: 10.1021/acs.jcim.8b00261] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Phuc-Chau Do
- School of Biotechnology, International University, Vietnam National University, Ho Chi Minh City 700000, Vietnam
| | - Eric H. Lee
- Department of Medicine and Division of Hematology and Oncology, Loma Linda University Medical Center, Loma Linda, California 92350, United States
| | - Ly Le
- School of Biotechnology, International University, Vietnam National University, Ho Chi Minh City 700000, Vietnam
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23
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Structural transitions of F-actin upon ATP hydrolysis at near-atomic resolution revealed by cryo-EM. Nat Struct Mol Biol 2018; 25:528-537. [PMID: 29867215 DOI: 10.1038/s41594-018-0074-0] [Citation(s) in RCA: 120] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 05/02/2018] [Indexed: 11/08/2022]
Abstract
The function of actin is coupled to the nucleotide bound to its active site. ATP hydrolysis is activated during polymerization; a delay between hydrolysis and inorganic phosphate (Pi) release results in a gradient of ATP, ADP-Pi and ADP along actin filaments (F-actin). Actin-binding proteins can recognize F-actin's nucleotide state, using it as a local 'age' tag. The underlying mechanism is complex and poorly understood. Here we report six high-resolution cryo-EM structures of F-actin from rabbit skeletal muscle in different nucleotide states. The structures reveal that actin polymerization repositions the proposed catalytic base, His161, closer to the γ-phosphate. Nucleotide hydrolysis and Pi release modulate the conformational ensemble at the periphery of the filament, thus resulting in open and closed states, which can be sensed by coronin-1B. The drug-like toxin jasplakinolide locks F-actin in an open state. Our results demonstrate in detail how ATP hydrolysis links to F-actin's conformational dynamics and protein interaction.
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24
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Mehrafrooz B, Shamloo A. Mechanical differences between ATP and ADP actin states: A molecular dynamics study. J Theor Biol 2018; 448:94-103. [PMID: 29634959 DOI: 10.1016/j.jtbi.2018.04.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 03/31/2018] [Accepted: 04/06/2018] [Indexed: 11/15/2022]
Abstract
This paper aims to give a comprehensive atomistic modeling of the nanomechanical behavior of actin monomer. Actin is a ubiquitous and essential component of cytoskeleton which forms many different cellular structures. Despite for several years great effort has been devoted to the investigation of mechanical properties of the actin filament, studies on the nanomechanical behavior of actin monomer are still lacking. These scales are, however, important for a complete understanding of the role of actin as an important component in the cytoskeleton structure. Based on the accuracy of atomistic modeling methods such as molecular dynamics simulations, steered molecular dynamics method is performed to assess tension of monomeric G-actin molecule under different types of mechanical loading including axial and lateral. As a result, stress-strain curves are obtained in aqueous solution, with either ATP or ADP bound in the nucleotide binding pocket. The obtained results yield evaluation of the tensile stiffness of a single actin monomer in lateral and normal direction. In order to compare the behavior of ATP and ADP G-actins, the number of hydrogen bonds and nonbonded interactions between the nucleotide and the protein are analyzed. Moreover, The effect of virtual spring of steered molecular dynamics on the mechanical behavior of actin monomer is investigated. The results reveal increasing the virtual spring constant leads to convergence of the stiffness. Moreover, in this paper, a generalized model is proposed to extend the obtained results for the monomeric G-actin scale to the actin filament. Our modeling estimated a persistence length of actin filament 15.41 µm, close to experimental measurements. Moreover, In this paper, the breaking force actin-actin bond is evaluated using steered molecular dynamics simulation. By applying a tensile force, actin-actin bond ruptured at 4197.5 pN.
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Affiliation(s)
- Behzad Mehrafrooz
- Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran
| | - Amir Shamloo
- Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran.
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25
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Molecular dynamics and protein interaction studies of lipopeptide (Iturin A) on α- amylase of Spodoptera litura. J Theor Biol 2016; 415:41-47. [PMID: 27940096 DOI: 10.1016/j.jtbi.2016.12.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Revised: 11/24/2016] [Accepted: 12/07/2016] [Indexed: 11/23/2022]
Abstract
The small mottled willow moth (Spodoptera litura) is one of the best-known agricultural pest insects. To understand the insecticidal activity, we have selected iturin A compound produced by Bacillus amyloliquefaciens RHNK22 which showed the strongest and most common inhibitory effect on the Spodoptera litura protein. In this work we have identified the action of iturin A on α- amylase is a major digestive enzyme of Spodoptera litura using docking studies. A 3D model of α- amylase from Spodoptera litura was generated using 2HPH as a template with the help of Modeller7v7. With the aid of the molecular mechanics and molecular dynamics methods, the final model is obtained and is further checked by Procheck and Verify 3D graph programs, which showed that the final refined model is reliable. With this model, a adjustable docking study was performed with iturin A using GOLD software. The results indicated that ARG 18, THR15, LEU42 in α- amylase are important determinant residues in binding as they have strong hydrogen bonding interactions with iturin A. These hydrogen binding interactions play an important role for the stability of the complex.
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26
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Samyn DR, Van der Veken J, Van Zeebroeck G, Persson BL, Karlsson BCG. Key Residues and Phosphate Release Routes in the Saccharomyces cerevisiae Pho84 Transceptor: THE ROLE OF TYR179 IN FUNCTIONAL REGULATION. J Biol Chem 2016; 291:26388-26398. [PMID: 27875295 PMCID: PMC5159500 DOI: 10.1074/jbc.m116.738112] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 10/28/2016] [Indexed: 12/13/2022] Open
Abstract
Pho84, a major facilitator superfamily (MFS) protein, is the main high-affinity Pi transceptor in Saccharomyces cerevisiae Although transport mechanisms have been suggested for other MFS members, the key residues and molecular events driving transport by Pi:H+ symporters are unclear. The current Pho84 transport model is based on the inward-facing occluded crystal structure of the Pho84 homologue PiPT in the fungus Piriformospora indica However, this model is limited by the lack of experimental data on the regulatory residues for each stage of the transport cycle. In this study, an open, inward-facing conformation of Pho84 was used to study the release of Pi A comparison of this conformation with the model for Pi release in PiPT revealed that Tyr179 in Pho84 (Tyr150 in PiPT) is not part of the Pi binding site. This difference may be due to a lack of detailed information on the Pi release step in PiPT. Molecular dynamics simulations of Pho84 in which a residue adjacent to Tyr179, Asp178, is protonated revealed a conformational change in Pho84 from an open, inward-facing state to an occluded state. Tyr179 then became part of the binding site as was observed in the PiPT crystal structure. The importance of Tyr179 in regulating Pi release was supported by site-directed mutagenesis and transport assays. Using trehalase activity measurements, we demonstrated that the release of Pi is a critical step for transceptor signaling. Our results add to previous studies on PiPT, creating a more complete picture of the proton-coupled Pi transport cycle of a transceptor.
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Affiliation(s)
- Dieter R Samyn
- the Linnæus University Centre for Biomaterials Chemistry, Linnæus University, SE-391 82 Kalmar, Sweden
| | - Jeroen Van der Veken
- the Linnæus University Centre for Biomaterials Chemistry, Linnæus University, SE-391 82 Kalmar, Sweden
| | - Griet Van Zeebroeck
- the Department of Molecular Microbiology, VIB, Kasteelpark Arenberg 31, BE-3001 Leuven-Heverlee, Flanders, Belgium, and.,the Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Katholieke Universiteit Leuven, Kasteelpark Arenberg 31, BE-3001 Leuven-Heverlee, Flanders, Belgium
| | - Bengt L Persson
- the Linnæus University Centre for Biomaterials Chemistry, Linnæus University, SE-391 82 Kalmar, Sweden
| | - Björn C G Karlsson
- the Linnæus University Centre for Biomaterials Chemistry, Linnæus University, SE-391 82 Kalmar, Sweden, .,From the Computational Chemistry & Biochemistry Group
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27
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Kayode O, Wang R, Pendlebury DF, Cohen I, Henin RD, Hockla A, Soares AS, Papo N, Caulfield TR, Radisky ES. An Acrobatic Substrate Metamorphosis Reveals a Requirement for Substrate Conformational Dynamics in Trypsin Proteolysis. J Biol Chem 2016; 291:26304-26319. [PMID: 27810896 DOI: 10.1074/jbc.m116.758417] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 11/01/2016] [Indexed: 01/13/2023] Open
Abstract
The molecular basis of enzyme catalytic power and specificity derives from dynamic interactions between enzyme and substrate during catalysis. Although considerable effort has been devoted to understanding how conformational dynamics within enzymes affect catalysis, the role of conformational dynamics within protein substrates has not been addressed. Here, we examine the importance of substrate dynamics in the cleavage of Kunitz-bovine pancreatic trypsin inhibitor protease inhibitors by mesotrypsin, finding that the varied conformational dynamics of structurally similar substrates can profoundly impact the rate of catalysis. A 1.4-Å crystal structure of a mesotrypsin-product complex formed with a rapidly cleaved substrate reveals a dramatic conformational change in the substrate upon proteolysis. By using long all-atom molecular dynamics simulations of acyl-enzyme intermediates with proteolysis rates spanning 3 orders of magnitude, we identify global and local dynamic features of substrates on the nanosecond-microsecond time scale that correlate with enzymatic rates and explain differential susceptibility to proteolysis. By integrating multiple enhanced sampling methods for molecular dynamics, we model a viable conformational pathway between substrate-like and product-like states, linking substrate dynamics on the nanosecond-microsecond time scale with large collective substrate motions on the much slower time scale of catalysis. Our findings implicate substrate flexibility as a critical determinant of catalysis.
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Affiliation(s)
| | | | | | - Itay Cohen
- the Department of Biotechnology Engineering and the National Institute of Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel, and
| | | | | | - Alexei S Soares
- the Photon Sciences Directorate, Brookhaven National Laboratory, Upton, New York 11973
| | - Niv Papo
- the Department of Biotechnology Engineering and the National Institute of Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel, and
| | - Thomas R Caulfield
- Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida 32224,
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Lu H, Fagnant PM, Krementsova EB, Trybus KM. Severe Molecular Defects Exhibited by the R179H Mutation in Human Vascular Smooth Muscle α-Actin. J Biol Chem 2016; 291:21729-21739. [PMID: 27551047 DOI: 10.1074/jbc.m116.744011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 08/17/2016] [Indexed: 12/12/2022] Open
Abstract
Mutations in vascular smooth muscle α-actin (SM α-actin), encoded by ACTA2, are the most common cause of familial thoracic aortic aneurysms that lead to dissection (TAAD). The R179H mutation has a poor patient prognosis and is unique in causing multisystemic smooth muscle dysfunction (Milewicz, D. M., Østergaard, J. R., Ala-Kokko, L. M., Khan, N., Grange, D. K., Mendoza-Londono, R., Bradley, T. J., Olney, A. H., Ades, L., Maher, J. F., Guo, D., Buja, L. M., Kim, D., Hyland, J. C., and Regalado, E. S. (2010) Am. J. Med. Genet. A 152A, 2437-2443). Here, we characterize this mutation in expressed human SM α-actin. R179H actin shows severe polymerization defects, with a 40-fold higher critical concentration for assembly than WT SM α-actin, driven by a high disassembly rate. The mutant filaments are more readily severed by cofilin. Both defects are attenuated by copolymerization with WT. The R179H monomer binds more tightly to profilin, and formin binding suppresses nucleation and slows polymerization rates. Linear filaments will thus not be readily formed, and cells expressing R179H actin will likely have increased levels of monomeric G-actin. The cotranscription factor myocardin-related transcription factor-A, which affects cellular phenotype, binds R179H actin with less cooperativity than WT actin. Smooth muscle myosin moves R179H filaments more slowly than WT, even when copolymerized with equimolar amounts of WT. The marked decrease in the ability to form filaments may contribute to the poor patient prognosis and explain why R179H disrupts even visceral smooth muscle cell function where the SM α-actin isoform is present in low amounts. The R179H mutation has the potential to affect actin structure and function in both the contractile domain of the cell and the more dynamic cytoskeletal pool of actin, both of which are required for contraction.
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Affiliation(s)
- Hailong Lu
- From the Department of Molecular Physiology and Biophysics and University of Vermont, Burlington, Vermont 05446
| | - Patricia M Fagnant
- From the Department of Molecular Physiology and Biophysics and University of Vermont, Burlington, Vermont 05446
| | - Elena B Krementsova
- From the Department of Molecular Physiology and Biophysics and University of Vermont, Burlington, Vermont 05446
| | - Kathleen M Trybus
- From the Department of Molecular Physiology and Biophysics and University of Vermont, Burlington, Vermont 05446
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Meshach Paul D, Rajasekaran R. In silico approach to explore the disruption in the molecular mechanism of human hyaluronidase 1 by mutant E268K that directs Natowicz syndrome. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2016; 46:157-169. [PMID: 27424109 DOI: 10.1007/s00249-016-1151-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 06/02/2016] [Accepted: 07/01/2016] [Indexed: 01/27/2023]
Abstract
Natowicz syndrome (mucopolysaccharidoses type 9) is a lysosomal storage disorder caused by deficient or defective human hyaluronidase 1. The disorder is not well studied at the molecular level. Therefore, a new in silico approach was proposed to study the molecular basis on which one clinically observed mutation, Glu268Lys, results in a defective enzyme. The native and mutant structures were subjected to comparative analyses using a conformational sampling approach for geometrical variables viz, RMSF, RMSD, and Ramachandran plot. In addition, the strength of a Cys207-Cys221 disulfide bond and electrostatic interaction between Arg265 and Asp206 were studied, as they are known to be involved in the catalytic activity of the enzyme. Native and mutant E268K showed statistically significant variations with p < 0.05 in RMSD, Ramachandran plot, strengths of disulfide bond, and electrostatic interactions. Further, single model analysis showed variations between native and mutant structures in terms of intra-protein interactions, hydrogen bond dilution, secondary structure, and dihedral angles. Docking analysis predicted the mutant to have a less favorable substrate binding energy compared to the native protein. Additionally, steered MD analysis indicated that the substrate should have more affinity to the native than mutant enzymes. The observed changes theoretically explain the less favorable binding energy of substrate towards mutant E268K, thereby providing a structural basis for its reduced catalytic activity. Hence, our study provides a basis for understanding the disruption in the molecular mechanism of human hyaluronidase 1 by mutation E268K, which may prove useful for the development of synthetic chaperones as a treatment option for Natowicz syndrome.
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Affiliation(s)
- D Meshach Paul
- Computational Biology Lab, Department of Biotechnology, School of Bio Sciences and Technology, VIT University, Vellore, 632014, Tamil Nadu, India
| | - R Rajasekaran
- Computational Biology Lab, Department of Biotechnology, School of Bio Sciences and Technology, VIT University, Vellore, 632014, Tamil Nadu, India.
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Kudryashov DS, Reisler E. ATP and ADP actin states. Biopolymers 2016; 99:245-56. [PMID: 23348672 DOI: 10.1002/bip.22155] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 09/07/2012] [Indexed: 11/06/2022]
Abstract
This minireview is dedicated to the memory of Henryk Eisenberg and honors his major contributions to many areas of biophysics and to the analysis of macromolecular states and interactions in particular. This work reviews the ATP and ADP states of a ubiquitous protein, actins, and considers the present evidence for and against unique, nucleotide-dependent conformations of this protein. The effects of ATP and ADP on specific structural elements of actins, its loops and clefts, as revealed by mutational, crosslinking, spectroscopic, and EPR methods are discussed. It is concluded that the existing evidence points to dynamic equilibria of these structural elements among various conformational states in both ATP- and ADP-actins, with the nucleotides impacting the equilibria distributions.
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Affiliation(s)
- Dmitri S Kudryashov
- Department of Chemistry and Biochemistry, the Ohio State University, Columbus, OH 43210.
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Komuro Y, Re S, Kobayashi C, Muneyuki E, Sugita Y. CHARMM Force-Fields with Modified Polyphosphate Parameters Allow Stable Simulation of the ATP-Bound Structure of Ca(2+)-ATPase. J Chem Theory Comput 2015; 10:4133-42. [PMID: 26588553 DOI: 10.1021/ct5004143] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Adenosine triphosphate (ATP) is an indispensable energy source in cells. In a wide variety of biological phenomena like glycolysis, muscle contraction/relaxation, and active ion transport, chemical energy released from ATP hydrolysis is converted to mechanical forces to bring about large-scale conformational changes in proteins. Investigation of structure-function relationships in these proteins by molecular dynamics (MD) simulations requires modeling of ATP in solution and ATP bound to proteins with accurate force-field parameters. In this study, we derived new force-field parameters for the triphosphate moiety of ATP based on the high-precision quantum calculations of methyl triphosphate. We tested our new parameters on membrane-embedded sarcoplasmic reticulum Ca(2+)-ATPase and four soluble proteins. The ATP-bound structure of Ca(2+)-ATPase remains stable during MD simulations, contrary to the outcome in shorter simulations using original parameters. Similar results were obtained with the four ATP-bound soluble proteins. The new force-field parameters were also tested by investigating the range of conformations sampled during replica-exchange MD simulations of ATP in explicit water. Modified parameters allowed a much wider range of conformational sampling compared with the bias toward extended forms with original parameters. A diverse range of structures agrees with the broad distribution of ATP conformations in proteins deposited in the Protein Data Bank. These simulations suggest that the modified parameters will be useful in studies of ATP in solution and of the many ATP-utilizing proteins.
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Affiliation(s)
- Yasuaki Komuro
- Graduate School of Science and Engineering, Chuo University , 1-13-27, Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan.,RIKEN Theoretical Molecular Science Laboratory , 2-1, Hirosawa, Wako-shi, Saitama 351-0198, Japan.,RIKEN Advanced Institute for Computational Science, International Medical Device Alliance (IMDA) 6F , 1-6-5 minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Suyong Re
- RIKEN Theoretical Molecular Science Laboratory , 2-1, Hirosawa, Wako-shi, Saitama 351-0198, Japan
| | - Chigusa Kobayashi
- RIKEN Advanced Institute for Computational Science, International Medical Device Alliance (IMDA) 6F , 1-6-5 minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Eiro Muneyuki
- Graduate School of Science and Engineering, Chuo University , 1-13-27, Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan
| | - Yuji Sugita
- RIKEN Theoretical Molecular Science Laboratory , 2-1, Hirosawa, Wako-shi, Saitama 351-0198, Japan.,RIKEN Advanced Institute for Computational Science, International Medical Device Alliance (IMDA) 6F , 1-6-5 minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.,RIKEN Quantitative Biology Center, International Medical Device Alliance (IMDA) 6F , 1-6-5 minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.,RIKEN iTHES , 2-1, Hirosawa, Wako-shi, Saitama 351-0198, Japan
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Cortes-Ciriano I, Bouvier G, Nilges M, Maragliano L, Malliavin TE. Temperature Accelerated Molecular Dynamics with Soft-Ratcheting Criterion Orients Enhanced Sampling by Low-Resolution Information. J Chem Theory Comput 2015; 11:3446-54. [PMID: 26575778 DOI: 10.1021/acs.jctc.5b00153] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Many proteins exhibit an equilibrium between multiple conformations, some of them being characterized only by low-resolution information. Visiting all conformations is a demanding task for computational techniques performing enhanced but unfocused exploration of collective variable (CV) space. Otherwise, pulling a structure toward a target condition biases the exploration in a way difficult to assess. To address this problem, we introduce here the soft-ratcheting temperature-accelerated molecular dynamics (sr-TAMD), where the exploration of CV space by TAMD is coupled to a soft-ratcheting algorithm that filters the evolving CV values according to a predefined criterion. Any low resolution or even qualitative information can be used to orient the exploration. We validate this technique by exploring the conformational space of the inactive state of the catalytic domain of the adenyl cyclase AC from Bordetella pertussis. The domain AC gets activated by association with calmodulin (CaM), and the available crystal structure shows that in the complex the protein has an elongated shape. High-resolution data are not available for the inactive, CaM-free protein state, but hydrodynamic measurements have shown that the inactive AC displays a more globular conformation. Here, using as CVs several geometric centers, we use sr-TAMD to enhance CV space sampling while filtering for CV values that correspond to centers moving close to each other, and we thus rapidly visit regions of conformational space that correspond to globular structures. The set of conformations sampled using sr-TAMD provides the most extensive description of the inactive state of AC up to now, consistent with available experimental information.
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Affiliation(s)
- Isidro Cortes-Ciriano
- Unité de Bioinformatique Structurale, CNRS UMR 3528, Structural Biology and Chemistry Department, Institut Pasteur , 25-28, rue Dr. Roux, 75 724 Paris, France
| | - Guillaume Bouvier
- Unité de Bioinformatique Structurale, CNRS UMR 3528, Structural Biology and Chemistry Department, Institut Pasteur , 25-28, rue Dr. Roux, 75 724 Paris, France
| | - Michael Nilges
- Unité de Bioinformatique Structurale, CNRS UMR 3528, Structural Biology and Chemistry Department, Institut Pasteur , 25-28, rue Dr. Roux, 75 724 Paris, France
| | - Luca Maragliano
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia , Genoa, Italy
| | - Thérèse E Malliavin
- Unité de Bioinformatique Structurale, CNRS UMR 3528, Structural Biology and Chemistry Department, Institut Pasteur , 25-28, rue Dr. Roux, 75 724 Paris, France
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Wakai N, Takemura K, Morita T, Kitao A. Mechanism of deep-sea fish α-actin pressure tolerance investigated by molecular dynamics simulations. PLoS One 2014; 9:e85852. [PMID: 24465747 PMCID: PMC3896411 DOI: 10.1371/journal.pone.0085852] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2013] [Accepted: 12/03/2013] [Indexed: 12/01/2022] Open
Abstract
The pressure tolerance of monomeric α-actin proteins from the deep-sea fish Coryphaenoides armatus and C. yaquinae was compared to that of non-deep-sea fish C. acrolepis, carp, and rabbit/human/chicken actins using molecular dynamics simulations at 0.1 and 60 MPa. The amino acid sequences of actins are highly conserved across a variety of species. The actins from C. armatus and C. yaquinae have the specific substitutions Q137K/V54A and Q137K/L67P, respectively, relative to C. acrolepis, and are pressure tolerant to depths of at least 6000 m. At high pressure, we observed significant changes in the salt bridge patterns in deep-sea fish actins, and these changes are expected to stabilize ATP binding and subdomain arrangement. Salt bridges between ATP and K137, formed in deep-sea fish actins, are expected to stabilize ATP binding even at high pressure. At high pressure, deep-sea fish actins also formed a greater total number of salt bridges than non-deep-sea fish actins owing to the formation of inter-helix/strand and inter-subdomain salt bridges. Free energy analysis suggests that deep-sea fish actins are stabilized to a greater degree by the conformational energy decrease associated with pressure effect.
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Affiliation(s)
- Nobuhiko Wakai
- Department of Computational Biology, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan
| | - Kazuhiro Takemura
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Takami Morita
- Research Center for Fisheries Oceanography and Marine Ecosystem, National Research Institute of Fisheries Sciences, Fisheries Research Agency, Kanagawa, Japan
| | - Akio Kitao
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
- * E-mail:
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34
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Investigation of the binding network of IGF-I on the cavity surface of IGFBP4. J Mol Model 2013; 19:5257-66. [DOI: 10.1007/s00894-013-2020-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 09/22/2013] [Indexed: 10/26/2022]
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Kalyaanamoorthy S, Chen YPP. Modelling and enhanced molecular dynamics to steer structure-based drug discovery. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2013; 114:123-36. [PMID: 23827463 DOI: 10.1016/j.pbiomolbio.2013.06.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 05/31/2013] [Accepted: 06/22/2013] [Indexed: 10/26/2022]
Abstract
The ever-increasing gap between the availabilities of the genome sequences and the crystal structures of proteins remains one of the significant challenges to the modern drug discovery efforts. The knowledge of structure-dynamics-functionalities of proteins is important in order to understand several key aspects of structure-based drug discovery, such as drug-protein interactions, drug binding and unbinding mechanisms and protein-protein interactions. This review presents a brief overview on the different state of the art computational approaches that are applied for protein structure modelling and molecular dynamics simulations of biological systems. We give an essence of how different enhanced sampling molecular dynamics approaches, together with regular molecular dynamics methods, assist in steering the structure based drug discovery processes.
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Affiliation(s)
- Subha Kalyaanamoorthy
- Department of Computer Science and Computer Engineering, Faculty of Science, Technology and Engineering, La Trobe University, Melbourne, VIC 3086, Australia
| | - Yi-Ping Phoebe Chen
- Department of Computer Science and Computer Engineering, Faculty of Science, Technology and Engineering, La Trobe University, Melbourne, VIC 3086, Australia.
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36
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Freedman H, Laino T, Curioni A. Reaction Dynamics of ATP Hydrolysis in Actin Determined by ab Initio Molecular Dynamics Simulations. J Chem Theory Comput 2012; 8:3373-83. [PMID: 26605743 DOI: 10.1021/ct3003282] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Energy released by the hydrolysis of the high-energy phosphate bond of nucleoside triphosphate (NTP) cofactors is the driving force behind most biological processes. To understand how this energy is used to induce differences in protein structure and function, we examine the transfer of vibrational energy into the nucleotide-bound actin active site immediately after reaction activation. To this end, we perform Born-Oppenheimer molecular dynamics simulations of the active site at the level of density functional theory (DFT) starting at the calculated transition state (TS) structure. Similarly to the mechanism determined in many nucleotide-bound protein systems, the Os-Pγ bond is first elongated. Then, nucleophilic attack of the lytic water on Pγ occurs. Subsequently, protons are transferred in a cycle formed by water molecules, a protein residue, Asp154, and the γ-phosphate group, resulting in the formation of H2PO4(-). To investigate the possible creation of excited vibrational states in the products, power spectra of bond-length autocorrelation functions for relevant bonds within the active site are compared for simulations that start at the TS, at reactants, and at reaction end products. The hydroxyl bond formed in the final proton transfer to the phosphate molecule is observed to exhibit relatively high kinetic energies and large oscillations during reaction. It is also likely that some of the energy released by the reaction is captured by the low-energy stretching vibrations of the phosphoryl bonds of orthophosphate, which oscillate with large amplitudes in nonequilibrium simulations of end products.
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Affiliation(s)
- Holly Freedman
- CCMAR, FCT, University of Algarve, Campus de Gambelas, Faro, Portugal
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37
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Fuchigami S, Fujisaki H, Matsunaga Y, Kidera A. Protein Functional Motions: Basic Concepts and Computational Methodologies. ADVANCING THEORY FOR KINETICS AND DYNAMICS OF COMPLEX, MANY-DIMENSIONAL SYSTEMS: CLUSTERS AND PROTEINS 2011. [DOI: 10.1002/9781118087817.ch2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Yamaoka H, Matsushita S, Shimada Y, Adachi T. Multiscale modeling and mechanics of filamentous actin cytoskeleton. Biomech Model Mechanobiol 2011; 11:291-302. [PMID: 21614531 DOI: 10.1007/s10237-011-0317-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 05/08/2011] [Indexed: 01/07/2023]
Affiliation(s)
- Hidetaka Yamaoka
- Computational Cell Biomechanics Team, VCAD System Research Program, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
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Matsushita S, Inoue Y, Hojo M, Sokabe M, Adachi T. Effect of tensile force on the mechanical behavior of actin filaments. J Biomech 2011; 44:1776-81. [PMID: 21536289 DOI: 10.1016/j.jbiomech.2011.04.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 03/29/2011] [Accepted: 04/09/2011] [Indexed: 01/08/2023]
Abstract
Actin filaments are the most abundant components of the cellular cytoskeleton, and play critical roles in various cellular functions such as migration, division and shape control. In these activities, mechanical tension causes structural changes in the double-helical structure of the actin filament, which is a key modulator of cytoskeletal reorganization. This study performed large-scale molecular dynamics (MD) and steered MD simulations to quantitatively analyze the effects of tensile force on the mechanical behavior of actin filaments. The results revealed that when a tensile force of 200pN was applied to a filament consisting of 14 actin subunits, the twist angle of the filament decreased by approximately 20°, corresponding to a rotation of approximately -2° per subunit, representing a critical structural change in actin filaments. Based on these structural changes, the variance in filament length and twist angle was found to decrease, leading to increases in extensional and torsional stiffness. Torsional stiffness increased significantly under the tensile condition, and the ratio of filament stiffness under tensile force to that under no external force increased significantly on longer temporal scales. The results obtained from this study contribute to the understanding of mechano-chemical interactions concerning actin dynamics, showing that increased tensile force in the filament prevents actin regulatory proteins from binding to the filament.
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Affiliation(s)
- Shinji Matsushita
- Department of Biomechanics, Research Center for Nano Medical Engineering, Institute for Frontier Medical Sciences, Kyoto University, Sakyo, Kyoto 606-8507, Japan
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Matsushita S, Adachi T, Inoue Y, Hojo M, Sokabe M. Evaluation of extensional and torsional stiffness of single actin filaments by molecular dynamics analysis. J Biomech 2010; 43:3162-7. [DOI: 10.1016/j.jbiomech.2010.07.022] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Revised: 06/30/2010] [Accepted: 07/25/2010] [Indexed: 11/28/2022]
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Murakami K, Yasunaga T, Noguchi TQP, Gomibuchi Y, Ngo KX, Uyeda TQP, Wakabayashi T. Structural basis for actin assembly, activation of ATP hydrolysis, and delayed phosphate release. Cell 2010; 143:275-87. [PMID: 20946985 DOI: 10.1016/j.cell.2010.09.034] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Revised: 05/10/2010] [Accepted: 09/01/2010] [Indexed: 10/18/2022]
Abstract
Assembled actin filaments support cellular signaling, intracellular trafficking, and cytokinesis. ATP hydrolysis triggered by actin assembly provides the structural cues for filament turnover in vivo. Here, we present the cryo-electron microscopic (cryo-EM) structure of filamentous actin (F-actin) in the presence of phosphate, with the visualization of some α-helical backbones and large side chains. A complete atomic model based on the EM map identified intermolecular interactions mediated by bound magnesium and phosphate ions. Comparison of the F-actin model with G-actin monomer crystal structures reveals a critical role for bending of the conserved proline-rich loop in triggering phosphate release following ATP hydrolysis. Crystal structures of G-actin show that mutations in this loop trap the catalytic site in two intermediate states of the ATPase cycle. The combined structural information allows us to propose a detailed molecular mechanism for the biochemical events, including actin polymerization and ATPase activation, critical for actin filament dynamics.
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Affiliation(s)
- Kenji Murakami
- Department of Biosciences, School of Science and Engineering, Teikyo University, Toyosatodai 1-1, Utsunomiya 320-8551, Japan
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Kudryashov DS, Grintsevich EE, Rubenstein PA, Reisler E. A nucleotide state-sensing region on actin. J Biol Chem 2010; 285:25591-601. [PMID: 20530485 DOI: 10.1074/jbc.m110.123869] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The nucleotide state of actin (ATP, ADP-P(i), or ADP) is known to impact its interactions with other actin molecules upon polymerization as well as with multiple actin binding proteins both in the monomeric and filamentous states of actin. Recently, molecular dynamics simulations predicted that a sequence located at the interface of subdomains 1 and 3 (W-loop; residues 165-172) changes from an unstructured loop to a beta-turn conformation upon ATP hydrolysis (Zheng, X., Diraviyam, K., and Sept, D. (2007) Biophys. J. 93, 1277-1283). This region participates directly in the binding to other subunits in F-actin as well as to cofilin, profilin, and WH2 domain proteins and, therefore, could contribute to the nucleotide sensitivity of these interactions. The present study demonstrates a reciprocal communication between the W-loop region and the nucleotide binding cleft on actin. Point mutagenesis of residues 167, 169, and 170 and their site-specific labeling significantly affect the nucleotide release from the cleft region, whereas the ATP/ADP switch alters the fluorescence of probes located in the W-loop. In the ADP-P(i) state, the W-loop adopts a conformation similar to that in the ATP state but different from the ADP state. Binding of latrunculin A to the nucleotide cleft favors the ATP-like conformation of the W-loop, whereas ADP-ribosylation of Arg-177 forces the W-loop into a conformation distinct from those in the ADP and ATP-states. Overall, our experimental data suggest that the W-loop of actin is a nucleotide sensor, which may contribute to the nucleotide state-dependent changes in F-actin and nucleotide state-modulated interactions of both G- and F-actin with actin-binding proteins.
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Affiliation(s)
- Dmitri S Kudryashov
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA.
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Differential binding of bispyridinium oxime drugs with acetylcholinesterase. Acta Pharmacol Sin 2010; 31:313-28. [PMID: 20140002 DOI: 10.1038/aps.2009.193] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
AIM To performe a time-dependent topographical delineation of protein-drug interactions to gain molecular insight into the supremacy of Ortho-7 over HI-6 in reactivating tabun-conjugated mouse acetylcholinesterase (mAChE). METHODS We conducted all-atom steered molecular dynamics simulations of the two protein-drug complexes. Through a host of protein-drug interaction parameters (rupture force profiles, hydrogen bonds, water bridges, hydrophobic interactions), geometrical, and orientation ordering of the drugs, we monitored the enzyme's response during the release of the drugs from its active-site. RESULTS The results show the preferential binding of the drugs with the enzyme. The pyridinium ring of HI-6 shows excellent complementary binding with the peripheral anionic site, whereas one of two identical pyridinium rings of Ortho-7 has excellent binding compatibility in the enzyme active-site where it can orchestrate the reactivation process. We found that the active pyridinium ring of HI-6 undergoes a complete turn along the active site axis, directed away from the active-site region during the course of the simulation. CONCLUSION Due to excellent cooperative binding of Ortho-7, as rendered by several cation-pi interactions with the active-site gorge of the enzyme, Ortho-7 may be a more efficient reactivator than HI-6. Our work supports the growing body of evidence that the efficacy of the drugs is due to the differential bindings of the oximes with AChE and can aid to the rational design of oxime drugs.
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Wang Y, Zhang L, Cheng J. Steered molecular dynamics simulation of the detaching process of two parallel surfaces glued together by a single polyethylene chain. J Appl Polym Sci 2010. [DOI: 10.1002/app.29626] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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45
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Zhang B, Su ZC, Tay TE, Tan VBC. Mechanism of CDK5 activation revealed by steered molecular dynamics simulations and energy calculations. J Mol Model 2009; 16:1159-68. [DOI: 10.1007/s00894-009-0629-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2009] [Accepted: 11/15/2009] [Indexed: 02/04/2023]
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Hsin J, Gumbart J, Trabuco LG, Villa E, Qian P, Hunter CN, Schulten K. Protein-induced membrane curvature investigated through molecular dynamics flexible fitting. Biophys J 2009; 97:321-9. [PMID: 19580770 PMCID: PMC2711417 DOI: 10.1016/j.bpj.2009.04.031] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2009] [Revised: 04/04/2009] [Accepted: 04/07/2009] [Indexed: 10/20/2022] Open
Abstract
In the photosynthetic purple bacterium Rhodobacter (Rba.) sphaeroides, light is absorbed by membrane-bound light-harvesting (LH) proteins LH1 and LH2. LH1 directly surrounds the reaction center (RC) and, together with PufX, forms a dimeric (RC-LH1-PufX)2 protein complex. In LH2-deficient Rba. sphaeroides mutants, RC-LH1-PufX dimers aggregate into tubular vesicles with a radius of approximately 250-550 A, making RC-LH1-PufX one of the few integral membrane proteins known to actively induce membrane curvature. Recently, a three-dimensional electron microscopy density map showed that the Rba. sphaeroides RC-LH1-PufX dimer exhibits a prominent bend at its dimerizing interface. To investigate the curvature properties of this highly bent protein, we employed molecular dynamics simulations to fit an all-atom structural model of the RC-LH1-PufX dimer within the electron microscopy density map. The simulations reveal how the dimer produces a membrane with high local curvature, even though the location of PufX cannot yet be determined uniquely. The resulting membrane curvature agrees well with the size of RC-LH1-PufX tubular vesicles, and demonstrates how the local curvature properties of the RC-LH1-PufX dimer propagate to form the observed long-range organization of the Rba. sphaeroides tubular vesicles.
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Affiliation(s)
- Jen Hsin
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - James Gumbart
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Leonardo G. Trabuco
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Elizabeth Villa
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Pu Qian
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - C. Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - Klaus Schulten
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
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Pollard TD, Berro J. Mathematical models and simulations of cellular processes based on actin filaments. J Biol Chem 2008; 284:5433-7. [PMID: 18940808 DOI: 10.1074/jbc.r800043200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Actin filaments help to maintain the physical integrity of cells and participate in many processes that produce cellular movements. Studies of the processes that depend on actin filaments have progressed to the point where mathematical models and computer simulations are an essential part of the experimental toolkit. These quantitative models integrate knowledge about the structures of the key proteins and the rate and equilibrium constants for the reactions for comparison with a growing body of quantitative measurements of dynamic processes in live cells. Models and simulations are essential because it is impossible to appreciate by intuition alone the properties that emerge from a network of coupled reactions, particularly when the system contains many components, and force is one of the parameters.
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Affiliation(s)
- Thomas D Pollard
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06520-8103, USA.
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Shrivastava IH, Jiang J, Amara SG, Bahar I. Time-resolved mechanism of extracellular gate opening and substrate binding in a glutamate transporter. J Biol Chem 2008; 283:28680-90. [PMID: 18678877 PMCID: PMC2568915 DOI: 10.1074/jbc.m800889200] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Glutamate transporters, also referred to as excitatory amino acid
transporters (EAATs), are membrane proteins that regulate glutamatergic signal
transmission by clearing excess glutamate after its release at synapses. A
structure-based understanding of their molecular mechanisms of function has
been elusive until the recent determination of the x-ray structure of an
archaeal transporter, GltPh. GltPh exists as a trimer,
with each subunit containing a core region that mediates substrate
translocation. In the present study a series of molecular dynamics simulations
have been conducted and analyzed in light of new experimental data on
substrate binding properties of EAATs. The simulations provide for the first
time a full atomic description of the time-resolved events that drive the
recognition and binding of substrate. The core region of each subunit exhibits
an intrinsic tendency to open the helical hairpin HP2 loop, the extracellular
gate, within tens of nanoseconds exposing conserved polar residues that serve
as attractors for substrate binding. The NMDGT motif on the partially unwound
part of the transmembrane helix TM7 and the residues Asp-390 and Asp-394 on
TM8 are also distinguished by their important role in substrate binding and
close interaction with mediating water molecules and/or sodium ions. The
simulations reveal a Na+ binding site comprised in part of Leu-303
on TM7 and Asp-405 on TM8 and support a role for sodium ions in stabilizing
substrate-bound conformers. The functional importance of Leu-303 or its
counterpart Leu-391 in human EAAT1 (hEAAT1) is confirmed by site-directed
mutagenesis and Na+ dependence assays conducted with hEAAT1 mutants
L391C and L391A.
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Affiliation(s)
- Indira H Shrivastava
- Department of Computational Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA
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49
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Bathe M. A finite element framework for computation of protein normal modes and mechanical response. Proteins 2008; 70:1595-609. [PMID: 17975833 DOI: 10.1002/prot.21708] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A computational framework based on the Finite Element Method is presented to calculate the normal modes and mechanical response of proteins and their supramolecular assemblies. Motivated by elastic network models, proteins are treated as continuum elastic solids with molecular volume defined by their solvent-excluded surface. The discretized Finite Element representation is obtained using a surface simplification algorithm that facilitates the generation of models of arbitrary prescribed spatial resolution. The procedure is applied to a mutant of T4 phage lysozyme, G-actin, syntenin, cytochrome-c', beta-tubulin, and the supramolecular assembly filamentous actin (F-actin). Equilibrium thermal fluctuations of alpha-carbon atoms and their inter-residue correlations compare favorably with all-atom-based results, the Rotational-Translational Block procedure, and experiment. Additionally, the free vibration and compressive buckling responses of F-actin are in quantitative agreement with experiment. The proposed methodology is applicable to any protein or protein assembly and facilitates the incorporation of specific atomic-level interactions, including aqueous-electrolyte-mediated electrostatic effects and solvent damping. The procedure is equally applicable to proteins with known atomic coordinates as it is to electron density maps of proteins, protein complexes, and supramolecular assemblies of unknown atomic structure.
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Affiliation(s)
- Mark Bathe
- Arnold Sommerfeld Zentrum für Theoretische Physik and Center for NanoScience, Ludwig-Maximilians-Universität München, Theresienstrasse 37, 80333 Munich, Germany.
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Abstract
Molecular modeling techniques have truly come of age in recent decades, and here we cover several of the most commonly used techniques, namely molecular dynamics, Brownian dynamics, and molecular docking. In each case, we explain the physical basis and limitations of the various techniques and then illustrate their application to various problems related to the cytoskeleton. This set of studies covers a relatively wide range of examples and is comprehensive enough to clearly see how these techniques could be applied to other systems. Finally, we cover several related methodologies that expand on these basic techniques to allow for more detailed and specific simulation and analysis.
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Affiliation(s)
- Xiange Zheng
- Department of Biomedical Engineering and Center for Computational Biology, Washington University, St. Louis, Missouri 63130, USA
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