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Buehl CJ, Goff NJ, Mikhova M, Hardwick SW, Blundell TL, Modesti M, Schmidt JC, Chaplin A, Meek K. Unravelling the complexities of DNA-PK activation by structure-based mutagenesis. RESEARCH SQUARE 2023:rs.3.rs-3627471. [PMID: 38168382 PMCID: PMC10760257 DOI: 10.21203/rs.3.rs-3627471/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
It has been known for decades that the DNA-dependent protein kinase (DNA-PK) is only an active serine/threonine protein kinase when it is bound to a DNA double-stranded end; still, the molecular details of how this activation is achieved have remained elusive. The recent surge in structural information for DNA-PK complexes has provided valuable insights into the process of DNA end recognition by DNA-PK. A particularly intriguing feature of this kinase is a region of the protein that can transition from a seemingly structurally disordered state to a single alpha-helix that traverses down the DNA binding cradle. The DNA-PK bound DNA end of the DNA substrate engages with and appears to split around this helix which has been named the DNA End Blocking helix (DEB). Here a mutational approach is utilized to clarify the role of the DEB, and how DNA ends activate the enzyme. Our data suggest two distinct methods of kinase activation that is dependent on the DNA end chemistry. If the DNA end can split around the helix and stabilize the interaction between the DNA end and the DEB with a recently defined Helix-Hairpin-Helix (HHH) motif, the kinase forms an end-protection monomer that is active towards DNA-PK's many substrates. But if the DNA end cannot stably interact with the DEB [because of the DNA end structure, for instance hairpins, or because the DEB has been disrupted by mutation], the kinase is only partially activated, resulting in specific autophosphorylations of the DNA-PK monomer that allows nucleolytic end-processing. We posit that mutants that disrupt the capacity to stably generate the DEB/HHH DNA end-interaction are inefficient in generating the dimer complex that is requisite for NHEJ. In support of this idea, mutations that promote formation of this dimer partially rescue the severe cellular phenotypes associated with mutation of the DEB helix.
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Affiliation(s)
- Christopher J Buehl
- College of Veterinary Medicine, Department of Microbiology & Molecular Genetics, Department of Pathobiology & Diagnostic Investigation, Michigan State University, East Lansing, MI 48824, USA
| | - Noah J Goff
- College of Veterinary Medicine, Department of Microbiology & Molecular Genetics, Department of Pathobiology & Diagnostic Investigation, Michigan State University, East Lansing, MI 48824, USA
| | - Mariia Mikhova
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, U.S.A
- Institute for Quantitative Health Sciences and Engineering, Michigan State University, East Lansing, MI, U.S.A
| | - Steven W Hardwick
- CryoEM Facility, Department of Biochemistry, University of Cambridge, Sanger Building, Tennis Court Road, Cambridge CB2 1GA, United Kingdom
| | - Thomas L Blundell
- Department of Biochemistry, University of Cambridge, Sanger Building, Tennis Court Road, Cambridge, CB2 1GA, United Kingdom
| | - Mauro Modesti
- Cancer Research Center of Marseille, Department of Genome Integrity, CNRS UMR7258, Inserm U1068, Institut Paoli-Calmettes, Aix Marseille Univ, Marseille, France
| | - Jens C Schmidt
- Institute for Quantitative Health Sciences and Engineering, Michigan State University, East Lansing, MI, U.S.A
- Department of Obstetrics, Gynecology, and Reproductive Biology, Michigan State University, East Lansing MI, U.S.A
| | - Amanda Chaplin
- CryoEM Facility, Department of Biochemistry, University of Cambridge, Sanger Building, Tennis Court Road, Cambridge CB2 1GA, United Kingdom
- Leicester Institute for Structural and Chemical Biology, Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - Katheryn Meek
- College of Veterinary Medicine, Department of Microbiology & Molecular Genetics, Department of Pathobiology & Diagnostic Investigation, Michigan State University, East Lansing, MI 48824, USA
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Das SK, Kumar A, Hao F, Cutter DiPiazza AR, Fang H, Lee TH, Hayes JJ. Histone H3 Tail Modifications Alter Structure and Dynamics of the H1 C-Terminal Domain Within Nucleosomes. J Mol Biol 2023; 435:168242. [PMID: 37619707 PMCID: PMC10530611 DOI: 10.1016/j.jmb.2023.168242] [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: 06/27/2023] [Revised: 08/10/2023] [Accepted: 08/10/2023] [Indexed: 08/26/2023]
Abstract
The highly positively charged and intrinsically disordered H1 C-terminal domain (CTD) undergoes extensive condensation upon binding to nucleosomes, and stabilizes nucleosomes and higher-order chromatin structures but its interactions in chromatin are not well defined. Using single-molecule FRET we found that about half of the H1 CTDs in H1-nucleosome complexes exhibit well-defined FRET values indicative of distinct, static conformations, while the remainder of the population exhibits exchange between multiple defined FRET structures. Moreover, crosslinking studies indicate that the first 30 residues of the H1 CTD participate in relatively localized contacts with the first ∼25 bp of linker DNA, and that two separate regions in the CTD contribute to H1-dependent organization of linker DNA. Finally, we show that acetylation mimetics within the histone H3 tail markedly reduce the overall extent of H1 CTD condensation and significantly increase the fraction of H1 CTDs undergoing dynamic exchange between FRET states. Our results indicate the nucleosome-bound H1 CTD adopts loosely defined structures that exhibit significantly enhanced dynamics and decondensation upon epigenetic acetylation within the H3 tail.
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Affiliation(s)
- Subhra Kanti Das
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, United States
| | - Ashok Kumar
- Department of Biochemistry and Biophysics, Rochester University Medical Center, Rochester, NY 14625, United States
| | - Fanfan Hao
- Department of Biochemistry and Biophysics, Rochester University Medical Center, Rochester, NY 14625, United States
| | - Amber R Cutter DiPiazza
- Department of Biochemistry and Biophysics, Rochester University Medical Center, Rochester, NY 14625, United States
| | - He Fang
- Department of Biochemistry and Biophysics, Rochester University Medical Center, Rochester, NY 14625, United States
| | - Tae-Hee Lee
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, United States.
| | - Jeffrey J Hayes
- Department of Biochemistry and Biophysics, Rochester University Medical Center, Rochester, NY 14625, United States.
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3
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Das SK, Kumar A, Hao F, DiPiazza ARC, Lee TH, Hayes JJ. Histone H3 tail modifications regulate structure and dynamics of the H1 C-terminal domain within nucleosomes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.11.540398. [PMID: 37214834 PMCID: PMC10197648 DOI: 10.1101/2023.05.11.540398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Despite their importance, how linker histone H1s interact in chromatin and especially how the highly positively charged and intrinsically disordered H1 C-terminal domain (CTD) binds and stabilizes nucleosomes and higher-order chromatin structures remains unclear. Using single-molecule FRET we found that about half of the H1 CTDs in H1-nucleosome complexes exhibit well-defined FRET values indicative of distinct, static conformations, while the remainder of the population exhibits dynamically changing values, similar to that observed for H1 in the absence of nucleosomes. We also find that the first 30 residues of the CTD participate in relatively localized interactions with the first ∼20 bp of linker DNA, and that two separate regions in the CTD contribute to H1-dependent organization of linker DNA, consistent with some non-random CTD-linker DNA interactions. Finally, our data show that acetylation mimetics within the histone H3 tail induce decondensation and enhanced dynamics of the nucleosome-bound H1 CTD. (148 words).
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4
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Louro JA, Boopathi R, Beinsteiner B, Mohideen Patel AK, Cheng TC, Angelov D, Hamiche A, Bendar J, Kale S, Klaholz BP, Dimitrov S. Nucleosome dyad determines the H1 C-terminus collapse on distinct DNA arms. Structure 2023; 31:201-212.e5. [PMID: 36610392 DOI: 10.1016/j.str.2022.12.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 10/19/2022] [Accepted: 12/05/2022] [Indexed: 01/09/2023]
Abstract
Nucleosomes are symmetric structures. However, binding of linker histones generates an inherently asymmetric H1-nucleosome complex, and whether this asymmetry is transmitted to the overall nucleosome structure, and therefore also to chromatin, is unclear. Efforts to investigate potential asymmetry due to H1s have been hampered by the DNA sequence, which naturally differs in each gyre. To overcome this issue, we designed and analyzed by cryo-EM a nucleosome reconstituted with a palindromic (601L) 197-bp DNA. As in the non-palindromic 601 sequence, H1 restricts linker DNA flexibility but reveals partial asymmetrical unwrapping. However, in contrast to the non-palindromic nucleosome, in the palindromic nucleosome H1 CTD collapses to the proximal linker. Molecular dynamics simulations show that this could be dictated by a slightly tilted orientation of the globular domain (GD) of H1, which could be linked to the DNA sequence of the nucleosome dyad.
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Affiliation(s)
- Jaime Alegrio Louro
- Centre for Integrative Biology (CBI), Department of Integrated Structural Biology, IGBMC (Institute of Genetics and of Molecular and Cellular Biology), 1 rue Laurent Fries, 67404 Illkirch, France
| | - Ramachandran Boopathi
- Université Grenoble Alpes, CNRS UMR 5309, INSERM U1209, Institute for Advanced Biosciences (IAB), Site Sante' - Allée des Alpes, 38700 La Tronche, France; Université de Lyon, Ecole Normale Supérieure de Lyon, CNRS, Laboratoire de Biologie et de Modélisation de la Cellule (LBMC), 46 Allée d'Italie, 69007 Lyon, France
| | - Brice Beinsteiner
- Centre for Integrative Biology (CBI), Department of Integrated Structural Biology, IGBMC (Institute of Genetics and of Molecular and Cellular Biology), 1 rue Laurent Fries, 67404 Illkirch, France
| | - Abdul Kareem Mohideen Patel
- Centre for Integrative Biology (CBI), Department of Integrated Structural Biology, IGBMC (Institute of Genetics and of Molecular and Cellular Biology), 1 rue Laurent Fries, 67404 Illkirch, France
| | - Tat Cheung Cheng
- Centre for Integrative Biology (CBI), Department of Integrated Structural Biology, IGBMC (Institute of Genetics and of Molecular and Cellular Biology), 1 rue Laurent Fries, 67404 Illkirch, France
| | - Dimitar Angelov
- Université de Lyon, Ecole Normale Supérieure de Lyon, CNRS, Laboratoire de Biologie et de Modélisation de la Cellule (LBMC), 46 Allée d'Italie, 69007 Lyon, France
| | - Ali Hamiche
- Centre for Integrative Biology (CBI), Department of Integrated Structural Biology, IGBMC (Institute of Genetics and of Molecular and Cellular Biology), 1 rue Laurent Fries, 67404 Illkirch, France; Département de Génomique Fonctionnelle et Cancer, Institut de Génétique et Biologie Moléculaire et Cellulaire (IGBMC)/Université de Strasbourg/CNRS/INSERM, 67404 Illkirch, France
| | - Jan Bendar
- Université Grenoble Alpes, CNRS UMR 5309, INSERM U1209, Institute for Advanced Biosciences (IAB), Site Sante' - Allée des Alpes, 38700 La Tronche, France.
| | - Seyit Kale
- Izmir Biomedicine and Genome Center, Dokuz Eylul University Health Campus, Balçova, 35330 Izmir, Turkey.
| | - Bruno P Klaholz
- Centre for Integrative Biology (CBI), Department of Integrated Structural Biology, IGBMC (Institute of Genetics and of Molecular and Cellular Biology), 1 rue Laurent Fries, 67404 Illkirch, France.
| | - Stefan Dimitrov
- Université Grenoble Alpes, CNRS UMR 5309, INSERM U1209, Institute for Advanced Biosciences (IAB), Site Sante' - Allée des Alpes, 38700 La Tronche, France; Izmir Biomedicine and Genome Center, Dokuz Eylul University Health Campus, Balçova, 35330 Izmir, Turkey.
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5
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Portillo-Ledesma S, Li Z, Schlick T. Genome modeling: From chromatin fibers to genes. Curr Opin Struct Biol 2023; 78:102506. [PMID: 36577295 PMCID: PMC9908845 DOI: 10.1016/j.sbi.2022.102506] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 11/01/2022] [Accepted: 11/06/2022] [Indexed: 12/27/2022]
Abstract
The intricacies of the 3D hierarchical organization of the genome have been approached by many creative modeling studies. The specific model/simulation technique combination defines and restricts the system and phenomena that can be investigated. We present the latest modeling developments and studies of the genome, involving models ranging from nucleosome systems and small polynucleosome arrays to chromatin fibers in the kb-range, chromosomes, and whole genomes, while emphasizing gene folding from first principles. Clever combinations allow the exploration of many interesting phenomena involved in gene regulation, such as nucleosome structure and dynamics, nucleosome-nucleosome stacking, polynucleosome array folding, protein regulation of chromatin architecture, mechanisms of gene folding, loop formation, compartmentalization, and structural transitions at the chromosome and genome levels. Gene-level modeling with full details on nucleosome positions, epigenetic factors, and protein binding, in particular, can in principle be scaled up to model chromosomes and cells to study fundamental biological regulation.
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Affiliation(s)
- Stephanie Portillo-Ledesma
- Department of Chemistry, New York University, 100 Washington Square East, Silver Building, New York, 10003, NY, USA
| | - Zilong Li
- Department of Chemistry, New York University, 100 Washington Square East, Silver Building, New York, 10003, NY, USA
| | - Tamar Schlick
- Department of Chemistry, New York University, 100 Washington Square East, Silver Building, New York, 10003, NY, USA; Courant Institute of Mathematical Sciences, New York University, 251 Mercer St., New York, 10012, NY, USA; New York University-East China Normal University Center for Computational Chemistry, New York University Shanghai, Room 340, Geography Building, 3663 North Zhongshan Road, Shanghai, 200122, China; Simons Center for Computational Physical Chemistry, 24 Waverly Place, Silver Building, New York University, New York, 10003, NY, USA.
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6
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Zhang H, Huo QY, Gao YQ. DNA Sequence-Dependent Binding of Linker Histone gH1 Regulates Nucleosome Conformations. J Phys Chem B 2022; 126:6771-6779. [PMID: 36062461 DOI: 10.1021/acs.jpcb.2c03785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Sequence-dependent binding between DNA and proteins in chromatin is an essential part of gene expression. Linker histone H1 is an important protein in the regulation of chromatin compartmentalization and compaction, and its binding with the nucleosome is sensitive to the DNA sequence. Although the interactions of H1 and DNA have been widely investigated, the mechanism of nucleosome conformation changes induced by the DNA-sequence-dependent binding with gH1 (globular H1.0) remains largely unclear at the atomic level. In the present molecular dynamics simulations, both linker and dyad DNAs were mutated to investigate the conformational changes of the nucleosome induced by the sequence-dependent binding of gH1 based on the on-dyad binding mode. Our results indicate that gH1 is insensitive to the DNA sequence of the dyad DNA but presents an apparent preference to linker DNA with an AT-rich sequence. Moreover, this specific binding induces the entry/exit region of a nucleosome to a tight conformation and regulates the accessibility of core histones. Considering that the entry/exit region of the nucleosome is a crucial binding site for many functional proteins related to gene expression, the conformational change at this region could represent an important gene regulation signal.
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Affiliation(s)
- Hong Zhang
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Qin Yuan Huo
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Yi Qin Gao
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.,Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing 100871, China
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7
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Shi X, Zhai Z, Chen Y, Li J, Nordenskiöld L. Recent Advances in Investigating Functional Dynamics of Chromatin. Front Genet 2022; 13:870640. [PMID: 35450211 PMCID: PMC9017861 DOI: 10.3389/fgene.2022.870640] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 03/11/2022] [Indexed: 11/26/2022] Open
Abstract
Dynamics spanning the picosecond-minute time domain and the atomic-subcellular spatial window have been observed for chromatin in vitro and in vivo. The condensed organization of chromatin in eukaryotic cells prevents regulatory factors from accessing genomic DNA, which requires dynamic stabilization and destabilization of structure to initiate downstream DNA activities. Those processes are achieved through altering conformational and dynamic properties of nucleosomes and nucleosome–protein complexes, of which delineating the atomistic pictures is essential to understand the mechanisms of chromatin regulation. In this review, we summarize recent progress in determining chromatin dynamics and their modulations by a number of factors including post-translational modifications (PTMs), incorporation of histone variants, and binding of effector proteins. We focus on experimental observations obtained using high-resolution techniques, primarily including nuclear magnetic resonance (NMR) spectroscopy, Förster (or fluorescence) resonance energy transfer (FRET) microscopy, and molecular dynamics (MD) simulations, and discuss the elucidated dynamics in the context of functional response and relevance.
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Affiliation(s)
- Xiangyan Shi
- Department of Biology, Shenzhen MSU-BIT University, Shenzhen, China
| | - Ziwei Zhai
- Department of Biology, Shenzhen MSU-BIT University, Shenzhen, China
| | - Yinglu Chen
- Department of Biology, Shenzhen MSU-BIT University, Shenzhen, China
| | - Jindi Li
- Department of Biology, Shenzhen MSU-BIT University, Shenzhen, China
| | - Lars Nordenskiöld
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
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8
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Sanchez-Burgos I, Espinosa JR, Joseph JA, Collepardo-Guevara R. RNA length has a non-trivial effect in the stability of biomolecular condensates formed by RNA-binding proteins. PLoS Comput Biol 2022; 18:e1009810. [PMID: 35108264 PMCID: PMC8896709 DOI: 10.1371/journal.pcbi.1009810] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 03/04/2022] [Accepted: 01/06/2022] [Indexed: 12/29/2022] Open
Abstract
Biomolecular condensates formed via liquid-liquid phase separation (LLPS) play a crucial role in the spatiotemporal organization of the cell material. Nucleic acids can act as critical modulators in the stability of these protein condensates. To unveil the role of RNA length in regulating the stability of RNA binding protein (RBP) condensates, we present a multiscale computational strategy that exploits the advantages of a sequence-dependent coarse-grained representation of proteins and a minimal coarse-grained model wherein proteins are described as patchy colloids. We find that for a constant nucleotide/protein ratio, the protein fused in sarcoma (FUS), which can phase separate on its own-i.e., via homotypic interactions-only exhibits a mild dependency on the RNA strand length. In contrast, the 25-repeat proline-arginine peptide (PR25), which does not undergo LLPS on its own at physiological conditions but instead exhibits complex coacervation with RNA-i.e., via heterotypic interactions-shows a strong dependence on the length of the RNA strands. Our minimal patchy particle simulations suggest that the strikingly different effect of RNA length on homotypic LLPS versus RBP-RNA complex coacervation is general. Phase separation is RNA-length dependent whenever the relative contribution of heterotypic interactions sustaining LLPS is comparable or higher than those stemming from protein homotypic interactions. Taken together, our results contribute to illuminate the intricate physicochemical mechanisms that influence the stability of RBP condensates through RNA inclusion.
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Affiliation(s)
- Ignacio Sanchez-Burgos
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge, United Kingdom
| | - Jorge R. Espinosa
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge, United Kingdom
| | - Jerelle A. Joseph
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge, United Kingdom
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, United Kingdom
- Department of Genetics, University of Cambridge, Downing Site, Cambridge, United Kingdom
| | - Rosana Collepardo-Guevara
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge, United Kingdom
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, United Kingdom
- Department of Genetics, University of Cambridge, Downing Site, Cambridge, United Kingdom
- * E-mail:
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9
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Shukla S, Agarwal P, Kumar A. Disordered regions tune order in chromatin organization and function. Biophys Chem 2022; 281:106716. [PMID: 34844028 DOI: 10.1016/j.bpc.2021.106716] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 11/10/2021] [Accepted: 11/10/2021] [Indexed: 12/29/2022]
Abstract
Intrinsically disordered proteins or hybrid proteins with ordered domains and disordered regions (both collectively designated as IDP(R)s) defy the well-established structure-function paradigm due to their ability to perform multiple biological functions even in the absence of a well-defined 3D structure. IDP(R)s have a unique ability to exist as a functional heterogeneous ensemble, where they adopt multiple thermodynamically stable conformations with low energy barriers between states. The resultant structural plasticity or conformational adaptability provides them with a high functional diversity and ease of regulation. Hence, IDP(R)s are highly efficient biological machinery to mediate intricate cellular functions such as signaling, gene expression, and assembly of complex structures. One such structure is the nucleoprotein complex known as Chromatin. Interestingly, the proteins involved in shaping up the structure and function of chromatin are abundant in disordered regions, which serve more than just as mere flexible linkers. The disordered regions are involved in crucial processes such as gene expression regulation, chromatin architecture maintenance, and liquid-liquid phase separation initiation. This review is an attempt to explore the advantages and the functional and regulatory roles of intrinsic disorder in several Chromatin Associated Proteins from a mechanistic standpoint.
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Affiliation(s)
- Shivangi Shukla
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Prakhar Agarwal
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Ashutosh Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India.
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10
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Unraveling linker histone interactions in nucleosomes. Curr Opin Struct Biol 2021; 71:87-93. [PMID: 34246862 DOI: 10.1016/j.sbi.2021.06.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 06/02/2021] [Indexed: 11/23/2022]
Abstract
Considerable progress has been made recently in defining the interactions of linker histones (H1s) within nucleosomes. Major advancements include atomic resolution structures of the globular domain of full-length H1s in the context of nucleosomes containing full-length linker DNA. Although these studies have led to a detailed understanding of the interactions and dynamics of H1 globular domains in the canonical on-dyad nucleosome binding pocket, more information regarding the intrinsically disordered N-terminal and C-terminal domains is needed. In this review, we highlight studies supporting our current understanding of the structures and interactions of the N-terminal, globular, and C-terminal domains of linker histones within the nucleosome.
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11
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Röder K. Is the H4 histone tail intrinsically disordered or intrinsically multifunctional? Phys Chem Chem Phys 2021; 23:5134-5142. [PMID: 33624669 DOI: 10.1039/d0cp05405d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The structural versatility of histone tails is one of the key elements in the organisation of chromatin, which allows for the compact storage of genomic information. However, this structural diversity also complicates experimental and computational studies. Here, the potential and free energy landscape for the isolated and bound H4 histone tail are explored. The landscapes exhibit a set of distinct structural ensembles separated by high energy barriers, with little difference between isolated and bound tails. This consistency is a desirable feature that facilitates the formation of transient interactions, which are required for the liquid-like chromatin organisation. The existence of multiple, distinct structures on a multifunnel energy landscape is likely to be associated with multifunctionality, i.e. a set of evolved, distinct functions. Contrasting it with previously reported results for other disordered peptides, this type of landscape may be associated with a conformational selection based binding mechanism. Given the similarity to other systems exhibiting similar multifunnel energy landscapes, the disorder in histone tails might be better described in context of multifunctionality.
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Affiliation(s)
- Konstantin Röder
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
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12
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Peng Y, Li S, Landsman D, Panchenko AR. Histone tails as signaling antennas of chromatin. Curr Opin Struct Biol 2021; 67:153-160. [PMID: 33279866 PMCID: PMC8096652 DOI: 10.1016/j.sbi.2020.10.018] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 10/07/2020] [Accepted: 10/18/2020] [Indexed: 12/19/2022]
Abstract
Histone tails, representing the N-terminal or C-terminal regions flanking the histone core, play essential roles in chromatin signaling networks. Intrinsic disorder of histone tails and their propensity for post-translational modifications allow them to serve as hubs in coordination of epigenetic processes within the nucleosomal context. Deposition of histone variants with distinct histone tail properties further enriches histone tails' repertoire in epigenetic signaling. Given the advances in experimental techniques and in silico modelling, we review the most recent data on histone tails' effects on nucleosome stability and dynamics, their function in regulating chromatin accessibility and folding. Finally, we discuss different molecular mechanisms to understand how histone tails are involved in nucleosome recognition by binding partners and formation of higher-order chromatin structures.
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Affiliation(s)
- Yunhui Peng
- National Center for Biotechnology Information, National Institutes of Health, Bethesda, MD, USA
| | - Shuxiang Li
- Department of Pathology and Molecular Medicine, School of Medicine, Queen's University, ON, Canada
| | - David Landsman
- National Center for Biotechnology Information, National Institutes of Health, Bethesda, MD, USA
| | - Anna R Panchenko
- Department of Pathology and Molecular Medicine, School of Medicine, Queen's University, ON, Canada.
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13
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Lobbia VR, Trueba Sanchez MC, van Ingen H. Beyond the Nucleosome: Nucleosome-Protein Interactions and Higher Order Chromatin Structure. J Mol Biol 2021; 433:166827. [PMID: 33460684 DOI: 10.1016/j.jmb.2021.166827] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/05/2021] [Accepted: 01/06/2021] [Indexed: 12/20/2022]
Abstract
The regulation of chromatin biology ultimately depends on the manipulation of its smallest subunit, the nucleosome. The proteins that bind and operate on the nucleosome do so, while their substrate is part of a polymer embedded in the dense nuclear environment. Their molecular interactions must in some way be tuned to deal with this complexity. Due to the rapid increase in the number of high-resolution structures of nucleosome-protein complexes and the increasing understanding of the cellular chromatin structure, it is starting to become clearer how chromatin factors operate in this complex environment. In this review, we analyze the current literature on the interplay between nucleosome-protein interactions and higher-order chromatin structure. We examine in what way nucleosomes-protein interactions can affect and can be affected by chromatin organization at the oligonucleosomal level. In addition, we review the characteristics of nucleosome-protein interactions that can cause phase separation of chromatin. Throughout, we hope to illustrate the exciting challenges in characterizing nucleosome-protein interactions beyond the nucleosome.
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Affiliation(s)
- Vincenzo R Lobbia
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
| | - Maria Cristina Trueba Sanchez
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
| | - Hugo van Ingen
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands.
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Fatafta H, Samantray S, Sayyed-Ahmad A, Coskuner-Weber O, Strodel B. Molecular simulations of IDPs: From ensemble generation to IDP interactions leading to disorder-to-order transitions. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2021; 183:135-185. [PMID: 34656328 DOI: 10.1016/bs.pmbts.2021.06.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/26/2023]
Abstract
Intrinsically disordered proteins (IDPs) lack a well-defined three-dimensional structure but do exhibit some dynamical and structural ordering. The structural plasticity of IDPs indicates that entropy-driven motions are crucial for their function. Many IDPs undergo function-related disorder-to-order transitions upon by their interaction with specific binding partners. Approaches that are based on both experimental and theoretical tools enable the biophysical characterization of IDPs. Molecular simulations provide insights into IDP structural ensembles and disorder-to-order transition mechanisms. However, such studies depend strongly on the chosen force field parameters and simulation techniques. In this chapter, we provide an overview of IDP characteristics, review all-atom force fields recently developed for IDPs, and present molecular dynamics-based simulation methods that allow IDP ensemble generation as well as the characterization of disorder-to-order transitions. In particular, we introduce metadynamics, replica exchange molecular dynamics simulations, and also kinetic models resulting from Markov State modeling, and provide various examples for the successful application of these simulation methods to IDPs.
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Affiliation(s)
- Hebah Fatafta
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, Jülich, Germany
| | - Suman Samantray
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, Jülich, Germany; AICES Graduate School, RWTH Aachen University, Aachen, Germany
| | | | - Orkid Coskuner-Weber
- Molecular Biotechnology, Turkish-German University, Sahinkaya Caddesi, Istanbul, Turkey
| | - Birgit Strodel
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, Jülich, Germany; Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
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Huertas J, Cojocaru V. Breaths, Twists, and Turns of Atomistic Nucleosomes. J Mol Biol 2020; 433:166744. [PMID: 33309853 DOI: 10.1016/j.jmb.2020.166744] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 12/02/2020] [Accepted: 12/02/2020] [Indexed: 02/07/2023]
Abstract
Gene regulation programs establish cellular identity and rely on dynamic changes in the structural packaging of genomic DNA. The DNA is packaged in chromatin, which is formed from arrays of nucleosomes displaying different degree of compaction and different lengths of inter-nucleosomal linker DNA. The nucleosome represents the repetitive unit of chromatin and is formed by wrapping 145-147 basepairs of DNA around an octamer of histone proteins. Each of the four histones is present twice and has a structured core and intrinsically disordered terminal tails. Chromatin dynamics are triggered by inter- and intra-nucleosome motions that are controlled by the DNA sequence, the interactions between the histone core and the DNA, and the conformations, positions, and DNA interactions of the histone tails. Understanding chromatin dynamics requires studying all these features at the highest possible resolution. For this, molecular dynamics simulations can be used as a powerful complement or alternative to experimental approaches, from which it is often very challenging to characterize the structural features and atomic interactions controlling nucleosome motions. Molecular dynamics simulations can be performed at different resolutions, by coarse graining the molecular system with varying levels of details. Here we review the successes and the remaining challenges of the application of atomic resolution simulations to study the structure and dynamics of nucleosomes and their complexes with interacting partners.
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Affiliation(s)
- Jan Huertas
- In Silico Biomolecular Structure and Dynamics Group, Hubrecht Institute, Utrecht, the Netherlands; Department of Cellular and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany; Center for Multiscale Theory and Computation, Westfälische Wilhelms University, Münster, Germany
| | - Vlad Cojocaru
- In Silico Biomolecular Structure and Dynamics Group, Hubrecht Institute, Utrecht, the Netherlands; Department of Cellular and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany; Center for Multiscale Theory and Computation, Westfälische Wilhelms University, Münster, Germany.
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Hernández-Segura T, Pastor N. Identification of an α-MoRF in the Intrinsically Disordered Region of the Escargot Transcription Factor. ACS OMEGA 2020; 5:18331-18341. [PMID: 32743208 PMCID: PMC7392517 DOI: 10.1021/acsomega.0c02051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Accepted: 07/02/2020] [Indexed: 06/11/2023]
Abstract
Molecular recognition features (MoRFs) are common in intrinsically disordered proteins (IDPs) and intrinsically disordered regions (IDRs). MoRFs are in constant order-disorder structural transitions and adopt well-defined structures once they are bound to their targets. Here, we study Escargot (Esg), a transcription factor in Drosophila melanogaster that regulates multiple cellular functions, and consists of a disordered N-terminal domain and a group of zinc fingers at its C-terminal domain. We analyzed the N-terminal domain of Esg with disorder predictors and identified a region of 45 amino acids with high probability to form ordered structures, which we named S2. Through 54 μs of molecular dynamics (MD) simulations using CHARMM36 and implicit solvent (generalized Born/surface area (GBSA)), we characterized the conformational landscape of S2 and found an α-MoRF of ∼16 amino acids stabilized by key contacts within the helix. To test the importance of these contacts in the stability of the α-MoRF, we evaluated the effect of point mutations that would impair these interactions, running 24 μs of MD for each mutation. The mutations had mild effects on the MoRF, and in some cases, led to gain of residual structure through long-range contacts of the α-MoRF and the rest of the S2 region. As this could be an effect of the force field and solvent model we used, we benchmarked our simulation protocol by carrying out 32 μs of MD for the (AAQAA)3 peptide. The results of the benchmark indicate that the global amount of helix in shorter peptides like (AAQAA)3 is reasonably predicted. Careful analysis of the runs of S2 and its mutants suggests that the mutation to hydrophobic residues may have nucleated long-range hydrophobic and aromatic interactions that stabilize the MoRF. Finally, we have identified a set of residues that stabilize an α-MoRF in a region still without functional annotations in Esg.
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Affiliation(s)
- Teresa Hernández-Segura
- Laboratorio
de Dinámica de Proteínas, Centro de Investigación
en Dinámica Celular-IICBA, Universidad
Autónoma del Estado de Morelos, Av. Universidad 1001, Chamilpa, 62209 Cuernavaca, México
- Doctorado
en Ciencias CIDC-IICBA, Universidad Autónoma
del Estado de Morelos, Cuernavaca 62209, Morelos, México
| | - Nina Pastor
- Laboratorio
de Dinámica de Proteínas, Centro de Investigación
en Dinámica Celular-IICBA, Universidad
Autónoma del Estado de Morelos, Av. Universidad 1001, Chamilpa, 62209 Cuernavaca, México
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