1
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Roldán-Piñero C, Luengo-Márquez J, Assenza S, Pérez R. Systematic Comparison of Atomistic Force Fields for the Mechanical Properties of Double-Stranded DNA. J Chem Theory Comput 2024; 20:2261-2272. [PMID: 38411091 PMCID: PMC10938644 DOI: 10.1021/acs.jctc.3c01089] [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: 10/02/2023] [Revised: 02/14/2024] [Accepted: 02/14/2024] [Indexed: 02/28/2024]
Abstract
The response of double-stranded DNA to external mechanical stress plays a central role in its interactions with the protein machinery in the cell. Modern atomistic force fields have been shown to provide highly accurate predictions for the fine structural features of the duplex. In contrast, and despite their pivotal function, less attention has been devoted to the accuracy of the prediction of the elastic parameters. Several reports have addressed the flexibility of double-stranded DNA via all-atom molecular dynamics, yet the collected information is insufficient to have a clear understanding of the relative performance of the various force fields. In this work, we fill this gap by performing a systematic study in which several systems, characterized by different sequence contexts, are simulated with the most popular force fields within the AMBER family, bcs1 and OL15, as well as with CHARMM36. Analysis of our results, together with their comparison with previous work focused on bsc0, allows us to unveil the differences in the predicted rigidity between the newest force fields and suggests a roadmap to test their performance against experiments. In the case of the stretch modulus, we reconcile these differences, showing that a single mapping between sequence-dependent conformation and elasticity via the crookedness parameter captures simultaneously the results of all force fields, supporting the key role of crookedness in the mechanical response of double-stranded DNA.
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Affiliation(s)
- Carlos Roldán-Piñero
- Departamento
de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Juan Luengo-Márquez
- Departamento
de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto
Nicolás Cabrera, Universidad Autónoma
de Madrid, E-28049 Madrid, Spain
| | - Salvatore Assenza
- Departamento
de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto
Nicolás Cabrera, Universidad Autónoma
de Madrid, E-28049 Madrid, Spain
- Condensed
Matter Physics Center (IFIMAC), Universidad
Autónoma de Madrid, E-28049 Madrid, Spain
| | - Rubén Pérez
- Departamento
de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed
Matter Physics Center (IFIMAC), Universidad
Autónoma de Madrid, E-28049 Madrid, Spain
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2
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Sutormin D, Galivondzhyan A, Gafurov A, Severinov K. Single-nucleotide resolution detection of Topo IV cleavage activity in the Escherichia coli genome with Topo-Seq. Front Microbiol 2023; 14:1160736. [PMID: 37089538 PMCID: PMC10117906 DOI: 10.3389/fmicb.2023.1160736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 03/16/2023] [Indexed: 04/08/2023] Open
Abstract
Topoisomerase IV (Topo IV) is the main decatenation enzyme in Escherichia coli; it removes catenation links that are formed during DNA replication. Topo IV binding and cleavage sites were previously identified in the E. coli genome with ChIP-Seq and NorfIP. Here, we used a more sensitive, single-nucleotide resolution Topo-Seq procedure to identify Topo IV cleavage sites (TCSs) genome-wide. We detected thousands of TCSs scattered in the bacterial genome. The determined cleavage motif of Topo IV contained previously known cleavage determinants (−4G/+8C, −2A/+6 T, −1 T/+5A) and additional, not observed previously, positions −7C/+11G and −6C/+10G. TCSs were depleted in the Ter macrodomain except for two exceptionally strong non-canonical cleavage sites located in 33 and 38 bp from the XerC-box of the dif-site. Topo IV cleavage activity was increased in Left and Right macrodomains flanking the Ter macrodomain and was especially high in the 50–60 kb region containing the oriC origin of replication. Topo IV enrichment was also increased downstream of highly active transcription units, indicating that the enzyme is involved in relaxation of transcription-induced positive supercoiling.
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Affiliation(s)
- Dmitry Sutormin
- Skolkovo Institute of Science and Technology, Moscow, Russia
- *Correspondence: Dmitry Sutormin,
| | | | - Azamat Gafurov
- Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Konstantin Severinov
- Waksman Institute for Microbiology, Rutgers, The State University of New Jersey, Piscataway, NJ, United States
- Konstantin Severinov,
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3
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Japaridze A, van Wee R, Gogou C, Kerssemakers JWJ, van den Berg DF, Dekker C. MukBEF-dependent chromosomal organization in widened Escherichia coli. Front Microbiol 2023; 14:1107093. [PMID: 36937278 PMCID: PMC10020239 DOI: 10.3389/fmicb.2023.1107093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 02/03/2023] [Indexed: 03/06/2023] Open
Abstract
The bacterial chromosome is spatially organized through protein-mediated compaction, supercoiling, and cell-boundary confinement. Structural Maintenance of Chromosomes (SMC) complexes are a major class of chromosome-organizing proteins present throughout all domains of life. Here, we study the role of the Escherichia coli SMC complex MukBEF in chromosome architecture and segregation. Using quantitative live-cell imaging of shape-manipulated cells, we show that MukBEF is crucial to preserve the toroidal topology of the Escherichia coli chromosome and that it is non-uniformly distributed along the chromosome: it prefers locations toward the origin and away from the terminus of replication, and it is unevenly distributed over the origin of replication along the two chromosome arms. Using an ATP hydrolysis-deficient MukB mutant, we confirm that MukBEF translocation along the chromosome is ATP-dependent, in contrast to its loading onto DNA. MukBEF and MatP are furthermore found to be essential for sister chromosome decatenation. We propose a model that explains how MukBEF, MatP, and their interacting partners organize the chromosome and contribute to sister segregation. The combination of bacterial cell-shape modification and quantitative fluorescence microscopy paves way to investigating chromosome-organization factors in vivo.
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4
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Assenza S, Pérez R. Accurate Sequence-Dependent Coarse-Grained Model for Conformational and Elastic Properties of Double-Stranded DNA. J Chem Theory Comput 2022; 18:3239-3256. [PMID: 35394775 PMCID: PMC9097290 DOI: 10.1021/acs.jctc.2c00138] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
![]()
We introduce MADna,
a sequence-dependent coarse-grained model of
double-stranded DNA (dsDNA), where each nucleotide is described by
three beads localized at the sugar, at the base moiety, and at the
phosphate group, respectively. The sequence dependence is included
by considering a step-dependent parametrization of the bonded interactions,
which are tuned in order to reproduce the values of key observables
obtained from exhaustive atomistic simulations from the literature.
The predictions of the model are benchmarked against an independent
set of all-atom simulations, showing that it captures with high fidelity
the sequence dependence of conformational and elastic features beyond
the single step considered in its formulation. A remarkably good agreement
with experiments is found for both sequence-averaged and sequence-dependent
conformational and elastic features, including the stretching and
torsion moduli, the twist–stretch and twist–bend couplings,
the persistence length, and the helical pitch. Overall, for the inspected
quantities, the model has a precision comparable to atomistic simulations,
hence providing a reliable coarse-grained description for the rationalization
of single-molecule experiments and the study of cellular processes
involving dsDNA. Owing to the simplicity of its formulation, MADna
can be straightforwardly included in common simulation engines. Particularly,
an implementation of the model in LAMMPS is made available on an online
repository to ease its usage within the DNA research community.
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5
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Duplex DNA and BLM regulate gate opening by the human TopoIIIα-RMI1-RMI2 complex. Nat Commun 2022; 13:584. [PMID: 35102151 PMCID: PMC8803869 DOI: 10.1038/s41467-022-28082-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 01/10/2022] [Indexed: 12/31/2022] Open
Abstract
Topoisomerase IIIα is a type 1A topoisomerase that forms a complex with RMI1 and RMI2 called TRR in human cells. TRR plays an essential role in resolving DNA replication and recombination intermediates, often alongside the helicase BLM. While the TRR catalytic cycle is known to involve a protein-mediated single-stranded (ss)DNA gate, the detailed mechanism is not fully understood. Here, we probe the catalytic steps of TRR using optical tweezers and fluorescence microscopy. We demonstrate that TRR forms an open gate in ssDNA of 8.5 ± 3.8 nm, and directly visualize binding of a second ssDNA or double-stranded (ds)DNA molecule to the open TRR-ssDNA gate, followed by catenation in each case. Strikingly, dsDNA binding increases the gate size (by ~16%), while BLM alters the mechanical flexibility of the gate. These findings reveal an unexpected plasticity of the TRR-ssDNA gate size and suggest that TRR-mediated transfer of dsDNA may be more relevant in vivo than previously believed. Here the authors probe the cleavage and gate opening of single-stranded DNA by the human topoisomerase TRR using a unique single-molecule strategy to reveal structural plasticity in response to both double-stranded DNA and the helicase BLM.
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6
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Bell NAW, Haynes PJ, Brunner K, de Oliveira TM, Flocco MM, Hoogenboom BW, Molloy JE. Single-molecule measurements reveal that PARP1 condenses DNA by loop stabilization. SCIENCE ADVANCES 2021; 7:7/33/eabf3641. [PMID: 34380612 PMCID: PMC8357241 DOI: 10.1126/sciadv.abf3641] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 06/22/2021] [Indexed: 05/11/2023]
Abstract
Poly(ADP-ribose) polymerase 1 (PARP1) is an abundant nuclear enzyme that plays important roles in DNA repair, chromatin organization and transcription regulation. Although binding and activation of PARP1 by DNA damage sites has been extensively studied, little is known about how PARP1 binds to long stretches of undamaged DNA and how it could shape chromatin architecture. Here, using single-molecule techniques, we show that PARP1 binds and condenses undamaged, kilobase-length DNA subject to sub-piconewton mechanical forces. Stepwise decondensation at high force and DNA braiding experiments show that the condensation activity is due to the stabilization of DNA loops by PARP1. PARP inhibitors do not affect the level of condensation of undamaged DNA but act to block condensation reversal for damaged DNA in the presence of NAD+ Our findings suggest a mechanism for PARP1 in the organization of chromatin structure.
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Affiliation(s)
- Nicholas A W Bell
- The Francis Crick Institute, London NW1 1AT, UK.
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK
| | - Philip J Haynes
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK
- Molecular Sciences Research Hub, Department of Chemistry, Imperial College London, London W12 0BZ, UK
- Department of Physics and Astronomy, University College London, London WC1E 6BT, UK
| | - Katharina Brunner
- The Francis Crick Institute, London NW1 1AT, UK
- Discovery Biology, Discovery Sciences, R&D, AstraZeneca, Cambridge, UK
| | - Taiana Maia de Oliveira
- Mechanistic and Structural Biology, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Maria M Flocco
- Mechanistic and Structural Biology, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Bart W Hoogenboom
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK
- Department of Physics and Astronomy, University College London, London WC1E 6BT, UK
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7
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Spakman D, Bakx JAM, Biebricher AS, Peterman EJG, Wuite GJL, King GA. Unravelling the mechanisms of Type 1A topoisomerases using single-molecule approaches. Nucleic Acids Res 2021; 49:5470-5492. [PMID: 33963870 PMCID: PMC8191776 DOI: 10.1093/nar/gkab239] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 03/19/2021] [Accepted: 05/05/2021] [Indexed: 12/14/2022] Open
Abstract
Topoisomerases are essential enzymes that regulate DNA topology. Type 1A family topoisomerases are found in nearly all living organisms and are unique in that they require single-stranded (ss)DNA for activity. These enzymes are vital for maintaining supercoiling homeostasis and resolving DNA entanglements generated during DNA replication and repair. While the catalytic cycle of Type 1A topoisomerases has been long-known to involve an enzyme-bridged ssDNA gate that allows strand passage, a deeper mechanistic understanding of these enzymes has only recently begun to emerge. This knowledge has been greatly enhanced through the combination of biochemical studies and increasingly sophisticated single-molecule assays based on magnetic tweezers, optical tweezers, atomic force microscopy and Förster resonance energy transfer. In this review, we discuss how single-molecule assays have advanced our understanding of the gate opening dynamics and strand-passage mechanisms of Type 1A topoisomerases, as well as the interplay of Type 1A topoisomerases with partner proteins, such as RecQ-family helicases. We also highlight how these assays have shed new light on the likely functional roles of Type 1A topoisomerases in vivo and discuss recent developments in single-molecule technologies that could be applied to further enhance our understanding of these essential enzymes.
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Affiliation(s)
- Dian Spakman
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Julia A M Bakx
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Andreas S Biebricher
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Erwin J G Peterman
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Gijs J L Wuite
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Graeme A King
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK
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8
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Gogou C, Japaridze A, Dekker C. Mechanisms for Chromosome Segregation in Bacteria. Front Microbiol 2021; 12:685687. [PMID: 34220773 PMCID: PMC8242196 DOI: 10.3389/fmicb.2021.685687] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 05/19/2021] [Indexed: 11/13/2022] Open
Abstract
The process of DNA segregation, the redistribution of newly replicated genomic material to daughter cells, is a crucial step in the life cycle of all living systems. Here, we review DNA segregation in bacteria which evolved a variety of mechanisms for partitioning newly replicated DNA. Bacterial species such as Caulobacter crescentus and Bacillus subtilis contain pushing and pulling mechanisms that exert forces and directionality to mediate the moving of newly synthesized chromosomes to the bacterial poles. Other bacteria such as Escherichia coli lack such active segregation systems, yet exhibit a spontaneous de-mixing of chromosomes due to entropic forces as DNA is being replicated under the confinement of the cell wall. Furthermore, we present a synopsis of the main players that contribute to prokaryotic genome segregation. We finish with emphasizing the importance of bottom-up approaches for the investigation of the various factors that contribute to genome segregation.
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Affiliation(s)
- Christos Gogou
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, Netherlands
| | - Aleksandre Japaridze
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, Netherlands
| | - Cees Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, Netherlands
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9
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DNA-Topology Simplification by Topoisomerases. Molecules 2021; 26:molecules26113375. [PMID: 34204901 PMCID: PMC8199745 DOI: 10.3390/molecules26113375] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/20/2021] [Accepted: 05/26/2021] [Indexed: 11/17/2022] Open
Abstract
The topological properties of DNA molecules, supercoiling, knotting, and catenation, are intimately connected with essential biological processes, such as gene expression, replication, recombination, and chromosome segregation. Non-trivial DNA topologies present challenges to the molecular machines that process and maintain genomic information, for example, by creating unwanted DNA entanglements. At the same time, topological distortion can facilitate DNA-sequence recognition through localized duplex unwinding and longer-range loop-mediated interactions between the DNA sequences. Topoisomerases are a special class of essential enzymes that homeostatically manage DNA topology through the passage of DNA strands. The activities of these enzymes are generally investigated using circular DNA as a model system, in which case it is possible to directly assay the formation and relaxation of DNA supercoils and the formation/resolution of knots and catenanes. Some topoisomerases use ATP as an energy cofactor, whereas others act in an ATP-independent manner. The free energy of ATP hydrolysis can be used to drive negative and positive supercoiling or to specifically relax DNA topologies to levels below those that are expected at thermodynamic equilibrium. The latter activity, which is known as topology simplification, is thus far exclusively associated with type-II topoisomerases and it can be understood through insight into the detailed non-equilibrium behavior of type-II enzymes. We use a non-equilibrium topological-network approach, which stands in contrast to the equilibrium models that are conventionally used in the DNA-topology field, to gain insights into the rates that govern individual transitions between topological states. We anticipate that our quantitative approach will stimulate experimental work and the theoretical/computational modeling of topoisomerases and similar enzyme systems.
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10
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Sutormin DA, Galivondzhyan AK, Polkhovskiy AV, Kamalyan SO, Severinov KV, Dubiley SA. Diversity and Functions of Type II Topoisomerases. Acta Naturae 2021; 13:59-75. [PMID: 33959387 PMCID: PMC8084294 DOI: 10.32607/actanaturae.11058] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 10/09/2020] [Indexed: 11/29/2022] Open
Abstract
The DNA double helix provides a simple and elegant way to store and copy genetic information. However, the processes requiring the DNA helix strands separation, such as transcription and replication, induce a topological side-effect - supercoiling of the molecule. Topoisomerases comprise a specific group of enzymes that disentangle the topological challenges associated with DNA supercoiling. They relax DNA supercoils and resolve catenanes and knots. Here, we review the catalytic cycles, evolution, diversity, and functional roles of type II topoisomerases in organisms from all domains of life, as well as viruses and other mobile genetic elements.
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Affiliation(s)
- D. A. Sutormin
- Institute of Gene Biology RAS, Moscow, 119334 Russia
- Centre for Life Sciences, Skolkovo Institute of Science and Technology, Moscow, 121205 Russia
| | - A. K. Galivondzhyan
- Lomonosov Moscow State University, Moscow, 119991 Russia
- Institute of Molecular Genetics RAS, Moscow, 123182 Russia
| | - A. V. Polkhovskiy
- Institute of Gene Biology RAS, Moscow, 119334 Russia
- Centre for Life Sciences, Skolkovo Institute of Science and Technology, Moscow, 121205 Russia
| | - S. O. Kamalyan
- Institute of Gene Biology RAS, Moscow, 119334 Russia
- Centre for Life Sciences, Skolkovo Institute of Science and Technology, Moscow, 121205 Russia
| | - K. V. Severinov
- Centre for Life Sciences, Skolkovo Institute of Science and Technology, Moscow, 121205 Russia
- Centre for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology RAS, Moscow, 119334 Russia
- Waksman Institute for Microbiology, Piscataway, New Jersey, 08854 USA
| | - S. A. Dubiley
- Institute of Gene Biology RAS, Moscow, 119334 Russia
- Centre for Life Sciences, Skolkovo Institute of Science and Technology, Moscow, 121205 Russia
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11
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Kota S, Chaudhary R, Mishra S, Misra HS. Topoisomerase IB interacts with genome segregation proteins and is involved in multipartite genome maintenance in Deinococcus radiodurans. Microbiol Res 2020; 242:126609. [PMID: 33059113 DOI: 10.1016/j.micres.2020.126609] [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] [Received: 05/02/2020] [Revised: 09/18/2020] [Accepted: 09/19/2020] [Indexed: 10/23/2022]
Abstract
Deinococcus radiodurans, an extremophile, resistant to many abiotic stresses including ionizing radiation, has 2 type I topoisomerases (drTopo IA and drTopo IB) and one type II topoisomerase (DNA gyrase). The role of drTopo IB in guanine quadruplex DNA (G4 DNA) metabolism was demonstrated earlier in vitro. Here, we report that D. radiodurans cells lacking drTopo IB (ΔtopoIB) show sensitivity to G4 DNA binding drug (NMM) under normal growth conditions. The activity of G4 motif containing promoters like mutL and recQ was reduced in the presence of NMM in mutant cells. In mutant, the percentage of anucleate cells was more while the copy number of genome elements were less as compared to wild type. Protein-protein interaction studies showed that drTopo IB interacts with genome segregation and DNA replication initiation (DnaA) proteins. The typical patterns of cellular localization of GFP-PprA were affected in the mutant cells. Microscopic examination of D. radiodurans cells expressing drTopo IB-RFP showed its localization on nucleoid forming a streak parallel to the old division septum and perpendicular to newly formed septum. These results together suggest the role of drTopo IB in genome maintenance in this bacterium.
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Affiliation(s)
- Swathi Kota
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, 400085, India; Life Sciences, Homi Bhabha National Institute, Mumbai, 400094, India.
| | - Reema Chaudhary
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, 400085, India; Life Sciences, Homi Bhabha National Institute, Mumbai, 400094, India
| | - Shruti Mishra
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, 400085, India; Life Sciences, Homi Bhabha National Institute, Mumbai, 400094, India
| | - Hari S Misra
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, 400085, India; Life Sciences, Homi Bhabha National Institute, Mumbai, 400094, India.
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12
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Ziraldo R, Hanke A, Levene SD. Kinetic pathways of topology simplification by Type-II topoisomerases in knotted supercoiled DNA. Nucleic Acids Res 2019; 47:69-84. [PMID: 30476194 PMCID: PMC6326819 DOI: 10.1093/nar/gky1174] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 11/02/2018] [Indexed: 11/13/2022] Open
Abstract
The topological state of covalently closed, double-stranded DNA is defined by the knot type $K$ and the linking-number difference $\Delta Lk$ relative to unknotted relaxed DNA. DNA topoisomerases are essential enzymes that control the topology of DNA in all cells. In particular, type-II topoisomerases change both $K$ and $\Delta Lk$ by a duplex-strand-passage mechanism and have been shown to simplify the topology of DNA to levels below thermal equilibrium at the expense of ATP hydrolysis. It remains a key question how small enzymes are able to preferentially select strand passages that result in topology simplification in much larger DNA molecules. Using numerical simulations, we consider the non-equilibrium dynamics of transitions between topological states $(K,\Delta Lk)$ in DNA induced by type-II topoisomerases. For a biological process that delivers DNA molecules in a given topological state $(K,\Delta Lk)$ at a constant rate we fully characterize the pathways of topology simplification by type-II topoisomerases in terms of stationary probability distributions and probability currents on the network of topological states $(K,\Delta Lk)$. In particular, we observe that type-II topoisomerase activity is significantly enhanced in DNA molecules that maintain a supercoiled state with constant torsional tension. This is relevant for bacterial cells in which torsional tension is maintained by enzyme-dependent homeostatic mechanisms such as DNA-gyrase activity.
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Affiliation(s)
- Riccardo Ziraldo
- Department of Bioengineering, University of Texas at Dallas, TX 75080, USA
| | - Andreas Hanke
- Department of Physics and Astronomy, University of Texas Rio Grande Valley, Brownsville, TX 78520, USA
| | - Stephen D Levene
- Department of Bioengineering, University of Texas at Dallas, TX 75080, USA.,Department of Biological Sciences, University of Texas at Dallas, Richardson, TX 75080, USA.,Department of Physics, University of Texas at Dallas, Richardson, TX 75080, USA
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13
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Rani P, Nagaraja V. Genome-wide mapping of Topoisomerase I activity sites reveal its role in chromosome segregation. Nucleic Acids Res 2019; 47:1416-1427. [PMID: 30566665 PMCID: PMC6379724 DOI: 10.1093/nar/gky1271] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 11/30/2018] [Accepted: 12/13/2018] [Indexed: 11/13/2022] Open
Abstract
DNA Topoisomerase I (TopoI) in eubacteria is the principle DNA relaxase, belonging to Type 1A group. The enzyme from Mycobacterium smegmatis is essential for cell survival and distinct from other eubacteria in having several unusual characteristics. To understand genome-wide TopoI engagements in vivo, functional sites were mapped by employing a poisonous variant of the enzyme and a newly discovered inhibitor, both of which arrest the enzyme activity after the first transestrification reaction, thereby leading to the accumulation of protein-DNA covalent complexes. The cleavage sites are subsets of TopoI binding sites, implying that TopoI recruitment does not necessarily lead to DNA cleavage in vivo. The cleavage protection conferred by nucleoid associated proteins in vitro suggest a similar possibility in vivo. Co-localization of binding and cleavage sites of the enzyme on transcription units, implying that both TopoI recruitment and function are associated with active transcription. Attenuation of the cleavage upon Rifampicin treatment confirms the close connection between transcription and TopoI action. Notably, TopoI is inactive upstream of the Transcription start site (TSS) and activated following transcription initiation. The binding of TopoI at the Ter region, and the DNA cleavage at the Ter indicates TopoI involvement in chromosome segregation, substantiated by its catenation and decatenation activities.
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Affiliation(s)
- Phoolwanti Rani
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India.,Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
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14
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Abstract
We review the current understanding of the mechanics of DNA and DNA-protein complexes, from scales of base pairs up to whole chromosomes. Mechanics of the double helix as revealed by single-molecule experiments will be described, with an emphasis on the role of polymer statistical mechanics. We will then discuss how topological constraints- entanglement and supercoiling-impact physical and mechanical responses. Models for protein-DNA interactions, including effects on polymer properties of DNA of DNA-bending proteins will be described, relevant to behavior of protein-DNA complexes in vivo. We also discuss control of DNA entanglement topology by DNA-lengthwise-compaction machinery acting in concert with topoisomerases. Finally, the chapter will conclude with a discussion of relevance of several aspects of physical properties of DNA and chromatin to oncology.
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15
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Reuß DR, Faßhauer P, Mroch PJ, Ul-Haq I, Koo BM, Pöhlein A, Gross CA, Daniel R, Brantl S, Stülke J. Topoisomerase IV can functionally replace all type 1A topoisomerases in Bacillus subtilis. Nucleic Acids Res 2019; 47:5231-5242. [PMID: 30957856 PMCID: PMC6547408 DOI: 10.1093/nar/gkz260] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 03/30/2019] [Accepted: 04/01/2019] [Indexed: 12/22/2022] Open
Abstract
DNA topoisomerases play essential roles in chromosome organization and replication. Most bacteria possess multiple topoisomerases which have specialized functions in the control of DNA supercoiling or in DNA catenation/decatenation during recombination and chromosome segregation. DNA topoisomerase I is required for the relaxation of negatively supercoiled DNA behind the transcribing RNA polymerase. Conflicting results have been reported on the essentiality of the topA gene encoding topoisomerase I in the model bacterium Bacillus subtilis. In this work, we have studied the requirement for topoisomerase I in B. subtilis. All stable topA mutants carried different chromosomal amplifications of the genomic region encompassing the parEC operon encoding topoisomerase IV. Using a fluorescent amplification reporter system we observed that each individual topA mutant had acquired such an amplification. Eventually, the amplifications were replaced by a point mutation in the parEC promoter region which resulted in a fivefold increase of parEC expression. In this strain both type I topoisomerases, encoded by topA and topB, were dispensable. Our results demonstrate that topoisomerase IV at increased expression is necessary and sufficient to take over the function of type 1A topoisomerases.
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Affiliation(s)
- Daniel R Reuß
- Department of General Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Patrick Faßhauer
- Department of General Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Philipp Joel Mroch
- Department of General Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Inam Ul-Haq
- Matthias-Schleiden-Institut, AG Bakteriengenetik, Friedrich-Schiller-University Jena, Jena, Germany
| | - Byoung-Mo Koo
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Anja Pöhlein
- Department of Genomic and Applied Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Carol A Gross
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Rolf Daniel
- Department of Genomic and Applied Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Sabine Brantl
- Matthias-Schleiden-Institut, AG Bakteriengenetik, Friedrich-Schiller-University Jena, Jena, Germany
| | - Jörg Stülke
- Department of General Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
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16
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Mills M, Tse-Dinh YC, Neuman KC. Direct observation of topoisomerase IA gate dynamics. Nat Struct Mol Biol 2018; 25:1111-1118. [PMID: 30478267 PMCID: PMC6379066 DOI: 10.1038/s41594-018-0158-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 10/31/2018] [Indexed: 12/18/2022]
Abstract
Type IA topoisomerases cleave single-stranded DNA and relieve negative supercoils in discrete steps corresponding to the passage of the intact DNA strand through the cleaved strand. Although type IA topoisomerases are assumed to accomplish this strand passage via a protein-mediated DNA gate, opening of this gate has never been observed. We developed a single-molecule assay to directly measure gate opening of the Escherichia coli type IA topoisomerases I and III. We found that after cleavage of single-stranded DNA, the protein gate opens by as much as 6.6 nm and can close against forces in excess of 16 pN. Key differences in the cleavage, ligation, and gate dynamics of these two enzymes provide insights into their different cellular functions. The single-molecule results are broadly consistent with conformational changes obtained from molecular dynamics simulations. These results allowed us to develop a mechanistic model of interactions between type IA topoisomerases and single-stranded DNA.
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Affiliation(s)
- Maria Mills
- Laboratory of Single Molecule Biophysics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Yuk-Ching Tse-Dinh
- Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL, USA
| | - Keir C Neuman
- Laboratory of Single Molecule Biophysics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
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17
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Brahmachari S, Gunn KH, Giuntoli RD, Mondragón A, Marko JF. Nucleation of Multiple Buckled Structures in Intertwined DNA Double Helices. PHYSICAL REVIEW LETTERS 2017; 119:188103. [PMID: 29219598 PMCID: PMC5726782 DOI: 10.1103/physrevlett.119.188103] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Indexed: 06/07/2023]
Abstract
We study the statistical-mechanical properties of intertwined double-helical DNAs (DNA braids). In magnetic tweezers experiments, we find that torsionally stressed stretched braids supercoil via an abrupt buckling transition, which is associated with the nucleation of a braid end loop, and that the buckled braid is characterized by a proliferation of multiple domains. Differences between the mechanics of DNA braids and supercoiled single DNAs can be understood as an effect of the increased bulkiness in the structure of the former. The experimental results are in accord with the predictions of a statistical-mechanical model.
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18
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Ahmed W, Sala C, Hegde SR, Jha RK, Cole ST, Nagaraja V. Transcription facilitated genome-wide recruitment of topoisomerase I and DNA gyrase. PLoS Genet 2017; 13:e1006754. [PMID: 28463980 PMCID: PMC5433769 DOI: 10.1371/journal.pgen.1006754] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 05/16/2017] [Accepted: 04/10/2017] [Indexed: 01/28/2023] Open
Abstract
Movement of the transcription machinery along a template alters DNA topology resulting in the accumulation of supercoils in DNA. The positive supercoils generated ahead of transcribing RNA polymerase (RNAP) and the negative supercoils accumulating behind impose severe topological constraints impeding transcription process. Previous studies have implied the role of topoisomerases in the removal of torsional stress and the maintenance of template topology but the in vivo interaction of functionally distinct topoisomerases with heterogeneous chromosomal territories is not deciphered. Moreover, how the transcription-induced supercoils influence the genome-wide recruitment of DNA topoisomerases remains to be explored in bacteria. Using ChIP-Seq, we show the genome-wide occupancy profile of both topoisomerase I and DNA gyrase in conjunction with RNAP in Mycobacterium tuberculosis taking advantage of minimal topoisomerase representation in the organism. The study unveils the first in vivo genome-wide interaction of both the topoisomerases with the genomic regions and establishes that transcription-induced supercoils govern their recruitment at genomic sites. Distribution profiles revealed co-localization of RNAP and the two topoisomerases on the active transcriptional units (TUs). At a given locus, topoisomerase I and DNA gyrase were localized behind and ahead of RNAP, respectively, correlating with the twin-supercoiled domains generated. The recruitment of topoisomerases was higher at the genomic loci with higher transcriptional activity and/or at regions under high torsional stress compared to silent genomic loci. Importantly, the occupancy of DNA gyrase, sole type II topoisomerase in Mtb, near the Ter domain of the Mtb chromosome validates its function as a decatenase. The generation of DNA topological constraint is intrinsic to transcription. Although in vitro studies indicated DNA gyrase and topoisomerase I action in the removal of excess supercoils, ahead and behind the transcribing RNA polymerase, in vivo recruitment and interaction of both topoisomerases with the genome has not been investigated. Using advanced sequencing, we have mapped the genome-wide footprints of topoisomerase I and DNA gyrase along with RNAP in deadly pathogen, Mycobacterium tuberculosis. We show that in vivo distribution of topoisomerases is guided by active transcription and both the enzymes co-occupy active transcription units. We establish their interaction with the regions of genome having propensity to accumulate negative and positive supercoiled domains, validating their role in managing the twin supercoiled domains.
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Affiliation(s)
- Wareed Ahmed
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Claudia Sala
- Ecole Polytechnique Federale de Lausanne, Global Health Institute, Station 19, Lausanne, Switzerland
| | - Shubhada R. Hegde
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Rajiv Kumar Jha
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Stewart T. Cole
- Ecole Polytechnique Federale de Lausanne, Global Health Institute, Station 19, Lausanne, Switzerland
- * E-mail: (VN); (STC)
| | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
- Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
- * E-mail: (VN); (STC)
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19
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Brahmachari S, Marko JF. Torque and buckling in stretched intertwined double-helix DNAs. Phys Rev E 2017; 95:052401. [PMID: 28618488 DOI: 10.1103/physreve.95.052401] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Indexed: 01/11/2023]
Abstract
We present a statistical-mechanical model for the behavior of intertwined DNAs, with a focus on their torque and extension as a function of their catenation (linking) number and applied force, as studied in magnetic tweezers experiments. Our model produces results in good agreement with available experimental data and predicts a catenation-dependent effective twist modulus distinct from what is observed for twisted individual double-helix DNAs. We find that buckling occurs near the point where experiments have observed a kink in the extension versus linking number, and that the subsequent "supercoiled braid" state corresponds to a proliferation of multiple small plectoneme structures. We predict a discontinuity in extension at the buckling transition corresponding to nucleation of the first plectoneme domain. We also find that buckling occurs for lower linking number at lower salt; the opposite trend is observed for supercoiled single DNAs.
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Affiliation(s)
- Sumitabha Brahmachari
- Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA
| | - John F Marko
- Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA.,Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208, USA
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20
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Seol Y, Neuman KC. The dynamic interplay between DNA topoisomerases and DNA topology. Biophys Rev 2016; 8:101-111. [PMID: 28510219 DOI: 10.1007/s12551-016-0240-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 06/07/2016] [Indexed: 01/03/2023] Open
Abstract
Topological properties of DNA influence its structure and biochemical interactions. Within the cell, DNA topology is constantly in flux. Transcription and other essential processes, including DNA replication and repair, not only alter the topology of the genome but also introduce additional complications associated with DNA knotting and catenation. These topological perturbations are counteracted by the action of topoisomerases, a specialized class of highly conserved and essential enzymes that actively regulate the topological state of the genome. This dynamic interplay among DNA topology, DNA processing enzymes, and DNA topoisomerases is a pervasive factor that influences DNA metabolism in vivo. Building on the extensive structural and biochemical characterization over the past four decades that has established the fundamental mechanistic basis of topoisomerase activity, scientists have begun to explore the unique roles played by DNA topology in modulating and influencing the activity of topoisomerases. In this review we survey established and emerging DNA topology-dependent protein-DNA interactions with a focus on in vitro measurements of the dynamic interplay between DNA topology and topoisomerase activity.
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Affiliation(s)
- Yeonee Seol
- Laboratory of Single Molecule Biophysics, National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health, 50 South Dr., Room 3517, Bethesda, MD, 20892, USA
| | - Keir C Neuman
- Laboratory of Single Molecule Biophysics, National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health, 50 South Dr., Room 3517, Bethesda, MD, 20892, USA.
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21
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Chan HS, Liu Z. Thermodynamics and kinetics of TopoII action: A consensus on T-segment curvature selection? Comment on “Disentangling DNA Molecules” by Alexander Vologodskii. Phys Life Rev 2016; 18:135-138. [DOI: 10.1016/j.plrev.2016.05.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Accepted: 05/25/2016] [Indexed: 10/21/2022]
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22
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Roca J. In silico, in vitro and in vivo imageries of type II topoisomerases. Phys Life Rev 2016; 18:147-149. [DOI: 10.1016/j.plrev.2016.07.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 07/04/2016] [Indexed: 11/29/2022]
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23
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Abstract
Topological properties of DNA influence its structure and biochemical interactions. Within the cell DNA topology is constantly in flux. Transcription and other essential processes including DNA replication and repair, alter the topology of the genome, while introducing additional complications associated with DNA knotting and catenation. These topological perturbations are counteracted by the action of topoisomerases, a specialized class of highly conserved and essential enzymes that actively regulate the topological state of the genome. This dynamic interplay among DNA topology, DNA processing enzymes, and DNA topoisomerases, is a pervasive factor that influences DNA metabolism in vivo. Building on the extensive structural and biochemical characterization over the past four decades that established the fundamental mechanistic basis of topoisomerase activity, the unique roles played by DNA topology in modulating and influencing the activity of topoisomerases have begun to be explored. In this review we survey established and emerging DNA topology dependent protein-DNA interactions with a focus on in vitro measurements of the dynamic interplay between DNA topology and topoisomerase activity.
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Affiliation(s)
- Yeonee Seol
- Laboratory of Single Molecule Biophysics, NHLBI, National Institutes of Health, Bethesda, MD, 20892, U.S.A
| | - Keir C Neuman
- Laboratory of Single Molecule Biophysics, NHLBI, National Institutes of Health, Bethesda, MD, 20892, U.S.A
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24
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Vologodskii A. Disentangling DNA molecules. Phys Life Rev 2016; 18:118-134. [PMID: 27173054 DOI: 10.1016/j.plrev.2016.05.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Revised: 04/29/2016] [Accepted: 05/02/2016] [Indexed: 01/12/2023]
Abstract
The widespread circular form of DNA molecules inside cells creates very serious topological problems during replication. Due to the helical structure of the double helix the parental strands of circular DNA form a link of very high order, and yet they have to be unlinked before the cell division. DNA topoisomerases, the enzymes that catalyze passing of one DNA segment through another, solve this problem in principle. However, it is very difficult to remove all entanglements between the replicated DNA molecules due to huge length of DNA comparing to the cell size. One strategy that nature uses to overcome this problem is to create the topoisomerases that can dramatically reduce the fraction of linked circular DNA molecules relative to the corresponding fraction at thermodynamic equilibrium. This striking property of the enzymes means that the enzymes that interact with DNA only locally can access their topology, a global property of circular DNA molecules. This review considers the experimental studies of the phenomenon and analyzes the theoretical models that have been suggested in attempts to explain it. We describe here how various models of enzyme action can be investigated computationally. There is no doubt at the moment that we understand basic principles governing enzyme action. Still, there are essential quantitative discrepancies between the experimental data and the theoretical predictions. We consider how these discrepancies can be overcome.
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25
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Liu Z, Chan HS. Consistent rationalization of type-2 topoisomerases' unknotting, decatenating, supercoil-relaxing actions and their scaling relation. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:354103. [PMID: 26291958 DOI: 10.1088/0953-8984/27/35/354103] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
How type-2 topoisomerases discern global topology from local properties of DNA is not known precisely but the hypothesis that the enzymes selectively pass double-helix strands at hook-like juxtapositions is promising. Building upon an investigation of unknotting and decatenating using an improved wormlike DNA model, here we focus primarily on the enzymes' action in narrowing the distribution of linking number (Lk) in supercoiled DNA. Consistent with experiments, with selective passage at a hooked juxtaposition, the simulated narrowing factor RLk diminishes with decreasing DNA circle size but approaches an asymptotic RLk ≈ 1.7-1.8 for circle size ≳3.5 kb. For the larger DNA circles, we found that (RLk - 1) ≈ 0.42log10RK ≈ 0.68log10RL and thus RK ≈ (RL)(1.6) holds for the computed RLk and knot and catenane reduction factors RK and RL attained by selective passage at different juxtaposition geometries. Remarkably, this general scaling relation is essentially identical to that observed experimentally for several type-2 topoisomerases from a variety of organisms, indicating that the different disentangling powers of the topoisomerases likely arise from variations in the hooked geometries they select. Taken together, our results suggest strongly that type-2 topoisomerases recognize not only the curvature of the G-segment but also that of the T-segment.
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Affiliation(s)
- Zhirong Liu
- College of Chemistry and Molecular Engineering, Center for Quantitative Biology, and Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, People's Republic of China
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26
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Racko D, Benedetti F, Dorier J, Burnier Y, Stasiak A. Generation of supercoils in nicked and gapped DNA drives DNA unknotting and postreplicative decatenation. Nucleic Acids Res 2015; 43:7229-36. [PMID: 26150424 PMCID: PMC4551925 DOI: 10.1093/nar/gkv683] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 06/23/2015] [Indexed: 01/01/2023] Open
Abstract
Due to the helical structure of DNA the process of DNA replication is topologically complex. Freshly replicated DNA molecules are catenated with each other and are frequently knotted. For proper functioning of DNA it is necessary to remove all of these entanglements. This is done by DNA topoisomerases that pass DNA segments through each other. However, it has been a riddle how DNA topoisomerases select the sites of their action. In highly crowded DNA in living cells random passages between contacting segments would only increase the extent of entanglement. Using molecular dynamics simulations we observed that in actively supercoiled DNA molecules the entanglements resulting from DNA knotting or catenation spontaneously approach sites of nicks and gaps in the DNA. Type I topoisomerases, that preferentially act at sites of nick and gaps, are thus naturally provided with DNA–DNA juxtapositions where a passage results in an error-free DNA unknotting or DNA decatenation.
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Affiliation(s)
- Dusan Racko
- Center for Integrative Genomics, University of Lausanne, 1015-Lausanne, Switzerland SIB Swiss Institute of Bioinformatics, 1015-Lausanne, Switzerland Polymer Institute of the Slovak Academy of Sciences, 842 36 Bratislava, Slovakia
| | - Fabrizio Benedetti
- Center for Integrative Genomics, University of Lausanne, 1015-Lausanne, Switzerland SIB Swiss Institute of Bioinformatics, 1015-Lausanne, Switzerland
| | - Julien Dorier
- Center for Integrative Genomics, University of Lausanne, 1015-Lausanne, Switzerland Vital-IT, SIB Swiss Institute of Bioinformatics, 1015-Lausanne, Switzerland
| | - Yannis Burnier
- Center for Integrative Genomics, University of Lausanne, 1015-Lausanne, Switzerland Institute of Theoretical Physics, École Polytechnique Fédérale de Lausanne (EPFL), 1015-Lausanne, Switzerland
| | - Andrzej Stasiak
- Center for Integrative Genomics, University of Lausanne, 1015-Lausanne, Switzerland SIB Swiss Institute of Bioinformatics, 1015-Lausanne, Switzerland
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27
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Terekhova K, Marko JF, Mondragón A. Single-molecule analysis uncovers the difference between the kinetics of DNA decatenation by bacterial topoisomerases I and III. Nucleic Acids Res 2014; 42:11657-67. [PMID: 25232096 PMCID: PMC4191389 DOI: 10.1093/nar/gku785] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Escherichia coli topoisomerases I and III can decatenate double-stranded DNA (dsDNA) molecules containing single-stranded DNA regions or nicks as well as relax negatively supercoiled DNA. Although the proteins share a mechanism of action and have similar structures, they participate in different cellular processes. Whereas topoisomerase III is a more efficient decatenase than topoisomerase I, the opposite is true for DNA relaxation. In order to investigate the differences in the mechanism of these two prototypical type IA topoisomerases, we studied DNA decatenation at the single-molecule level using braids of intact dsDNA and nicked dsDNA with bulges. We found that neither protein decatenates an intact DNA braid. In contrast, both enzymes exhibited robust decatenation activity on DNA braids with a bulge. The experiments reveal that a main difference between the unbraiding mechanisms of these topoisomerases lies in the pauses between decatenation cycles. Shorter pauses for topoisomerase III result in a higher decatenation rate. In addition, topoisomerase III shows a strong dependence on the crossover angle of the DNA strands. These real-time observations reveal the kinetic characteristics of the decatenation mechanism and help explain the differences between their activities.
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Affiliation(s)
- Ksenia Terekhova
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - John F Marko
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208, USA
| | - Alfonso Mondragón
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
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28
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Thomson NH, Santos S, Mitchenall LA, Stuchinskaya T, Taylor JA, Maxwell A. DNA G-segment bending is not the sole determinant of topology simplification by type II DNA topoisomerases. Sci Rep 2014; 4:6158. [PMID: 25142513 PMCID: PMC4139952 DOI: 10.1038/srep06158] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 08/04/2014] [Indexed: 11/28/2022] Open
Abstract
DNA topoisomerases control the topology of DNA. Type II topoisomerases exhibit topology simplification, whereby products of their reactions are simplified beyond that expected based on thermodynamic equilibrium. The molecular basis for this process is unknown, although DNA bending has been implicated. To investigate the role of bending in topology simplification, the DNA bend angles of four enzymes of different types (IIA and IIB) were measured using atomic force microscopy (AFM). The enzymes tested were Escherichia coli topo IV and yeast topo II (type IIA enzymes that exhibit topology simplification), and Methanosarcina mazei topo VI and Sulfolobus shibatae topo VI (type IIB enzymes, which do not). Bend angles were measured using the manual tangent method from topographical AFM images taken with a novel amplitude-modulated imaging mode: small amplitude small set-point (SASS), which optimises resolution for a given AFM tip size and minimises tip convolution with the sample. This gave improved accuracy and reliability and revealed that all 4 topoisomerases bend DNA by a similar amount: ~120° between the DNA entering and exiting the enzyme complex. These data indicate that DNA bending alone is insufficient to explain topology simplification and that the ‘exit gate' may be an important determinant of this process.
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Affiliation(s)
- Neil H Thomson
- Department of Oral Biology, School of Dentistry and Molecular and Nanoscale Physics Group, School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Sergio Santos
- 1] Department of Oral Biology, School of Dentistry and Molecular and Nanoscale Physics Group, School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, United Kingdom [2]
| | - Lesley A Mitchenall
- Department of Biological Chemistry, John Innes Centre Norwich Research Park, Norwich NR4 7UH, United Kingdom
| | - Tanya Stuchinskaya
- 1] Department of Biological Chemistry, John Innes Centre Norwich Research Park, Norwich NR4 7UH, United Kingdom [2]
| | - James A Taylor
- 1] Department of Biological Chemistry, John Innes Centre Norwich Research Park, Norwich NR4 7UH, United Kingdom [2]
| | - Anthony Maxwell
- Department of Biological Chemistry, John Innes Centre Norwich Research Park, Norwich NR4 7UH, United Kingdom
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29
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Martínez-García B, Fernández X, Díaz-Ingelmo O, Rodríguez-Campos A, Manichanh C, Roca J. Topoisomerase II minimizes DNA entanglements by proofreading DNA topology after DNA strand passage. Nucleic Acids Res 2013; 42:1821-30. [PMID: 24185700 PMCID: PMC3919613 DOI: 10.1093/nar/gkt1037] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
By transporting one DNA double helix (T-segment) through a double-strand break in another (G-segment), topoisomerase II reduces fractions of DNA catenanes, knots and supercoils to below equilibrium values. How DNA segments are selected to simplify the equilibrium DNA topology is enigmatic, and the biological relevance of this activity is unclear. Here we examined the transit of the T-segment across the three gates of topoisomerase II (entry N-gate, DNA-gate and exit C-gate). Our experimental results uncovered that DNA transport probability is determined not only during the capture of a T-segment at the N-gate. When a captured T-segment has crossed the DNA-gate, it can backtrack to the N-gate instead of exiting by the C-gate. When such backtracking is precluded by locking the N-gate or by removing the C-gate, topoisomerase II no longer simplifies equilibrium DNA topology. Therefore, we conclude that the C-gate enables a post-DNA passage proofreading mechanism, which challenges the release of passed T-segments to either complete or cancel DNA transport. This proofreading activity not only clarifies how type-IIA topoisomerases simplify the equilibrium topology of DNA in free solution, but it may explain also why these enzymes are able to solve the topological constraints of intracellular DNA without randomly entangling adjacent chromosomal regions.
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Affiliation(s)
- Belén Martínez-García
- Instituto de Biología Molecular de Barcelona (IBMB), Consejo Superior de Investigaciones Científicas (CSIC), Barcelona 08028, Spain
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