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Göse M, Magill EE, Hughes-Games A, Shaw SJ, Diffin FM, Rawson T, Nagy Z, Seidel R, Szczelkun MD. Short-range translocation by a restriction enzyme motor triggers diffusion along DNA. Nat Chem Biol 2024; 20:689-698. [PMID: 38167920 PMCID: PMC11142916 DOI: 10.1038/s41589-023-01504-1] [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: 12/20/2022] [Accepted: 11/09/2023] [Indexed: 01/05/2024]
Abstract
Cleavage of bacteriophage DNA by the Type III restriction-modification enzymes requires long-range interaction between DNA sites. This is facilitated by one-dimensional diffusion ('DNA sliding') initiated by ATP hydrolysis catalyzed by a superfamily 2 helicase-like ATPase. Here we combined ultrafast twist measurements based on plasmonic DNA origami nano-rotors with stopped-flow fluorescence and gel-based assays to examine the role(s) of ATP hydrolysis. Our data show that the helicase-like domain has multiple roles. First, this domain stabilizes initial DNA interactions alongside the methyltransferase subunits. Second, it causes environmental changes in the flipped adenine base following hydrolysis of the first ATP. Finally, it remodels nucleoprotein interactions via constrained translocation of a ∼ 5 to 22-bp double stranded DNA loop. Initiation of DNA sliding requires 8-15 bp of DNA downstream of the motor, corresponding to the site of nuclease domain binding. Our data unify previous contradictory communication models for Type III enzymes.
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Affiliation(s)
- Martin Göse
- Peter Debye Institute for Soft Matter Physics, Universität Leipzig, Leipzig, Germany
| | - Emma E Magill
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol, UK
| | - Alex Hughes-Games
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol, UK
| | - Steven J Shaw
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol, UK
| | - Fiona M Diffin
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol, UK
| | - Tara Rawson
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol, UK
| | - Zsofia Nagy
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol, UK
| | - Ralf Seidel
- Peter Debye Institute for Soft Matter Physics, Universität Leipzig, Leipzig, Germany.
| | - Mark D Szczelkun
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol, UK.
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2
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Torres Montaguth OE, Cross SJ, Ingram KWA, Lee L, Diffin FM, Szczelkun MD. ENDO-Pore: high-throughput linked-end mapping of single DNA cleavage events using nanopore sequencing. Nucleic Acids Res 2021; 49:e118. [PMID: 34417616 PMCID: PMC8599736 DOI: 10.1093/nar/gkab727] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 08/05/2021] [Accepted: 08/12/2021] [Indexed: 12/26/2022] Open
Abstract
Mapping the precise position of DNA cleavage events plays a key role in determining the mechanism and function of endonucleases. ENDO-Pore is a high-throughput nanopore-based method that allows the time resolved mapping single molecule DNA cleavage events in vitro. Following linearisation of a circular DNA substrate by the endonuclease, a resistance cassette is ligated recording the position of the cleavage event. A library of single cleavage events is constructed and subjected to rolling circle amplification to generate concatemers. These are sequenced and used to produce accurate consensus sequences. To identify the cleavage site(s), we developed CSI (Cleavage Site Investigator). CSI recognizes the ends of the cassette ligated into the cleaved substrate and triangulates the position of the dsDNA break. We firstly benchmarked ENDO-Pore using Type II restriction endonucleases. Secondly, we analysed the effect of crRNA length on the cleavage pattern of CRISPR Cas12a. Finally, we mapped the time-resolved DNA cleavage by the Type ISP restriction endonuclease LlaGI that introduces random double-strand breaks into its DNA substrates.
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Affiliation(s)
- Oscar E Torres Montaguth
- DNA-Protein Interactions Unit, School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Stephen J Cross
- Wolfson Bioimaging Facility, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Kincaid W A Ingram
- DNA-Protein Interactions Unit, School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Laura Lee
- DNA-Protein Interactions Unit, School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Fiona M Diffin
- DNA-Protein Interactions Unit, School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Mark D Szczelkun
- DNA-Protein Interactions Unit, School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
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3
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Improving mobilization of foreign DNA into Zymomonas mobilis ZM4 by removal of multiple restriction systems. Appl Environ Microbiol 2021; 87:e0080821. [PMID: 34288704 PMCID: PMC8432527 DOI: 10.1128/aem.00808-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Zymomonas mobilis has emerged as a promising candidate for production of high-value bioproducts from plant biomass. However, a major limitation in equipping Z. mobilis with novel pathways to achieve this goal is restriction of heterologous DNA. Here, we characterized the contribution of several defense systems of Z. mobilis strain ZM4 to impeding heterologous gene transfer from an Escherichia coli donor. Bioinformatic analysis revealed that Z. mobilis ZM4 encodes a previously described mrr-like type IV restriction modification (RM) system, a type I-F CRISPR system, a chromosomal type I RM system (hsdMSc), and a previously uncharacterized type I RM system, located on an endogenous plasmid (hsdRMSp). The DNA recognition motif of HsdRMSp was identified by comparing the methylated DNA sequence pattern of mutants lacking one or both of the hsdMSc and hsdRMSp systems to that of the parent strain. The conjugation efficiency of synthetic plasmids containing single or combinations of the HsdMSc and HsdRMSp recognition sites indicated that both systems are active and decrease uptake of foreign DNA. In contrast, deletions of mrr and cas3 led to no detectable improvement in conjugation efficiency for the exogenous DNA tested. Thus, the suite of markerless restriction-negative strains that we constructed and the knowledge of this new restriction system and its DNA recognition motif provide the necessary platform to flexibly engineer the next generation of Z. mobilis strains for synthesis of valuable products. IMPORTANCEZymomonas mobilis is equipped with a number of traits that make it a desirable platform organism for metabolic engineering to produce valuable bioproducts. Engineering strains equipped with synthetic pathways for biosynthesis of new molecules requires integration of foreign genes. In this study, we developed an all-purpose strain, devoid of known host restriction systems and free of any antibiotic resistance markers, which dramatically improves the uptake efficiency of heterologous DNA into Z. mobilis ZM4. We also confirmed the role of a previously known restriction system as well as identifying a previously unknown type I RM system on an endogenous plasmid. Elimination of the barriers to DNA uptake as shown here will allow facile genetic engineering of Z. mobilis.
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4
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Structural and functional diversity among Type III restriction-modification systems that confer host DNA protection via methylation of the N4 atom of cytosine. PLoS One 2021; 16:e0253267. [PMID: 34228724 PMCID: PMC8259958 DOI: 10.1371/journal.pone.0253267] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 06/01/2021] [Indexed: 11/19/2022] Open
Abstract
We report a new subgroup of Type III Restriction-Modification systems that use m4C methylation for host protection. Recognition specificities for six such systems, each recognizing a novel motif, have been determined using single molecule real-time DNA sequencing. In contrast to all previously characterized Type III systems which modify adenine to m6A, protective methylation of the host genome in these new systems is achieved by the N4-methylation of a cytosine base in one strand of an asymmetric 4 to 6 base pair recognition motif. Type III systems are heterotrimeric enzyme complexes containing a single copy of an ATP-dependent restriction endonuclease-helicase (Res) and a dimeric DNA methyltransferase (Mod). The Type III Mods are beta-class amino-methyltransferases, examples of which form either N6-methyl adenine or N4-methyl cytosine in Type II RM systems. The Type III m4C Mod and Res proteins are diverged, suggesting ancient origin or that m4C modification has arisen from m6A MTases multiple times in diverged lineages. Two of the systems, from thermophilic organisms, required expression of both Mod and Res to efficiently methylate an E. coli host, unlike previous findings that Mod alone is proficient at modification, suggesting that the division of labor between protective methylation and restriction activities is atypical in these systems. Two of the characterized systems, and many homologous putative systems, appear to include a third protein; a conserved putative helicase/ATPase subunit of unknown function and located 5’ of the mod gene. The function of this additional ATPase is not yet known, but close homologs co-localize with the typical Mod and Res genes in hundreds of putative Type III systems. Our findings demonstrate a rich diversity within Type III RM systems.
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5
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Isaev AB, Musharova OS, Severinov KV. Microbial Arsenal of Antiviral Defenses - Part I. BIOCHEMISTRY (MOSCOW) 2021; 86:319-337. [PMID: 33838632 DOI: 10.1134/s0006297921030081] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Bacteriophages or phages are viruses that infect bacterial cells (for the scope of this review we will also consider viruses that infect Archaea). Constant threat of phage infection is a major force that shapes evolution of the microbial genomes. To withstand infection, bacteria had evolved numerous strategies to avoid recognition by phages or to directly interfere with phage propagation inside the cell. Classical molecular biology and genetic engineering have been deeply intertwined with the study of phages and host defenses. Nowadays, owing to the rise of phage therapy, broad application of CRISPR-Cas technologies, and development of bioinformatics approaches that facilitate discovery of new systems, phage biology experiences a revival. This review describes variety of strategies employed by microbes to counter phage infection, with a focus on novel systems discovered in recent years. First chapter covers defense associated with cell surface, role of small molecules, and innate immunity systems relying on DNA modification.
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Affiliation(s)
- Artem B Isaev
- Skolkovo Institute of Science and Technology, Moscow, 143028, Russia.
| | - Olga S Musharova
- Skolkovo Institute of Science and Technology, Moscow, 143028, Russia. .,Institute of Molecular Genetics, Moscow, 119334, Russia
| | - Konstantin V Severinov
- Skolkovo Institute of Science and Technology, Moscow, 143028, Russia. .,Waksman Institute of Microbiology, Piscataway, NJ 08854, USA
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6
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Abstract
Restriction enzymes provided the foundation on which molecular cloning was built, and they remain as essential tools in current recombinant DNA technology. The three classes of restriction enzymes and their features are introduced here.
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7
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Tumuluri VS, Rajgor V, Xu SY, Chouhan OP, Saikrishnan K. Mechanism of DNA cleavage by the endonuclease SauUSI: a major barrier to horizontal gene transfer and antibiotic resistance in Staphylococcus aureus. Nucleic Acids Res 2021; 49:2161-2178. [PMID: 33533920 PMCID: PMC7913695 DOI: 10.1093/nar/gkab042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 01/11/2021] [Accepted: 01/31/2021] [Indexed: 02/06/2023] Open
Abstract
Acquisition of foreign DNA by Staphylococcus aureus, including vancomycin resistance genes, is thwarted by the ATP-dependent endonuclease SauUSI. Deciphering the mechanism of action of SauUSI could unravel the reason how it singularly plays a major role in preventing horizontal gene transfer (HGT) in S. aureus. Here, we report a detailed biochemical and structural characterization of SauUSI, which reveals that in the presence of ATP, the enzyme can cleave DNA having a single or multiple target site/s. Remarkably, in the case of multiple target sites, the entire region of DNA flanked by two target sites is shred into smaller fragments by SauUSI. Crystal structure of SauUSI reveals a stable dimer held together by the nuclease domains, which are spatially arranged to hydrolyze the phosphodiester bonds of both strands of the duplex. Thus, the architecture of the dimeric SauUSI facilitates cleavage of either single-site or multi-site DNA. The structure also provides insights into the molecular basis of target recognition by SauUSI. We show that target recognition activates ATP hydrolysis by the helicase-like ATPase domain, which powers active directional movement (translocation) of SauUSI along the DNA. We propose that a pile-up of multiple translocating SauUSI molecules against a stationary SauUSI bound to a target site catalyzes random double-stranded breaks causing shredding of the DNA between two target sites. The extensive and irreparable damage of the foreign DNA by shredding makes SauUSI a potent barrier against HGT.
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Affiliation(s)
| | - Vrunda Rajgor
- Department of Biology, Indian Institute of Science Education and Research, Pune 411008, India
| | - Shuang-Yong Xu
- New England Biolabs Inc., Research Department, Ipswich, MA 01938, USA
| | - Om Prakash Chouhan
- Department of Biology, Indian Institute of Science Education and Research, Pune 411008, India
| | - Kayarat Saikrishnan
- Department of Biology, Indian Institute of Science Education and Research, Pune 411008, India
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8
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Gordeeva J, Morozova N, Sierro N, Isaev A, Sinkunas T, Tsvetkova K, Matlashov M, Truncaite L, Morgan RD, Ivanov NV, Siksnys V, Zeng L, Severinov K. BREX system of Escherichia coli distinguishes self from non-self by methylation of a specific DNA site. Nucleic Acids Res 2019; 47:253-265. [PMID: 30418590 PMCID: PMC6326788 DOI: 10.1093/nar/gky1125] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 10/24/2018] [Indexed: 01/09/2023] Open
Abstract
Prokaryotes evolved numerous systems that defend against predation by bacteriophages. In addition to well-known restriction-modification and CRISPR-Cas immunity systems, many poorly characterized systems exist. One class of such systems, named BREX, consists of a putative phosphatase, a methyltransferase and four other proteins. A Bacillus cereus BREX system provides resistance to several unrelated phages and leads to modification of specific motif in host DNA. Here, we study the action of BREX system from a natural Escherichia coli isolate. We show that while it makes cells resistant to phage λ infection, induction of λ prophage from cells carrying BREX leads to production of viruses that overcome the defense. The induced phage DNA contains a methylated adenine residue in a specific motif. The same modification is found in the genome of BREX-carrying cells. The results establish, for the first time, that immunity to BREX system defense is provided by an epigenetic modification.
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Affiliation(s)
- Julia Gordeeva
- Skolkovo Institute of Science and Technology, Moscow 143028, Russia
| | - Natalya Morozova
- Skolkovo Institute of Science and Technology, Moscow 143028, Russia.,Peter the Great St Petersburg State Polytechnic University, St Petersburg 195251, Russia
| | - Nicolas Sierro
- Philip Morris International R&D, Philip Morris Products S.A., Neuchâtel 2000, Switzerland
| | - Artem Isaev
- Skolkovo Institute of Science and Technology, Moscow 143028, Russia
| | - Tomas Sinkunas
- Institute of Biotechnology, Vilnius University, Sauletekio Avenue 7, Vilnius 10257, Lithuania
| | - Ksenia Tsvetkova
- Skolkovo Institute of Science and Technology, Moscow 143028, Russia
| | | | - Lidija Truncaite
- Institute of Biochemistry, Vilnius University, Sauletekio Avenue 7, Vilnius 10257, Lithuania
| | | | - Nikolai V Ivanov
- Philip Morris International R&D, Philip Morris Products S.A., Neuchâtel 2000, Switzerland
| | - Virgis Siksnys
- Institute of Biotechnology, Vilnius University, Sauletekio Avenue 7, Vilnius 10257, Lithuania
| | - Lanying Zeng
- Department of Biochemistry and Biophysics, Center for Phage Technology, Texas A&M University, College Station, TX 77843, USA
| | - Konstantin Severinov
- Skolkovo Institute of Science and Technology, Moscow 143028, Russia.,Peter the Great St Petersburg State Polytechnic University, St Petersburg 195251, Russia.,Waksman Institute of Microbiology, Piscataway, NJ 08854, USA
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9
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Toliusis P, Zaremba M, Silanskas A, Szczelkun MD, Siksnys V. CgII cleaves DNA using a mechanism distinct from other ATP-dependent restriction endonucleases. Nucleic Acids Res 2017; 45:8435-8447. [PMID: 28854738 PMCID: PMC5737866 DOI: 10.1093/nar/gkx580] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 06/28/2017] [Indexed: 01/10/2023] Open
Abstract
The restriction endonuclease CglI from Corynebacterium glutamicum recognizes an asymmetric 5′-GCCGC-3′ site and cleaves the DNA 7 and 6/7 nucleotides downstream on the top and bottom DNA strands, respectively, in an NTP-hydrolysis dependent reaction. CglI is composed of two different proteins: an endonuclease (R.CglI) and a DEAD-family helicase-like ATPase (H.CglI). These subunits form a heterotetrameric complex with R2H2 stoichiometry. However, the R2H2·CglI complex has only one nuclease active site sufficient to cut one DNA strand suggesting that two complexes are required to introduce a double strand break. Here, we report studies to evaluate the DNA cleavage mechanism of CglI. Using one- and two-site circular DNA substrates we show that CglI does not require two sites on the same DNA for optimal catalytic activity. However, one-site linear DNA is a poor substrate, supporting a mechanism where CglI complexes must communicate along the one-dimensional DNA contour before cleavage is activated. Based on experimental data, we propose that adenosine triphosphate (ATP) hydrolysis by CglI produces translocation on DNA preferentially in a downstream direction from the target, although upstream translocation is also possible. Our results are consistent with a mechanism of CglI action that is distinct from that of other ATP-dependent restriction-modification enzymes.
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Affiliation(s)
- Paulius Toliusis
- Department of Protein-DNA Interactions, Institute of Biotechnology, Vilnius University, Sauletekio al. 7, LT-10257, Vilnius, Lithuania
| | - Mindaugas Zaremba
- Department of Protein-DNA Interactions, Institute of Biotechnology, Vilnius University, Sauletekio al. 7, LT-10257, Vilnius, Lithuania
| | - Arunas Silanskas
- Department of Protein-DNA Interactions, Institute of Biotechnology, Vilnius University, Sauletekio al. 7, LT-10257, Vilnius, Lithuania
| | - Mark D Szczelkun
- DNA-Protein Interactions Unit, School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Virginijus Siksnys
- Department of Protein-DNA Interactions, Institute of Biotechnology, Vilnius University, Sauletekio al. 7, LT-10257, Vilnius, Lithuania
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10
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Kostiuk G, Dikic J, Schwarz FW, Sasnauskas G, Seidel R, Siksnys V. The dynamics of the monomeric restriction endonuclease BcnI during its interaction with DNA. Nucleic Acids Res 2017; 45:5968-5979. [PMID: 28453854 PMCID: PMC5449598 DOI: 10.1093/nar/gkx294] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 04/13/2017] [Indexed: 11/24/2022] Open
Abstract
Endonucleases that generate DNA double strand breaks often employ two independent subunits such that the active site from each subunit cuts either DNA strand. Restriction enzyme BcnI is a remarkable exception. It binds to the 5΄-CC/SGG-3΄ (where S = C or G, ‘/’ designates the cleavage position) target as a monomer forming an asymmetric complex, where a single catalytic center approaches the scissile phosphodiester bond in one of DNA strands. Bulk kinetic measurements have previously shown that the same BcnI molecule cuts both DNA strands at the target site without dissociation from the DNA. Here, we analyse the BcnI DNA binding and target recognition steps at the single molecule level. We find, using FRET, that BcnI adopts either ‘open’ or ‘closed’ conformation in solution. Next, we directly demonstrate that BcnI slides over long distances on DNA using 1D diffusion and show that sliding is accompanied by occasional jumping events, where the enzyme leaves the DNA and rebinds immediately at a distant site. Furthermore, we quantify the dynamics of the BcnI interactions with cognate and non-cognate DNA, and determine the preferred binding orientation of BcnI to the target site. These results provide new insights into the intricate dynamics of BcnI–DNA interactions.
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Affiliation(s)
- Georgij Kostiuk
- Institute of Biotechnology, Vilnius University, Sauletekio av. 7, LT-10257 Vilnius, Lithuania
| | - Jasmina Dikic
- Molecular Biophysics group, Institute for Experimental Physics I, Universität Leipzig, Linnéstr. 5, 04103 Leipzig, Germany
| | - Friedrich W Schwarz
- BCUBE, Technische Universitaet Dresden, Arnoldstrasse 18, 01307 Dresden, Germany
| | - Giedrius Sasnauskas
- Institute of Biotechnology, Vilnius University, Sauletekio av. 7, LT-10257 Vilnius, Lithuania
| | - Ralf Seidel
- Molecular Biophysics group, Institute for Experimental Physics I, Universität Leipzig, Linnéstr. 5, 04103 Leipzig, Germany
| | - Virginijus Siksnys
- Institute of Biotechnology, Vilnius University, Sauletekio av. 7, LT-10257 Vilnius, Lithuania
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11
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Single molecule high-throughput footprinting of small and large DNA ligands. Nat Commun 2017; 8:304. [PMID: 28824174 PMCID: PMC5563512 DOI: 10.1038/s41467-017-00379-w] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Accepted: 06/20/2017] [Indexed: 02/04/2023] Open
Abstract
Most DNA processes are governed by molecular interactions that take place in a sequence-specific manner. Determining the sequence selectivity of DNA ligands is still a challenge, particularly for small drugs where labeling or sequencing methods do not perform well. Here, we present a fast and accurate method based on parallelized single molecule magnetic tweezers to detect the sequence selectivity and characterize the thermodynamics and kinetics of binding in a single assay. Mechanical manipulation of DNA hairpins with an engineered sequence is used to detect ligand binding as blocking events during DNA unzipping, allowing determination of ligand selectivity both for small drugs and large proteins with nearly base-pair resolution in an unbiased fashion. The assay allows investigation of subtle details such as the effect of flanking sequences or binding cooperativity. Unzipping assays on hairpin substrates with an optimized flat free energy landscape containing all binding motifs allows determination of the ligand mechanical footprint, recognition site, and binding orientation. Mapping the sequence specificity of DNA ligands remains a challenge, particularly for small drugs. Here the authors develop a parallelized single molecule magnetic tweezers approach using engineered DNA hairpins that can detect sequence selectivity, thermodynamics and kinetics of binding for small drugs and large proteins.
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12
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Rutkauskas M, Krivoy A, Szczelkun MD, Rouillon C, Seidel R. Single-Molecule Insight Into Target Recognition by CRISPR-Cas Complexes. Methods Enzymol 2016; 582:239-273. [PMID: 28062037 DOI: 10.1016/bs.mie.2016.10.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Ribonucleoprotein (RNP) complexes from CRISPR-Cas systems have attracted enormous interest since they can be easily and flexibly reprogrammed to target any desired locus for genome engineering and gene regulation applications. Basis for the programmability is a short RNA (crRNA) inside these complexes that recognizes the target nucleic acid by base pairing. For CRISPR-Cas systems that target double-stranded DNA this results in local DNA unwinding and formation of a so-called R-loop structure. Here we provide an overview how this target recognition mechanism can be dissected in great detail at the level of a single molecule. Specifically, we demonstrate how magnetic tweezers are applied to measure the local DNA unwinding at the target in real time. To this end we introduce the technique and the measurement principle. By studying modifications of the consensus target sequence, we show how different sequence elements contribute to the target recognition mechanism. From these data, a unified target recognition mechanism can be concluded for the RNPs Cascade and Cas9 from types I and II CRISPR-Cas systems. R-loop formation is hereby initiated on the target at an upstream element, called protospacer adjacent motif (PAM), from which the R-loop structure zips directionally toward the PAM-distal end of the target. At mismatch positions, the R-loop propagation stalls and further propagation competes with collapse of the structure. Upon full R-loop zipping conformational changes within the RNPs trigger degradation of the DNA target. This represents a shared labor mechanism in which zipping between nucleic acid strands is the actual target recognition mechanism while sensing of the R-loop arrival at the PAM-distal end just verifies the success of the full zipping.
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Affiliation(s)
- M Rutkauskas
- Molecular Biophysics Group, Institute for Experimental Physics I, Universität Leipzig, Leipzig, Germany
| | - A Krivoy
- Molecular Biophysics Group, Institute for Experimental Physics I, Universität Leipzig, Leipzig, Germany; Skolkovo Institute of Science and Technology, Skolkovo, Russia
| | - M D Szczelkun
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - C Rouillon
- Molecular Biophysics Group, Institute for Experimental Physics I, Universität Leipzig, Leipzig, Germany.
| | - R Seidel
- Molecular Biophysics Group, Institute for Experimental Physics I, Universität Leipzig, Leipzig, Germany.
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13
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Daldrop P, Brutzer H, Huhle A, Kauert DJ, Seidel R. Extending the range for force calibration in magnetic tweezers. Biophys J 2016; 108:2550-2561. [PMID: 25992733 DOI: 10.1016/j.bpj.2015.04.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 04/10/2015] [Accepted: 04/14/2015] [Indexed: 12/11/2022] Open
Abstract
Magnetic tweezers are a wide-spread tool used to study the mechanics and the function of a large variety of biomolecules and biomolecular machines. This tool uses a magnetic particle and a strong magnetic field gradient to apply defined forces to the molecule of interest. Forces are typically quantified by analyzing the lateral fluctuations of the biomolecule-tethered particle in the direction perpendicular to the applied force. Since the magnetic field pins the anisotropy axis of the particle, the lateral fluctuations follow the geometry of a pendulum with a short pendulum length along and a long pendulum length perpendicular to the field lines. Typically, the short pendulum geometry is used for force calibration by power-spectral-density (PSD) analysis, because the movement of the bead in this direction can be approximated by a simple translational motion. Here, we provide a detailed analysis of the fluctuations according to the long pendulum geometry and show that for this direction, both the translational and the rotational motions of the particle have to be considered. We provide analytical formulas for the PSD of this coupled system that agree well with PSDs obtained in experiments and simulations and that finally allow a faithful quantification of the magnetic force for the long pendulum geometry. We furthermore demonstrate that this methodology allows the calibration of much larger forces than the short pendulum geometry in a tether-length-dependent manner. In addition, the accuracy of determination of the absolute force is improved. Our force calibration based on the long pendulum geometry will facilitate high-resolution magnetic-tweezers experiments that rely on short molecules and large forces, as well as highly parallelized measurements that use low frame rates.
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Affiliation(s)
- Peter Daldrop
- Institute for Molecular Cell Biology, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Hergen Brutzer
- Biotechnology Center, Technische Universität Dresden, Dresden, Germany
| | - Alexander Huhle
- Biotechnology Center, Technische Universität Dresden, Dresden, Germany
| | - Dominik J Kauert
- Institute for Molecular Cell Biology, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Ralf Seidel
- Institute for Molecular Cell Biology, Westfälische Wilhelms-Universität Münster, Münster, Germany; Biotechnology Center, Technische Universität Dresden, Dresden, Germany; Institute for Experimental Physics I, Universität Leipzig, Leipzig, Germany.
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14
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Tóth J, Bollins J, Szczelkun MD. Re-evaluating the kinetics of ATP hydrolysis during initiation of DNA sliding by Type III restriction enzymes. Nucleic Acids Res 2015; 43:10870-81. [PMID: 26538601 PMCID: PMC4678819 DOI: 10.1093/nar/gkv1154] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 10/19/2015] [Indexed: 01/05/2023] Open
Abstract
DNA cleavage by the Type III restriction enzymes requires long-range protein communication between recognition sites facilitated by thermally-driven 1D diffusion. This 'DNA sliding' is initiated by hydrolysis of multiple ATPs catalysed by a helicase-like domain. Two distinct ATPase phases were observed using short oligoduplex substrates; the rapid consumption of ∼10 ATPs coupled to a protein conformation switch followed by a slower phase, the duration of which was dictated by the rate of dissociation from the recognition site. Here, we show that the second ATPase phase is both variable and only observable when DNA ends are proximal to the recognition site. On DNA with sites more distant from the ends, a single ATPase phase coupled to the conformation switch was observed and subsequent site dissociation required little or no further ATP hydrolysis. The overall DNA dissociation kinetics (encompassing site release, DNA sliding and escape via a DNA end) were not influenced by the second phase. Although the data simplifies the ATP hydrolysis scheme for Type III restriction enzymes, questions remain as to why multiple ATPs are hydrolysed to prepare for DNA sliding.
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Affiliation(s)
- Júlia Tóth
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - Jack Bollins
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - Mark D Szczelkun
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
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15
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Gupta YK, Chan SH, Xu SY, Aggarwal AK. Structural basis of asymmetric DNA methylation and ATP-triggered long-range diffusion by EcoP15I. Nat Commun 2015; 6:7363. [PMID: 26067164 PMCID: PMC4490356 DOI: 10.1038/ncomms8363] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Accepted: 04/30/2015] [Indexed: 11/09/2022] Open
Abstract
Type III R–M enzymes were identified >40 years ago and yet there is no structural information on these multisubunit enzymes. Here we report the structure of a Type III R–M system, consisting of the entire EcoP15I complex (Mod2Res1) bound to DNA. The structure suggests how ATP hydrolysis is coupled to long-range diffusion of a helicase on DNA, and how a dimeric methyltransferase functions to methylate only one of the two DNA strands. We show that the EcoP15I motor domains are specifically adapted to bind double-stranded DNA and to facilitate DNA sliding via a novel ‘Pin' domain. We also uncover unexpected ‘division of labour', where one Mod subunit recognizes DNA, while the other Mod subunit methylates the target adenine—a mechanism that may extend to adenine N6 RNA methylation in mammalian cells. Together the structure sheds new light on the mechanisms of both helicases and methyltransferases in DNA and RNA metabolism. Type III restriction–modification enzymes consists of two methylation and one or two restriction subunits. Here the authors report the structure of the full EcoP15I complex bound to DNA, which suggests mechanisms for ATP hydrolysis dependent diffusion along DNA and how a dimeric methyltransferase modifies only one DNA strand.
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Affiliation(s)
- Yogesh K Gupta
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, Box 1677, 1425 Madison Avenue, New York, New York 10029, USA
| | - Siu-Hong Chan
- New England Biolabs Inc., 240 County Road, Ipswich, Massachusetts 01938, USA
| | - Shuang-Yong Xu
- New England Biolabs Inc., 240 County Road, Ipswich, Massachusetts 01938, USA
| | - Aneel K Aggarwal
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, Box 1677, 1425 Madison Avenue, New York, New York 10029, USA
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16
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Zaremba M, Toliusis P, Grigaitis R, Manakova E, Silanskas A, Tamulaitiene G, Szczelkun MD, Siksnys V. DNA cleavage by CgII and NgoAVII requires interaction between N- and R-proteins and extensive nucleotide hydrolysis. Nucleic Acids Res 2014; 42:13887-96. [PMID: 25429977 PMCID: PMC4267653 DOI: 10.1093/nar/gku1236] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 10/31/2014] [Accepted: 11/10/2014] [Indexed: 01/07/2023] Open
Abstract
The stress-sensitive restriction-modification (RM) system CglI from Corynebacterium glutamicum and the homologous NgoAVII RM system from Neisseria gonorrhoeae FA1090 are composed of three genes: a DNA methyltransferase (M.CglI and M.NgoAVII), a putative restriction endonuclease (R.CglI and R.NgoAVII, or R-proteins) and a predicted DEAD-family helicase/ATPase (N.CglI and N.NgoAVII or N-proteins). Here we report a biochemical characterization of the R- and N-proteins. Size-exclusion chromatography and SAXS experiments reveal that the isolated R.CglI, R.NgoAVII and N.CglI proteins form homodimers, while N.NgoAVII is a monomer in solution. Moreover, the R.CglI and N.CglI proteins assemble in a complex with R2N2 stoichiometry. Next, we show that N-proteins have ATPase activity that is dependent on double-stranded DNA and is stimulated by the R-proteins. Functional ATPase activity and extensive ATP hydrolysis (∼170 ATP/s/monomer) are required for site-specific DNA cleavage by R-proteins. We show that ATP-dependent DNA cleavage by R-proteins occurs at fixed positions (6-7 nucleotides) downstream of the asymmetric recognition sequence 5'-GCCGC-3'. Despite similarities to both Type I and II restriction endonucleases, the CglI and NgoAVII enzymes may employ a unique catalytic mechanism for DNA cleavage.
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Affiliation(s)
- Mindaugas Zaremba
- Department of Protein-DNA Interactions, Institute of Biotechnology, Vilnius University, Graiciuno 8, LT-02241 Vilnius, Lithuania
| | - Paulius Toliusis
- Department of Protein-DNA Interactions, Institute of Biotechnology, Vilnius University, Graiciuno 8, LT-02241 Vilnius, Lithuania
| | - Rokas Grigaitis
- Department of Protein-DNA Interactions, Institute of Biotechnology, Vilnius University, Graiciuno 8, LT-02241 Vilnius, Lithuania
| | - Elena Manakova
- Department of Protein-DNA Interactions, Institute of Biotechnology, Vilnius University, Graiciuno 8, LT-02241 Vilnius, Lithuania
| | - Arunas Silanskas
- Department of Protein-DNA Interactions, Institute of Biotechnology, Vilnius University, Graiciuno 8, LT-02241 Vilnius, Lithuania
| | - Giedre Tamulaitiene
- Department of Protein-DNA Interactions, Institute of Biotechnology, Vilnius University, Graiciuno 8, LT-02241 Vilnius, Lithuania
| | - Mark D Szczelkun
- DNA-Protein Interactions Unit, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Virginijus Siksnys
- Department of Protein-DNA Interactions, Institute of Biotechnology, Vilnius University, Graiciuno 8, LT-02241 Vilnius, Lithuania
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17
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Simons M, Diffin FM, Szczelkun MD. ClpXP protease targets long-lived DNA translocation states of a helicase-like motor to cause restriction alleviation. Nucleic Acids Res 2014; 42:12082-91. [PMID: 25260590 PMCID: PMC4231737 DOI: 10.1093/nar/gku851] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
We investigated how Escherichia coli ClpXP targets the helicase-nuclease (HsdR) subunit of the bacterial Type I restriction–modification enzyme EcoKI during restriction alleviation (RA). RA is a temporary reduction in endonuclease activity that occurs when Type I enzymes bind unmodified recognition sites on the host genome. These conditions arise upon acquisition of a new system by a naïve host, upon generation of new sites by genome rearrangement/mutation or during homologous recombination between hemimethylated DNA. Using recombinant DNA and proteins in vitro, we demonstrate that ClpXP targets EcoKI HsdR during dsDNA translocation on circular DNA but not on linear DNA. Protein roadblocks did not activate HsdR proteolysis. We suggest that DNA translocation lifetime, which is elevated on circular DNA relative to linear DNA, is important to RA. To identify the ClpX degradation tag (degron) in HsdR, we used bioinformatics and biochemical assays to design N- and C-terminal mutations that were analysed in vitro and in vivo. None of the mutants produced a phenotype consistent with loss of the degron, suggesting an as-yet-unidentified recognition pathway. We note that an EcoKI nuclease mutant still produces cell death in a clpx− strain, consistent with DNA damage induced by unregulated motor activity.
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Affiliation(s)
- Michelle Simons
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol, BS8 1TD, UK
| | - Fiona M Diffin
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol, BS8 1TD, UK
| | - Mark D Szczelkun
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol, BS8 1TD, UK
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18
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Ma L, Wu X. WITHDRAWN: Type III restriction-modification enzyme EcoP15I's base flipping mechanism and its mismatch cleavage on two head-to-head oriented recognition sites. Biochem Biophys Res Commun 2014:S0006-291X(14)00373-8. [PMID: 24589737 DOI: 10.1016/j.bbrc.2014.02.102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 02/21/2014] [Indexed: 10/25/2022]
Abstract
This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.
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Affiliation(s)
- Long Ma
- Biomolecular Sciences Research Complex, EaStCHEM School of Chemistry, University of St Andrews, Fife KY16 9ST, UK.
| | - Xiaohua Wu
- EaStChem School of Chemistry, University of Edinburgh, The King's Buildings, Edinburgh, EH9 3JJ, UK
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19
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Butterer A, Pernstich C, Smith RM, Sobott F, Szczelkun MD, Tóth J. Type III restriction endonucleases are heterotrimeric: comprising one helicase-nuclease subunit and a dimeric methyltransferase that binds only one specific DNA. Nucleic Acids Res 2014; 42:5139-50. [PMID: 24510100 PMCID: PMC4005696 DOI: 10.1093/nar/gku122] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Fundamental aspects of the biochemistry of Type III restriction endonucleases remain unresolved despite being characterized by numerous research groups in the past decades. One such feature is the subunit stoichiometry of these hetero-oligomeric enzyme complexes, which has important implications for the reaction mechanism. In this study, we present a series of results obtained by native mass spectrometry and size exclusion chromatography with multi-angle light scattering consistent with a 1:2 ratio of Res to Mod subunits in the EcoP15I, EcoPI and PstII complexes as the main holoenzyme species and a 1:1 stoichiometry of specific DNA (sDNA) binding by EcoP15I and EcoPI. Our data are also consistent with a model where ATP hydrolysis activated by recognition site binding leads to release of the enzyme from the site, dissociation from the substrate via a free DNA end and cleavage of the DNA. These results are discussed critically in the light of the published literature, aiming to resolve controversies and discuss consequences in terms of the reaction mechanism.
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Affiliation(s)
- Annika Butterer
- Biomolecular & Analytical Mass Spectrometry and Center for Proteomics (CFP-CeProMa), Department of Chemistry, University of Antwerp, Antwerp 2020, Belgium and DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
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20
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Rao DN, Dryden DTF, Bheemanaik S. Type III restriction-modification enzymes: a historical perspective. Nucleic Acids Res 2014; 42:45-55. [PMID: 23863841 PMCID: PMC3874151 DOI: 10.1093/nar/gkt616] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 05/28/2013] [Accepted: 06/24/2013] [Indexed: 11/12/2022] Open
Abstract
Restriction endonucleases interact with DNA at specific sites leading to cleavage of DNA. Bacterial DNA is protected from restriction endonuclease cleavage by modifying the DNA using a DNA methyltransferase. Based on their molecular structure, sequence recognition, cleavage position and cofactor requirements, restriction-modification (R-M) systems are classified into four groups. Type III R-M enzymes need to interact with two separate unmethylated DNA sequences in inversely repeated head-to-head orientations for efficient cleavage to occur at a defined location (25-27 bp downstream of one of the recognition sites). Like the Type I R-M enzymes, Type III R-M enzymes possess a sequence-specific ATPase activity for DNA cleavage. ATP hydrolysis is required for the long-distance communication between the sites before cleavage. Different models, based on 1D diffusion and/or 3D-DNA looping, exist to explain how the long-distance interaction between the two recognition sites takes place. Type III R-M systems are found in most sequenced bacteria. Genome sequencing of many pathogenic bacteria also shows the presence of a number of phase-variable Type III R-M systems, which play a role in virulence. A growing number of these enzymes are being subjected to biochemical and genetic studies, which, when combined with ongoing structural analyses, promise to provide details for mechanisms of DNA recognition and catalysis.
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Affiliation(s)
- Desirazu N. Rao
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India and School of Chemistry, The King’s Buildings, The University of Edinburgh, Edinburgh EH9 3JJ, Scotland, UK
| | - David T. F. Dryden
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India and School of Chemistry, The King’s Buildings, The University of Edinburgh, Edinburgh EH9 3JJ, Scotland, UK
| | - Shivakumara Bheemanaik
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India and School of Chemistry, The King’s Buildings, The University of Edinburgh, Edinburgh EH9 3JJ, Scotland, UK
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21
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Schwarz FW, Tóth J, van Aelst K, Cui G, Clausing S, Szczelkun MD, Seidel R. The helicase-like domains of type III restriction enzymes trigger long-range diffusion along DNA. Science 2013; 340:353-6. [PMID: 23599494 PMCID: PMC3646237 DOI: 10.1126/science.1231122] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Helicases are ubiquitous adenosine triphosphatases (ATPases) with widespread roles in genome metabolism. Here, we report a previously undescribed functionality for ATPases with helicase-like domains; namely, that ATP hydrolysis can trigger ATP-independent long-range protein diffusion on DNA in one dimension (1D). Specifically, using single-molecule fluorescence microscopy we show that the Type III restriction enzyme EcoP15I uses its ATPase to switch into a distinct structural state that diffuses on DNA over long distances and long times. The switching occurs only upon binding to the target site and requires hydrolysis of ~30 ATPs. We define the mechanism for these enzymes and show how ATPase activity is involved in DNA target site verification and 1D signaling, roles that are common in DNA metabolism: for example, in nucleotide excision and mismatch repair.
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Affiliation(s)
- Friedrich W. Schwarz
- DNA motors group, Biotechnology Center, Technische Universität Dresden, 01062 Dresden, Germany
| | - Júlia Tóth
- DNA-Protein Interactions Unit, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Kara van Aelst
- DNA-Protein Interactions Unit, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Guanshen Cui
- DNA-Protein Interactions Unit, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Sylvia Clausing
- DNA motors group, Biotechnology Center, Technische Universität Dresden, 01062 Dresden, Germany
| | - Mark D. Szczelkun
- DNA-Protein Interactions Unit, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Ralf Seidel
- DNA motors group, Biotechnology Center, Technische Universität Dresden, 01062 Dresden, Germany
- Institute of Molecular Cell Biology, University of Münster, 48149 Münster, Germany
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22
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Roles for Helicases as ATP-Dependent Molecular Switches. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 767:225-44. [PMID: 23161014 DOI: 10.1007/978-1-4614-5037-5_11] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
On the basis of the familial name, a "helicase" might be expected to have an enzymatic activity that unwinds duplex polynucleotides to form single strands. A more encompassing taxonomy that captures alternative enzymatic roles has defined helicases as a sub-class of molecular motors that move directionally and processively along nucleic acids, the so-called "translocases". However, even this definition may be limiting in capturing the full scope of helicase mechanism and activity. Discussed here is another, alternative view of helicases-as machines which couple NTP-binding and hydrolysis to changes in protein conformation to resolve stable nucleoprotein assembly states. This "molecular switch" role differs from the classical view of helicases as molecular motors in that only a single catalytic NTPase cycle may be involved. This is illustrated using results obtained with the DEAD-box family of RNA helicases and with a model bacterial system, the ATP-dependent Type III restriction-modification enzymes. Further examples are discussed and illustrate the wide-ranging examples of molecular switches in genome metabolism.
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23
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Landry MP, Zou X, Wang L, Huang WM, Schulten K, Chemla YR. DNA target sequence identification mechanism for dimer-active protein complexes. Nucleic Acids Res 2012; 41:2416-27. [PMID: 23275566 PMCID: PMC3575837 DOI: 10.1093/nar/gks1345] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Sequence-specific DNA-binding proteins must quickly and reliably localize specific target sites on DNA. This search process has been well characterized for monomeric proteins, but it remains poorly understood for systems that require assembly into dimers or oligomers at the target site. We present a single-molecule study of the target-search mechanism of protelomerase TelK, a recombinase-like protein that is only active as a dimer. We show that TelK undergoes 1D diffusion on non-target DNA as a monomer, and it immobilizes upon dimerization even in the absence of a DNA target site. We further show that dimeric TelK condenses non-target DNA, forming a tightly bound nucleoprotein complex. Together with theoretical calculations and molecular dynamics simulations, we present a novel target-search model for TelK, which may be generalizable to other dimer and oligomer-active proteins.
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Affiliation(s)
- Markita P Landry
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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24
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Mackeldanz P, Alves J, Möncke-Buchner E, Wyszomirski KH, Krüger DH, Reuter M. Functional consequences of mutating conserved SF2 helicase motifs in the Type III restriction endonuclease EcoP15I translocase domain. Biochimie 2012; 95:817-23. [PMID: 23220200 DOI: 10.1016/j.biochi.2012.11.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Accepted: 11/28/2012] [Indexed: 10/27/2022]
Abstract
For efficient DNA hydrolysis, Type III restriction endonuclease EcoP15I interacts with two inversely oriented recognition sites in an ATP-dependent process. EcoP15I consists of two methylation (Mod) subunits and a single restriction (Res) subunit yielding a multifunctional enzyme complex able to methylate or to hydrolyse DNA. Comprehensive sequence alignments, limited proteolysis and mass spectroscopy suggested that the Res subunit is a fusion of a motor or translocase (Tr) domain of superfamily II helicases and an endonuclease domain with a catalytic PD…EXK motif. In the Tr domain, seven predicted helicase motifs (I, Ia, II-VI), a recently discovered Q-tip motif and three additional regions (IIIa, IVa, Va) conserved among Type III restriction enzymes have been identified that are predicted to be involved in DNA binding and ATP hydrolysis. Because DNA unwinding activity for EcoP15I (as for bona fide helicases) has never been found and EcoP15I ATPase rates are only low, the functional importance of the helicase motifs and regions was questionable and has never been probed systematically. Therefore, we mutated all helicase motifs and conserved regions predicted in Type III restriction enzyme EcoP15I and examined the functional consequences on EcoP15I enzyme activity and the structural integrity of the variants by CD spectroscopy. The resulting eleven enzyme variants all, except variant IVa, are properly folded showing the same secondary structure distribution as the wild-type enzyme. Classical helicase motifs I-VI are important for ATP and DNA cleavage by EcoP15I and mutations therein led to complete loss of ATPase and cleavage activity. Among the catalytically inactive enzyme variants three preserved the ability to bind ATP. In contrast, newly assigned motifs Q-tip, Ia and Va are not essential for EcoP15I activity and the corresponding enzyme variants were still catalytically active. DNA binding was only marginally reduced (2-7 fold) in all enzyme variants tested.
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Affiliation(s)
- Petra Mackeldanz
- Institute of Medical Virology, Helmut-Ruska-Haus, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
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25
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Studying genomic processes at the single-molecule level: introducing the tools and applications. Nat Rev Genet 2012; 14:9-22. [DOI: 10.1038/nrg3316] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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26
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De Vlaminck I, Henighan T, van Loenhout MTJ, Burnham DR, Dekker C. Magnetic forces and DNA mechanics in multiplexed magnetic tweezers. PLoS One 2012; 7:e41432. [PMID: 22870220 PMCID: PMC3411724 DOI: 10.1371/journal.pone.0041432] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Accepted: 06/26/2012] [Indexed: 12/02/2022] Open
Abstract
Magnetic tweezers (MT) are a powerful tool for the study of DNA-enzyme interactions. Both the magnet-based manipulation and the camera-based detection used in MT are well suited for multiplexed measurements. Here, we systematically address challenges related to scaling of multiplexed magnetic tweezers (MMT) towards high levels of parallelization where large numbers of molecules (say 103) are addressed in the same amount of time required by a single-molecule measurement. We apply offline analysis of recorded images and show that this approach provides a scalable solution for parallel tracking of the xyz-positions of many beads simultaneously. We employ a large field-of-view imaging system to address many DNA-bead tethers in parallel. We model the 3D magnetic field generated by the magnets and derive the magnetic force experienced by DNA-bead tethers across the large field of view from first principles. We furthermore experimentally demonstrate that a DNA-bead tether subject to a rotating magnetic field describes a bicircular, Limaçon rotation pattern and that an analysis of this pattern simultaneously yields information about the force angle and the position of attachment of the DNA on the bead. Finally, we apply MMT in the high-throughput investigation of the distribution of the induced magnetic moment, the position of attachment of DNA on the beads, and DNA flexibility. The methods described herein pave the way to kilo-molecule level magnetic tweezers experiments.
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Affiliation(s)
- Iwijn De Vlaminck
- Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Thomas Henighan
- Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | | | - Daniel R. Burnham
- Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Cees Dekker
- Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
- * E-mail:
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27
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Affiliation(s)
| | - Cees Dekker
- Kavli Institute of Nanoscience, Delft University of Technology, Delft, 2628 CJ, The Netherlands;
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28
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Gupta YK, Yang L, Chan SH, Samuelson JC, Xu SY, Aggarwal AK. Structural insights into the assembly and shape of Type III restriction-modification (R-M) EcoP15I complex by small-angle X-ray scattering. J Mol Biol 2012; 420:261-8. [PMID: 22560991 DOI: 10.1016/j.jmb.2012.04.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 04/25/2012] [Accepted: 04/27/2012] [Indexed: 11/25/2022]
Abstract
EcoP15I is the prototype of the Type III restriction enzyme family, composed of two modification (Mod) subunits to which two (or one) restriction (Res) subunits are then added. The Mod subunits are responsible for DNA recognition and methylation, while the Res subunits are responsible for ATP hydrolysis and cleavage. Despite extensive biochemical and genetic studies, there is still no structural information on Type III restriction enzymes. We present here small-angle X-ray scattering (SAXS) and analytical ultracentrifugation analysis of the EcoP15I holoenzyme and the Mod(2) subcomplex. We show that the Mod(2) subcomplex has a relatively compact shape with a radius of gyration (R(G)) of ∼37.4 Å and a maximal dimension of ∼110 Å. The holoenzyme adopts an elongated crescent shape with an R(G) of ∼65.3 Å and a maximal dimension of ∼218 Å. From reconstructed SAXS envelopes, we postulate that Mod(2) is likely docked in the middle of the holoenzyme with a Res subunit at each end. We discuss the implications of our model for EcoP15I action, whereby the Res subunits may come together and form a "sliding clamp" around the DNA.
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Affiliation(s)
- Yogesh K Gupta
- Department of Structural and Chemical Biology, Mount Sinai School of Medicine, Box 1677, 1425 Madison Avenue, New York, NY 10029, USA
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29
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Tóth J, van Aelst K, Salmons H, Szczelkun MD. Dissociation from DNA of Type III Restriction-Modification enzymes during helicase-dependent motion and following endonuclease activity. Nucleic Acids Res 2012; 40:6752-64. [PMID: 22523084 PMCID: PMC3413136 DOI: 10.1093/nar/gks328] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
DNA cleavage by the Type III Restriction–Modification (RM) enzymes requires the binding of a pair of RM enzymes at two distant, inversely orientated recognition sequences followed by helicase-catalysed ATP hydrolysis and long-range communication. Here we addressed the dissociation from DNA of these enzymes at two stages: during long-range communication and following DNA cleavage. First, we demonstrated that a communicating species can be trapped in a DNA domain without a recognition site, with a non-specific DNA association lifetime of ∼200 s. If free DNA ends were present the lifetime became too short to measure, confirming that ends accelerate dissociation. Secondly, we observed that Type III RM enzymes can dissociate upon DNA cleavage and go on to cleave further DNA molecules (they can ‘turnover’, albeit inefficiently). The relationship between the observed cleavage rate and enzyme concentration indicated independent binding of each site and a requirement for simultaneous interaction of at least two enzymes per DNA to achieve cleavage. In light of various mechanisms for helicase-driven motion on DNA, we suggest these results are most consistent with a thermally driven random 1D search model (i.e. ‘DNA sliding’).
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Affiliation(s)
- Júlia Tóth
- DNA-Protein Interactions Unit, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
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Loakes D. Nucleotides and nucleic acids; oligo- and polynucleotides. ORGANOPHOSPHORUS CHEMISTRY 2012. [DOI: 10.1039/9781849734875-00169] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- David Loakes
- Medical Research Council Laboratory of Molecular Biology, Hills Road Cambridge CB2 2QH UK
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Wyszomirski KH, Curth U, Alves J, Mackeldanz P, Möncke-Buchner E, Schutkowski M, Krüger DH, Reuter M. Type III restriction endonuclease EcoP15I is a heterotrimeric complex containing one Res subunit with several DNA-binding regions and ATPase activity. Nucleic Acids Res 2011; 40:3610-22. [PMID: 22199260 PMCID: PMC3333885 DOI: 10.1093/nar/gkr1239] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
For efficient DNA cleavage, the Type III restriction endonuclease EcoP15I communicates with two inversely oriented recognition sites in an ATP-dependent process. EcoP15I consists of methylation (Mod) and restriction (Res) subunits forming a multifunctional enzyme complex able to methylate or to cleave DNA. In this study, we determined by different analytical methods that EcoP15I contains a single Res subunit in a Mod(2)Res stoichiometry. The Res subunit comprises a translocase (Tr) domain carrying functional motifs of superfamily 2 helicases and an endonuclease domain with a PD..D/EXK motif. We show that the isolated Tr domain retains ATP-hydrolyzing activity and binds single- and double-stranded DNA in a sequence-independent manner. To localize the regions of DNA binding, we screened peptide arrays representing the entire Res sequence for their ability to interact with DNA. We discovered four DNA-binding regions in the Tr domain and two DNA-binding regions in the endonuclease domain. Modelling of the Tr domain shows that these multiple DNA-binding regions are located on the surface, free to interact with DNA. Interestingly, the positions of the DNA-binding regions are conserved among other Type III restriction endonucleases.
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Affiliation(s)
- Karol H Wyszomirski
- Institute of Medical Virology, Helmut-Ruska-Haus, Charité-Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin,Germany
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Translocation, switching and gating: potential roles for ATP in long-range communication on DNA by Type III restriction endonucleases. Biochem Soc Trans 2011; 39:589-94. [PMID: 21428945 PMCID: PMC3064402 DOI: 10.1042/bst0390589] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
To cleave DNA, the Type III RM (restriction–modification) enzymes must communicate the relative orientation of two recognition sequences, which may be separated by many thousands of base pairs. This long-range interaction requires ATP hydrolysis by a helicase domain, and both active (DNA translocation) and passive (DNA sliding) modes of motion along DNA have been proposed. Potential roles for ATP binding and hydrolysis by the helicase domains are discussed, with a focus on bipartite ATPases that act as molecular switches.
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Schwarz FW, van Aelst K, Tóth J, Seidel R, Szczelkun MD. DNA cleavage site selection by Type III restriction enzymes provides evidence for head-on protein collisions following 1D bidirectional motion. Nucleic Acids Res 2011; 39:8042-51. [PMID: 21724613 PMCID: PMC3185417 DOI: 10.1093/nar/gkr502] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
DNA cleavage by the Type III Restriction–Modification enzymes requires communication in 1D between two distant indirectly-repeated recognitions sites, yet results in non-specific dsDNA cleavage close to only one of the two sites. To test a recently proposed ATP-triggered DNA sliding model, we addressed why one site is selected over another during cleavage. We examined the relative cleavage of a pair of identical sites on DNA substrates with different distances to a free or protein blocked end, and on a DNA substrate using different relative concentrations of protein. Under these conditions a bias can be induced in the cleavage of one site over the other. Monte-Carlo simulations based on the sliding model reproduce the experimentally observed behaviour. This suggests that cleavage site selection simply reflects the dynamics of the preceding stochastic enzyme events that are consistent with bidirectional motion in 1D and DNA cleavage following head-on protein collision.
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Affiliation(s)
- Friedrich W Schwarz
- Biotechnology Center, Dresden University of Technology, 01062 Dresden, Germany
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Dryden DTF, Edwardson JM, Henderson RM. DNA translocation by type III restriction enzymes: a comparison of current models of their operation derived from ensemble and single-molecule measurements. Nucleic Acids Res 2011; 39:4525-31. [PMID: 21310716 PMCID: PMC3113558 DOI: 10.1093/nar/gkq1285] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Much insight into the interactions of DNA and enzymes has been obtained using a number of single-molecule techniques. However, recent results generated using two of these techniques-atomic force microscopy (AFM) and magnetic tweezers (MT)-have produced apparently contradictory results when applied to the action of the ATP-dependent type III restriction endonucleases on DNA. The AFM images show extensive looping of the DNA brought about by the existence of multiple DNA binding sites on each enzyme and enzyme dimerisation. The MT experiments show no evidence for looping being a requirement for DNA cleavage, but instead support a diffusive sliding of the enzyme on the DNA until an enzyme-enzyme collision occurs, leading to cleavage. Not only do these two methods appear to disagree, but also the models derived from them have difficulty explaining some ensemble biochemical results on DNA cleavage. In this 'Survey and Summary', we describe several different models put forward for the action of type III restriction enzymes and their inadequacies. We also attempt to reconcile the different models and indicate areas for further experimentation to elucidate the mechanism of these enzymes.
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Affiliation(s)
- David T F Dryden
- School of Chemistry, The King's Buildings, The University of Edinburgh, Edinburgh, EH9 3JJ, UK.
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Ishikawa K, Fukuda E, Kobayashi I. Conflicts targeting epigenetic systems and their resolution by cell death: novel concepts for methyl-specific and other restriction systems. DNA Res 2010; 17:325-42. [PMID: 21059708 PMCID: PMC2993543 DOI: 10.1093/dnares/dsq027] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Epigenetic modification of genomic DNA by methylation is important for defining the epigenome and the transcriptome in eukaryotes as well as in prokaryotes. In prokaryotes, the DNA methyltransferase genes often vary, are mobile, and are paired with the gene for a restriction enzyme. Decrease in a certain epigenetic methylation may lead to chromosome cleavage by the partner restriction enzyme, leading to eventual cell death. Thus, the pairing of a DNA methyltransferase and a restriction enzyme forces an epigenetic state to be maintained within the genome. Although restriction enzymes were originally discovered for their ability to attack invading DNAs, it may be understood because such DNAs show deviation from this epigenetic status. DNAs with epigenetic methylation, by a methyltransferase linked or unlinked with a restriction enzyme, can also be the target of DNases, such as McrBC of Escherichia coli, which was discovered because of its methyl-specific restriction. McrBC responds to specific genome methylation systems by killing the host bacterial cell through chromosome cleavage. Evolutionary and genomic analysis of McrBC homologues revealed their mobility and wide distribution in prokaryotes similar to restriction–modification systems. These findings support the hypothesis that this family of methyl-specific DNases evolved as mobile elements competing with specific genome methylation systems through host killing. These restriction systems clearly demonstrate the presence of conflicts between epigenetic systems.
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Affiliation(s)
- Ken Ishikawa
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, Japan
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