1
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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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Tuck OT, Adler BA, Armbruster EG, Lahiri A, Hu JJ, Zhou J, Pogliano J, Doudna JA. Hachiman is a genome integrity sensor. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.29.582594. [PMID: 38464307 PMCID: PMC10925250 DOI: 10.1101/2024.02.29.582594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Hachiman is a broad-spectrum antiphage defense system of unknown function. We show here that Hachiman comprises a heterodimeric nuclease-helicase complex, HamAB. HamA, previously a protein of unknown function, is the effector nuclease. HamB is the sensor helicase. HamB constrains HamA activity during surveillance of intact dsDNA. When the HamAB complex detects DNA damage, HamB helicase activity liberates HamA, unleashing nuclease activity. Hachiman activation degrades all DNA in the cell, creating 'phantom' cells devoid of both phage and host DNA. We demonstrate Hachiman activation in the absence of phage by treatment with DNA-damaging agents, suggesting that Hachiman responds to aberrant DNA states. Phylogenetic similarities between the Hachiman helicase and eukaryotic enzymes suggest this bacterial immune system has been repurposed for diverse functions across all domains of life.
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Affiliation(s)
- Owen T. Tuck
- Department of Chemistry, University of California, Berkeley, Berkeley, CA USA
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA USA
| | - Benjamin A. Adler
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, CA USA
| | - Emily G. Armbruster
- School of Biological Sciences, University of California San Diego, La Jolla, CA USA
| | - Arushi Lahiri
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California USA
| | - Jason J. Hu
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California USA
| | - Julia Zhou
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California USA
| | - Joe Pogliano
- School of Biological Sciences, University of California San Diego, La Jolla, CA USA
| | - Jennifer A. Doudna
- Department of Chemistry, University of California, Berkeley, Berkeley, CA USA
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, CA USA
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California USA
- Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA USA
- MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA USA
- Gladstone Institutes, University of California, San Francisco, San Francisco, CA USA
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA USA
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3
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Jung J, Kim S, Rah SH, Lee J, Shon MJ. Force-fluorescence setup for observing protein-DNA interactions under load. Methods Enzymol 2024; 694:137-165. [PMID: 38492949 DOI: 10.1016/bs.mie.2024.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2024]
Abstract
This chapter explores advanced single-molecule techniques for studying protein-DNA interactions, particularly focusing on Replication Protein A (RPA) using a force-fluorescence setup. It combines magnetic tweezers (MT) with total internal reflection fluorescence (TIRF) microscopy, enabling detailed observation of DNA behavior under mechanical stress. The chapter details the use of DNA hairpins and bare DNA to examine RPA's binding dynamics and its influence on DNA's mechanical properties. This approach provides deeper insights into RPA's role in DNA replication, repair, and recombination, highlighting its significance in maintaining genomic stability.
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Affiliation(s)
- Jaehun Jung
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
| | - Subin Kim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
| | - Sang-Hyun Rah
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
| | - Jayil Lee
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea; Institute of Basic Science Center for Genomic Integrity, Ulsan, Republic of Korea
| | - Min Ju Shon
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea; School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea.
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4
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Madariaga-Marcos J, Aldag P, Kauert DJ, Seidel R. Correlated Single-Molecule Magnetic Tweezers and Fluorescence Measurements of DNA-Enzyme Interactions. Methods Mol Biol 2024; 2694:421-449. [PMID: 37824016 DOI: 10.1007/978-1-0716-3377-9_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
Combining force spectroscopy and fluorescence microscopy provides a substantial improvement to the single-molecule toolbox by allowing simultaneous manipulation and orthogonal characterizations of the conformations, interactions, and activity of biomolecular complexes. Here, we describe a combined magnetic tweezers and total internal reflection fluorescence microscopy setup to carry out correlated single-molecule fluorescence spectroscopy and force/twisting experiments. We apply the setup to reveal the DNA interactions of the CRISPR-Cas surveillance complex Cascade. Single-molecule fluorescence of a labeled Cascade allows to follow the DNA association and dissociation of the protein. Simultaneously, the magnetic tweezers probe the DNA unwinding during R-loop formation by the bound Cascade complexes. Furthermore, the setup supports observation of 1D diffusion of protein complexes on stretched DNA molecules. This technique can be applied to study a vast range of protein-DNA interactions.
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Affiliation(s)
- Julene Madariaga-Marcos
- Molecular Biophysics Group, Peter Debye Institute for Soft Matter Physics, Universität Leipzig, Leipzig, Germany
| | - Pierre Aldag
- Molecular Biophysics Group, Peter Debye Institute for Soft Matter Physics, Universität Leipzig, Leipzig, Germany
| | - Dominik J Kauert
- Molecular Biophysics Group, Peter Debye Institute for Soft Matter Physics, Universität Leipzig, Leipzig, Germany
| | - Ralf Seidel
- Molecular Biophysics Group, Peter Debye Institute for Soft Matter Physics, Universität Leipzig, Leipzig, Germany.
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5
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Dulin D. An Introduction to Magnetic Tweezers. Methods Mol Biol 2024; 2694:375-401. [PMID: 37824014 DOI: 10.1007/978-1-0716-3377-9_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
Magnetic tweezers are a single-molecule force and torque spectroscopy technique that enable the mechanical interrogation in vitro of biomolecules, such as nucleic acids and proteins. They use a magnetic field originating from either permanent magnets or electromagnets to attract a magnetic particle, thus stretching the tethering biomolecule. They nicely complement other force spectroscopy techniques such as optical tweezers and atomic force microscopy (AFM) as they operate as a very stable force clamp, enabling long-duration experiments over a very broad range of forces spanning from 10 fN to 1 nN, with 1-10 milliseconds time and sub-nanometer spatial resolution. Their simplicity, robustness, and versatility have made magnetic tweezers a key technique within the field of single-molecule biophysics, being broadly applied to study the mechanical properties of, e.g., nucleic acids, genome processing molecular motors, protein folding, and nucleoprotein filaments. Furthermore, magnetic tweezers allow for high-throughput single-molecule measurements by tracking hundreds of biomolecules simultaneously both in real-time and at high spatiotemporal resolution. Magnetic tweezers naturally combine with surface-based fluorescence spectroscopy techniques, such as total internal reflection fluorescence microscopy, enabling correlative fluorescence and force/torque spectroscopy on biomolecules. This chapter presents an introduction to magnetic tweezers including a description of the hardware, the theory behind force calibration, its spatiotemporal resolution, combining it with other techniques, and a (non-exhaustive) overview of biological applications.
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Affiliation(s)
- David Dulin
- LaserLaB Amsterdam and Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.
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6
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Aldag P, Rutkauskas M, Madariaga-Marcos J, Songailiene I, Sinkunas T, Kemmerich F, Kauert D, Siksnys V, Seidel R. Dynamic interplay between target search and recognition for a Type I CRISPR-Cas system. Nat Commun 2023; 14:3654. [PMID: 37339984 PMCID: PMC10281945 DOI: 10.1038/s41467-023-38790-1] [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: 12/12/2022] [Accepted: 05/16/2023] [Indexed: 06/22/2023] Open
Abstract
CRISPR-Cas effector complexes enable the defense against foreign nucleic acids and have recently been exploited as molecular tools for precise genome editing at a target locus. To bind and cleave their target, the CRISPR-Cas effectors have to interrogate the entire genome for the presence of a matching sequence. Here we dissect the target search and recognition process of the Type I CRISPR-Cas complex Cascade by simultaneously monitoring DNA binding and R-loop formation by the complex. We directly quantify the effect of DNA supercoiling on the target recognition probability and demonstrate that Cascade uses facilitated diffusion for its target search. We show that target search and target recognition are tightly linked and that DNA supercoiling and limited 1D diffusion need to be considered when understanding target recognition and target search by CRISPR-Cas enzymes and engineering more efficient and precise variants.
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Affiliation(s)
- Pierre Aldag
- Peter Debye Institute for Soft Matter Physics, Universität Leipzig, 04103, Leipzig, Germany
| | - Marius Rutkauskas
- Peter Debye Institute for Soft Matter Physics, Universität Leipzig, 04103, Leipzig, Germany
| | | | - Inga Songailiene
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekis ave. 7, Vilnius, 10257, Lithuania
| | - Tomas Sinkunas
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekis ave. 7, Vilnius, 10257, Lithuania
| | - Felix Kemmerich
- Peter Debye Institute for Soft Matter Physics, Universität Leipzig, 04103, Leipzig, Germany
| | - Dominik Kauert
- Peter Debye Institute for Soft Matter Physics, Universität Leipzig, 04103, Leipzig, Germany
| | - Virginijus Siksnys
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekis ave. 7, Vilnius, 10257, Lithuania.
| | - Ralf Seidel
- Peter Debye Institute for Soft Matter Physics, Universität Leipzig, 04103, Leipzig, Germany.
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7
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Zhang A, Friedman LJ, Gelles J, Bell SP. Changing protein-DNA interactions promote ORC binding site exchange during replication origin licensing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.16.545300. [PMID: 37398123 PMCID: PMC10312730 DOI: 10.1101/2023.06.16.545300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
During origin licensing, the eukaryotic replicative helicase Mcm2-7 forms head-to-head double hexamers to prime origins for bidirectional replication. Recent single-molecule and structural studies revealed that one molecule of the helicase loader ORC can sequentially load two Mcm2-7 hexamers to ensure proper head-to-head helicase alignment. To perform this task, ORC must release from its initial high-affinity DNA binding site and "flip" to bind a weaker, inverted DNA site. However, the mechanism of this binding-site switch remains unclear. In this study, we used single-molecule Förster resonance energy transfer (sm-FRET) to study the changing interactions between DNA and ORC or Mcm2-7. We found that the loss of DNA bending that occurs during DNA deposition into the Mcm2-7 central channel increases the rate of ORC dissociation from DNA. Further studies revealed temporally-controlled DNA sliding of helicase-loading intermediates, and that the first sliding complex includes ORC, Mcm2-7, and Cdt1. We demonstrate that sequential events of DNA unbending, Cdc6 release, and sliding lead to a stepwise decrease in ORC stability on DNA, facilitating ORC dissociation from its strong binding site during site switching. In addition, the controlled sliding we observed provides insight into how ORC accesses secondary DNA binding sites at different locations relative to the initial binding site. Our study highlights the importance of dynamic protein-DNA interactions in the loading of two oppositely-oriented Mcm2-7 helicases to ensure bidirectional DNA replication. Significance Statement Bidirectional DNA replication, in which two replication forks travel in opposite directions from each origin of replication, is required for complete genome duplication. To prepare for this event, two copies of the Mcm2-7 replicative helicase are loaded at each origin in opposite orientations. Using single-molecule assays, we studied the sequence of changing protein-DNA interactions involved in this process. These stepwise changes gradually reduce the DNA-binding strength of ORC, the primary DNA binding protein involved in this event. This reduced affinity promotes ORC dissociation and rebinding in the opposite orientation on the DNA, facilitating the sequential assembly of two Mcm2-7 molecules in opposite orientations. Our findings identify a coordinated series of events that drive proper DNA replication initiation.
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Affiliation(s)
- Annie Zhang
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Larry J. Friedman
- Department of Biochemistry, Brandeis University, Waltham, MA 02454, USA
| | - Jeff Gelles
- Department of Biochemistry, Brandeis University, Waltham, MA 02454, USA
| | - Stephen P Bell
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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8
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Ramírez Montero D, Sánchez H, van Veen E, van Laar T, Solano B, Diffley JFX, Dekker NH. Nucleotide binding halts diffusion of the eukaryotic replicative helicase during activation. Nat Commun 2023; 14:2082. [PMID: 37059705 PMCID: PMC10104875 DOI: 10.1038/s41467-023-37093-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 03/02/2023] [Indexed: 04/16/2023] Open
Abstract
The eukaryotic replicative helicase CMG centrally orchestrates the replisome and leads the way at the front of replication forks. Understanding the motion of CMG on the DNA is therefore key to our understanding of DNA replication. In vivo, CMG is assembled and activated through a cell-cycle-regulated mechanism involving 36 polypeptides that has been reconstituted from purified proteins in ensemble biochemical studies. Conversely, single-molecule studies of CMG motion have thus far relied on pre-formed CMG assembled through an unknown mechanism upon overexpression of individual constituents. Here, we report the activation of CMG fully reconstituted from purified yeast proteins and the quantification of its motion at the single-molecule level. We observe that CMG can move on DNA in two ways: by unidirectional translocation and by diffusion. We demonstrate that CMG preferentially exhibits unidirectional translocation in the presence of ATP, whereas it preferentially exhibits diffusive motion in the absence of ATP. We also demonstrate that nucleotide binding halts diffusive CMG independently of DNA melting. Taken together, our findings support a mechanism by which nucleotide binding allows newly assembled CMG to engage with the DNA within its central channel, halting its diffusion and facilitating the initial DNA melting required to initiate DNA replication.
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Affiliation(s)
- Daniel Ramírez Montero
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Humberto Sánchez
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Edo van Veen
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Theo van Laar
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Belén Solano
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - John F X Diffley
- Chromosome Replication Laboratory, Francis Crick Institute, London, UK.
| | - Nynke H Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands.
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9
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Geyer VF, Diez S. Horizontal Magnetic Tweezers to Directly Measure the Force-Velocity Relationship for Multiple Kinesin Motors. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023:e2300558. [PMID: 37035988 DOI: 10.1002/smll.202300558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 03/11/2023] [Indexed: 06/19/2023]
Abstract
Transport of intracellular cargo along cytoskeletal filaments is often achieved by the concerted action of multiple motor molecules. While single-molecule studies have provided profound insight into the mechano-chemical principles and force generation of individual motors, studies on multi-motor systems are less advanced. Here, a horizontal magnetic-tweezers setup is applied, capable of producing up to 150 pN of horizontal force onto 2.8 µm superparamagnetic beads, to motor-propelled cytoskeletal filaments. It is found that kinesin-1 driven microtubules decorated with individual beads display frequent transitions in their gliding velocities which we attribute to dynamic changes in the number of engaged motors. Applying defined temporal force-ramps the force-velocity relationship is directly measured for multi-motor transport. It is found that the stall forces of individual motors are approximately additive and collective backward motion of the transport system under super-stall forces is observed. The magnetic-tweezers apparatus is expected to be readily applicable to a wide range of molecular and cellular motility assays.
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Affiliation(s)
- Veikko F Geyer
- B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, Tatzberg 41, 01307, Dresden, Germany
| | - Stefan Diez
- B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, Tatzberg 41, 01307, Dresden, Germany
- Cluster of Excellence Physics of Life, Technische Universität Dresden, Arnoldstraße 18, 01307, Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307, Dresden, Germany
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10
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A quantitative model for the dynamics of target recognition and off-target rejection by the CRISPR-Cas Cascade complex. Nat Commun 2022; 13:7460. [PMID: 36460652 PMCID: PMC9718816 DOI: 10.1038/s41467-022-35116-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 11/18/2022] [Indexed: 12/05/2022] Open
Abstract
CRISPR-Cas effector complexes recognise nucleic acid targets by base pairing with their crRNA which enables easy re-programming of the target specificity in rapidly emerging genome engineering applications. However, undesired recognition of off-targets, that are only partially complementary to the crRNA, occurs frequently and represents a severe limitation of the technique. Off-targeting lacks comprehensive quantitative understanding and prediction. Here, we present a detailed analysis of the target recognition dynamics by the Cascade surveillance complex on a set of mismatched DNA targets using single-molecule supercoiling experiments. We demonstrate that the observed dynamics can be quantitatively modelled as a random walk over the length of the crRNA-DNA hybrid using a minimal set of parameters. The model accurately describes the recognition of targets with single and double mutations providing an important basis for quantitative off-target predictions. Importantly the model intrinsically accounts for observed bias regarding the position and the proximity between mutations and reveals that the seed length for the initiation of target recognition is controlled by DNA supercoiling rather than the Cascade structure.
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11
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Helwer R, Charette JM. The SSU Processome Component Utp25p is a Pseudohelicase. MICROPUBLICATION BIOLOGY 2022; 2022:10.17912/micropub.biology.000606. [PMID: 36212518 PMCID: PMC9539457 DOI: 10.17912/micropub.biology.000606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 08/19/2022] [Accepted: 09/19/2022] [Indexed: 11/09/2022]
Abstract
RNA helicases are involved in nearly all aspects of RNA metabolism and factor prominently in ribosome assembly. The SSU processome includes 10 helicases and many helicase-cofactors. Together, they mediate the structural rearrangements that occur as part of ribosomal SSU assembly. During the identification of the SSU processome component Utp25/Def, it was noticed that the protein displays some sequence similarity to DEAD-box RNA helicases and is essential for growth. Interestingly, mutational ablation showed that Utp25's DEAD-box motifs are dispensable. Here, we show that the Utp25 AlphaFold prediction displays considerable structural similarity to DEAD-box helicases and is the first fully validated pseudohelicase.
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Affiliation(s)
- Rafe Helwer
- Department of Chemistry, Brandon University, Brandon, Manitoba, Canada.
,
Children’s Hospital Research Institute of Manitoba, Winnipeg, Manitoba, Canada.
,
CancerCare Manitoba Research Institute, Winnipeg, Manitoba, Canada
| | - J. Michael Charette
- Department of Chemistry, Brandon University, Brandon, Manitoba, Canada.
,
Children’s Hospital Research Institute of Manitoba, Winnipeg, Manitoba, Canada.
,
CancerCare Manitoba Research Institute, Winnipeg, Manitoba, Canada.
,
Correspondence to: J. Michael Charette (
)
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12
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Cross SJ, Brown CE, Baumann CG. Transverse Magnetic Tweezers Allowing Coincident Epi-Fluorescence Microscopy on Horizontally Extended DNA. Methods Mol Biol 2022; 2476:75-93. [PMID: 35635698 DOI: 10.1007/978-1-0716-2221-6_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Longitudinal magnetic tweezers (L-MT) have seen wide-scale adoption as the tool of choice for stretching and twisting a single DNA molecule. They are also used to probe topological changes in DNA as a result of protein binding and enzymatic activity. However, in the longitudinal configuration, the DNA molecule is extended perpendicular to the imaging plane. As a result, it is only possible to infer biological activity from the motion of the tethered paramagnetic microsphere. Described here is a "transverse" magnetic tweezers (T-MT) geometry featuring simultaneous control of DNA extension and spatially coincident video-rate epi-fluorescence imaging. Unlike in L-MT, DNA tethers in T-MT are extended parallel to the imaging plane between two micron-sized spheres, and importantly protein targets on the DNA can be localized using fluorescent nanoparticles. The T-MT can manipulate a long DNA construct at molecular extensions approaching the contour length defined by B-DNA helical geometry, and the measured entropic elasticity agrees with the wormlike chain model (force <35 pN). By incorporating a torsionally constrained DNA tether, the T-MT would allow both the relative extension and twist of the tether to be manipulated, while viewing far-red emitting fluorophore-labeled targets. This T-MT design has the potential to enable the study of DNA binding and remodeling processes under conditions of constant force and defined torsional stress.
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13
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Aldag P, Welzel F, Jakob L, Schmidbauer A, Rutkauskas M, Fettes F, Grohmann D, Seidel R. Probing the stability of the SpCas9-DNA complex after cleavage. Nucleic Acids Res 2021; 49:12411-12421. [PMID: 34792162 PMCID: PMC8643700 DOI: 10.1093/nar/gkab1072] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 10/14/2021] [Accepted: 10/20/2021] [Indexed: 12/26/2022] Open
Abstract
CRISPR-Cas9 is a ribonucleoprotein complex that sequence-specifically binds and cleaves double-stranded DNA. Wildtype Cas9 and its nickase and cleavage-incompetent mutants have been used in various biological techniques due to their versatility and programmable specificity. Cas9 has been shown to bind very stably to DNA even after cleavage of the individual DNA strands, inhibiting further turnovers and considerably slowing down in-vivo repair processes. This poses an obstacle in genome editing applications. Here, we employed single-molecule magnetic tweezers to investigate the binding stability of different Streptococcus pyogenes Cas9 variants after cleavage by challenging them with supercoiling. We find that different release mechanisms occur depending on which DNA strand is cleaved. After initial target strand cleavage, supercoils are only removed after the collapse of the R-loop. We identified several states with different stabilities of the R-loop. Most importantly, we find that the post-cleavage state of Cas9 exhibits a higher stability than the pre-cleavage state. After non-target strand cleavage, supercoils are immediately but slowly released by swiveling of the non-target strand around Cas9 bound to the target strand. Consequently, Cas9 and its non-target strand nicking mutant stay stably bound to the DNA for many hours even at elevated torsional stress.
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Affiliation(s)
- Pierre Aldag
- Peter Debye Institute for Soft Matter Physics, University of Leipzig, Leipzig 04103, Germany
| | - Fabian Welzel
- Peter Debye Institute for Soft Matter Physics, University of Leipzig, Leipzig 04103, Germany
| | - Leonhard Jakob
- Institute of Microbiology & Archaea Centre, Single-Molecule Biochemistry Lab, University of Regensburg, Regensburg 93053, Germany
| | - Andreas Schmidbauer
- Institute of Microbiology & Archaea Centre, Single-Molecule Biochemistry Lab, University of Regensburg, Regensburg 93053, Germany
| | - Marius Rutkauskas
- Peter Debye Institute for Soft Matter Physics, University of Leipzig, Leipzig 04103, Germany
| | - Fergus Fettes
- Peter Debye Institute for Soft Matter Physics, University of Leipzig, Leipzig 04103, Germany
| | - Dina Grohmann
- Institute of Microbiology & Archaea Centre, Single-Molecule Biochemistry Lab, University of Regensburg, Regensburg 93053, Germany
- Regensburg Center of Biochemistry (RCB), University of Regensburg, 93053 Regensburg, Germany
| | - Ralf Seidel
- Peter Debye Institute for Soft Matter Physics, University of Leipzig, Leipzig 04103, Germany
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14
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Abrosimova LA, Kuznetsov NA, Astafurova NA, Samsonova AR, Karpov AS, Perevyazova TA, Oretskaya TS, Fedorova OS, Kubareva EA. Kinetic Analysis of the Interaction of Nicking Endonuclease BspD6I with DNA. Biomolecules 2021; 11:1420. [PMID: 34680052 PMCID: PMC8533099 DOI: 10.3390/biom11101420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/22/2021] [Accepted: 09/24/2021] [Indexed: 12/03/2022] Open
Abstract
Nicking endonucleases (NEs) are enzymes that incise only one strand of the duplex to produce a DNA molecule that is 'nicked' rather than cleaved in two. Since these precision tools are used in genetic engineering and genome editing, information about their mechanism of action at all stages of DNA recognition and phosphodiester bond hydrolysis is essential. For the first time, fast kinetics of the Nt.BspD6I interaction with DNA were studied by the stopped-flow technique, and changes of optical characteristics were registered for the enzyme or DNA molecules. The role of divalent metal cations was estimated at all steps of Nt.BspD6I-DNA complex formation. It was demonstrated that divalent metal ions are not required for the formation of a non-specific complex of the protein with DNA. Nt.BspD6I bound five-fold more efficiently to its recognition site in DNA than to a random DNA. DNA bending was confirmed during the specific binding of Nt.BspD6I to a substrate. The optimal size of Nt.BspD6I's binding site in DNA as determined in this work should be taken into account in methods of detection of nucleic acid sequences and/or even various base modifications by means of NEs.
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Affiliation(s)
- Liudmila A. Abrosimova
- Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia; (N.A.A.); (A.S.K.)
| | - Nikita A. Kuznetsov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, Lavrentiev Avenue 8, 630090 Novosibirsk, Russia;
| | - Natalia A. Astafurova
- Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia; (N.A.A.); (A.S.K.)
| | | | - Andrey S. Karpov
- Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia; (N.A.A.); (A.S.K.)
| | - Tatiana A. Perevyazova
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Str. 3, 142290 Puschino, Russia;
| | - Tatiana S. Oretskaya
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia; (T.S.O.); (E.A.K.)
| | - Olga S. Fedorova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, Lavrentiev Avenue 8, 630090 Novosibirsk, Russia;
| | - Elena A. Kubareva
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia; (T.S.O.); (E.A.K.)
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15
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Kamagata K, Itoh Y, Tan C, Mano E, Wu Y, Mandali S, Takada S, Johnson RC. Testing mechanisms of DNA sliding by architectural DNA-binding proteins: dynamics of single wild-type and mutant protein molecules in vitro and in vivo. Nucleic Acids Res 2021; 49:8642-8664. [PMID: 34352099 PMCID: PMC8421229 DOI: 10.1093/nar/gkab658] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 07/10/2021] [Accepted: 07/22/2021] [Indexed: 01/06/2023] Open
Abstract
Architectural DNA-binding proteins (ADBPs) are abundant constituents of eukaryotic or bacterial chromosomes that bind DNA promiscuously and function in diverse DNA reactions. They generate large conformational changes in DNA upon binding yet can slide along DNA when searching for functional binding sites. Here we investigate the mechanism by which ADBPs diffuse on DNA by single-molecule analyses of mutant proteins rationally chosen to distinguish between rotation-coupled diffusion and DNA surface sliding after transient unbinding from the groove(s). The properties of yeast Nhp6A mutant proteins, combined with molecular dynamics simulations, suggest Nhp6A switches between two binding modes: a static state, in which the HMGB domain is bound within the minor groove with the DNA highly bent, and a mobile state, where the protein is traveling along the DNA surface by means of its flexible N-terminal basic arm. The behaviors of Fis mutants, a bacterial nucleoid-associated helix-turn-helix dimer, are best explained by mobile proteins unbinding from the major groove and diffusing along the DNA surface. Nhp6A, Fis, and bacterial HU are all near exclusively associated with the chromosome, as packaged within the bacterial nucleoid, and can be modeled by three diffusion modes where HU exhibits the fastest and Fis the slowest diffusion.
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Affiliation(s)
- Kiyoto Kamagata
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
| | - Yuji Itoh
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
| | - Cheng Tan
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Eriko Mano
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
| | - Yining Wu
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
| | - Sridhar Mandali
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1737, USA
| | - Shoji Takada
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Reid C Johnson
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1737, USA.,Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
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16
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Ahmadi A, Till K, Backe PH, Blicher P, Diekmann R, Schüttpelz M, Glette K, Tørresen J, Bjørås M, Rowe AD, Dalhus B. Non-flipping DNA glycosylase AlkD scans DNA without formation of a stable interrogation complex. Commun Biol 2021; 4:876. [PMID: 34267321 PMCID: PMC8282808 DOI: 10.1038/s42003-021-02400-x] [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] [Received: 10/01/2020] [Accepted: 06/25/2021] [Indexed: 11/09/2022] Open
Abstract
The multi-step base excision repair (BER) pathway is initiated by a set of enzymes, known as DNA glycosylases, able to scan DNA and detect modified bases among a vast number of normal bases. While DNA glycosylases in the BER pathway generally bend the DNA and flip damaged bases into lesion specific pockets, the HEAT-like repeat DNA glycosylase AlkD detects and excises bases without sequestering the base from the DNA helix. We show by single-molecule tracking experiments that AlkD scans DNA without forming a stable interrogation complex. This contrasts with previously studied repair enzymes that need to flip bases into lesion-recognition pockets and form stable interrogation complexes. Moreover, we show by design of a loss-of-function mutant that the bimodality in scanning observed for the structural homologue AlkF is due to a key structural differentiator between AlkD and AlkF; a positively charged β-hairpin able to protrude into the major groove of DNA.
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Affiliation(s)
- Arash Ahmadi
- Department of Medical Biochemistry, Institute for Clinical Medicine, University of Oslo, Oslo, Norway
| | - Katharina Till
- FOM Institute AMOLF, Science Park 104, Amsterdam, The Netherlands.,Biomolecular Photonics, Department of Physics, University of Bielefeld, Bielefeld, Germany
| | - Paul Hoff Backe
- Department of Medical Biochemistry, Institute for Clinical Medicine, University of Oslo, Oslo, Norway.,Department of Microbiology, Oslo University Hospital HF, Rikshospitalet and University of Oslo, Oslo, Norway
| | - Pernille Blicher
- Department of Medical Biochemistry, Institute for Clinical Medicine, University of Oslo, Oslo, Norway
| | - Robin Diekmann
- Biomolecular Photonics, Department of Physics, University of Bielefeld, Bielefeld, Germany
| | - Mark Schüttpelz
- Biomolecular Photonics, Department of Physics, University of Bielefeld, Bielefeld, Germany
| | - Kyrre Glette
- Department of Informatics, University of Oslo, Oslo, Norway
| | - Jim Tørresen
- Department of Informatics, University of Oslo, Oslo, Norway
| | - Magnar Bjørås
- Department of Microbiology, Oslo University Hospital HF, Rikshospitalet and University of Oslo, Oslo, Norway.,Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Alexander D Rowe
- Department of Medical Biochemistry, Institute for Clinical Medicine, University of Oslo, Oslo, Norway.,Department of Newborn Screening, Division of Child and Adolescent Medicine, Oslo University Hospital, Oslo, Norway
| | - Bjørn Dalhus
- Department of Medical Biochemistry, Institute for Clinical Medicine, University of Oslo, Oslo, Norway. .,Department of Microbiology, Oslo University Hospital HF, Rikshospitalet and University of Oslo, Oslo, Norway.
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17
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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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18
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García-Bayona L, Coyne MJ, Comstock LE. Mobile Type VI secretion system loci of the gut Bacteroidales display extensive intra-ecosystem transfer, multi-species spread and geographical clustering. PLoS Genet 2021; 17:e1009541. [PMID: 33901198 PMCID: PMC8102008 DOI: 10.1371/journal.pgen.1009541] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 05/06/2021] [Accepted: 04/08/2021] [Indexed: 02/07/2023] Open
Abstract
The human gut microbiota is a dense microbial ecosystem with extensive opportunities for bacterial contact-dependent processes such as conjugation and Type VI secretion system (T6SS)-dependent antagonism. In the gut Bacteroidales, two distinct genetic architectures of T6SS loci, GA1 and GA2, are contained on Integrative and Conjugative Elements (ICE). Despite intense interest in the T6SSs of the gut Bacteroidales, there is only a superficial understanding of their evolutionary patterns, and of their dissemination among Bacteroidales species in human gut communities. Here, we combine extensive genomic and metagenomic analyses to better understand their ecological and evolutionary dynamics. We identify new genetic subtypes, document extensive intrapersonal transfer of these ICE to Bacteroidales species within human gut microbiomes, and most importantly, reveal frequent population fixation of these newly armed strains in multiple species within a person. We further show the distribution of each of the distinct T6SSs in human populations and show there is geographical clustering. We reveal that the GA1 T6SS ICE integrates at a minimal recombination site leading to their integration throughout genomes and their frequent interruption of genes, whereas the GA2 T6SS ICE integrate at one of three different tRNA genes. The exclusion of concurrent GA1 and GA2 T6SSs in individual strains is associated with intact T6SS loci and with an ICE-encoded gene. By performing a comprehensive analysis of mobile genetic elements (MGE) in co-resident Bacteroidales species in numerous human gut communities, we identify 74 MGE that transferred to multiple Bacteroidales species within individual gut microbiomes. We further show that only three other MGE demonstrate multi-species spread in human gut microbiomes to the degree demonstrated by the GA1 and GA2 ICE. These data underscore the ubiquity and dissemination of mobile T6SS loci within Bacteroidales communities and across human populations.
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Affiliation(s)
- Leonor García-Bayona
- Division of Infectious Diseases, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Michael J. Coyne
- Division of Infectious Diseases, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Laurie E. Comstock
- Division of Infectious Diseases, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
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19
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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] [MESH Headings] [Grants] [Track Full Text] [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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20
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Hosford CJ, Adams MC, Niu Y, Chappie JS. The N-terminal domain of Staphylothermus marinus McrB shares structural homology with PUA-like RNA binding proteins. J Struct Biol 2020; 211:107572. [PMID: 32652237 DOI: 10.1016/j.jsb.2020.107572] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 07/01/2020] [Accepted: 07/02/2020] [Indexed: 12/27/2022]
Abstract
McrBC is a conserved modification-dependent restriction system that in Escherichia coli specifically targets foreign DNA containing methylated cytosines. Crystallographic data show that the N-terminal domain of Escherichia coli McrB binds substrates via a base flipping mechanism. This region is poorly conserved among the plethora of McrB homologs, suggesting that other species may use alternative binding strategies and/or recognize different targets. Here we present the crystal structure of the N-terminal domain from Stayphlothermus marinus McrB (Sm3-180) at 1.92 Å, which adopts a PUA-like EVE fold that is closely related to the YTH and ASCH RNA binding domains. Unlike most PUA-like domains, Sm3-180 binds DNA and can associate with different modified substrates. We find the canonical 'aromatic cage' binding pocket that confers specificity for methylated bases in other EVE/YTH domains is degenerate and occluded in Sm3-180, which may contribute to its promiscuity in target recognition. Further structural comparison between different PUA-like domains identifies motifs and conformational variations that correlate with the preference for binding either DNA or RNA. Together these data have important implications for PUA-like domain specificity and suggest a broader biological versatility for the McrBC family than previously described.
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Affiliation(s)
| | - Myfanwy C Adams
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Yiming Niu
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Joshua S Chappie
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA.
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21
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Krivoy A, Rutkauskas M, Kuznedelov K, Musharova O, Rouillon C, Severinov K, Seidel R. Primed CRISPR adaptation in Escherichia coli cells does not depend on conformational changes in the Cascade effector complex detected in Vitro. Nucleic Acids Res 2019; 46:4087-4098. [PMID: 29596641 PMCID: PMC5934681 DOI: 10.1093/nar/gky219] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 03/14/2018] [Indexed: 11/13/2022] Open
Abstract
In type I CRISPR-Cas systems, primed adaptation of new spacers into CRISPR arrays occurs when the effector Cascade-crRNA complex recognizes imperfectly matched targets that are not subject to efficient CRISPR interference. Thus, primed adaptation allows cells to acquire additional protection against mobile genetic elements that managed to escape interference. Biochemical and biophysical studies suggested that Cascade-crRNA complexes formed on fully matching targets (subject to efficient interference) and on partially mismatched targets that promote primed adaption are structurally different. Here, we probed Escherichia coli Cascade-crRNA complexes bound to matched and mismatched DNA targets using a magnetic tweezers assay. Significant differences in complex stabilities were observed consistent with the presence of at least two distinct conformations. Surprisingly, in vivo analysis demonstrated that all mismatched targets stimulated robust primed adaptation irrespective of conformational states observed in vitro. Our results suggest that primed adaptation is a direct consequence of a reduced interference efficiency and/or rate and is not a consequence of distinct effector complex conformations on target DNA.
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Affiliation(s)
- Andrey Krivoy
- Center for Data-Intensive Biomedicine and Biotechnology, Skolkovo Institute of Science and Technology, Moscow 143028, Russia.,Molecular Biophysics Group, Peter Debye Institute for Soft Matter Physics, Universität Leipzig, Leipzig 04103, Germany
| | - Marius Rutkauskas
- Molecular Biophysics Group, Peter Debye Institute for Soft Matter Physics, Universität Leipzig, Leipzig 04103, Germany
| | - Konstantin Kuznedelov
- Waksman Institute, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA
| | - Olga Musharova
- Center for Data-Intensive Biomedicine and Biotechnology, Skolkovo Institute of Science and Technology, Moscow 143028, Russia.,Institute of Molecular Genetics, Russian Academy of Sciences, Moscow 123182, Russia
| | - Christophe Rouillon
- Molecular Biophysics Group, Peter Debye Institute for Soft Matter Physics, Universität Leipzig, Leipzig 04103, Germany
| | - Konstantin Severinov
- Center for Data-Intensive Biomedicine and Biotechnology, Skolkovo Institute of Science and Technology, Moscow 143028, Russia.,Waksman Institute, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA.,Institute of Molecular Genetics, Russian Academy of Sciences, Moscow 123182, Russia
| | - Ralf Seidel
- Molecular Biophysics Group, Peter Debye Institute for Soft Matter Physics, Universität Leipzig, Leipzig 04103, Germany
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22
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Ahmad I, Kulkarni M, Gopinath A, Saikrishnan K. Single-site DNA cleavage by Type III restriction endonuclease requires a site-bound enzyme and a trans-acting enzyme that are ATPase-activated. Nucleic Acids Res 2019; 46:6229-6237. [PMID: 29846668 PMCID: PMC6158743 DOI: 10.1093/nar/gky344] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 04/26/2018] [Indexed: 12/19/2022] Open
Abstract
Endonucleolytic cleavage of DNA by Type III restriction-modification (RM) enzymes requires long-range communication between at least two recognition sites in inverted orientation. This results in convergence of two nuclease domains, one each from the enzymes loaded at the recognition sites with one still bound to the site. The nucleases catalyze scission of the single-strands leading to double-strand DNA break. An obscure feature of the Type III RM enzymes EcoP1I and EcoP15I is their ability to cleave DNA having a single recognition site under certain conditions. Here we demonstrate that single-site cleavage is the result of cooperation between an enzyme bound to the recognition site in cis and one in trans. DNA cleavage is catalyzed by converging nucleases that are activated by hydrolysis-competent ATPase in presence of their respective DNA substrates. Furthermore, a single activated nuclease cannot nick a strand on its own, and requires the partner. Based on the commonalities in the features of single-site and two-site cleavage derived from this study, we propose that their mechanism is similar. Furthermore, the products of two-site cleavage can act as substrates and activators of single-site cleavage. The difference in the two modes lies in how the two cooperating enzymes converge, which in case of single-site cleavage appears to be via 3D diffusion.
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Affiliation(s)
- Ishtiyaq Ahmad
- Division of Biology, Indian Institute of Science Education and Research, Pune 411008, India
| | - Manasi Kulkarni
- Division of Biology, Indian Institute of Science Education and Research, Pune 411008, India
| | - Aathira Gopinath
- Division of Biology, Indian Institute of Science Education and Research, Pune 411008, India
| | - Kayarat Saikrishnan
- Division of Biology, Indian Institute of Science Education and Research, Pune 411008, India
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23
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Toliusis P, Tamulaitiene G, Grigaitis R, Tuminauskaite D, Silanskas A, Manakova E, Venclovas C, Szczelkun MD, Siksnys V, Zaremba M. The H-subunit of the restriction endonuclease CglI contains a prototype DEAD-Z1 helicase-like motor. Nucleic Acids Res 2019; 46:2560-2572. [PMID: 29471489 PMCID: PMC5861437 DOI: 10.1093/nar/gky107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 02/08/2018] [Indexed: 11/13/2022] Open
Abstract
CglI is a restriction endonuclease from Corynebacterium glutamicum that forms a complex between: two R-subunits that have site specific-recognition and nuclease domains; and two H-subunits, with Superfamily 2 helicase-like DEAD domains, and uncharacterized Z1 and C-terminal domains. ATP hydrolysis by the H-subunits catalyses dsDNA translocation that is necessary for long-range movement along DNA that activates nuclease activity. Here, we provide biochemical and molecular modelling evidence that shows that Z1 has a fold distantly-related to RecA, and that the DEAD-Z1 domains together form an ATP binding interface and are the prototype of a previously undescribed monomeric helicase-like motor. The DEAD-Z1 motor has unusual Walker A and Motif VI sequences those nonetheless have their expected functions. Additionally, it contains DEAD-Z1-specific features: an H/H motif and a loop (aa 163–aa 172), that both play a role in the coupling of ATP hydrolysis to DNA cleavage. We also solved the crystal structure of the C-terminal domain which has a unique fold, and demonstrate that the Z1-C domains are the principal DNA binding interface of the H-subunit. Finally, we use small angle X-ray scattering to provide a model for how the H-subunit domains are arranged in a dimeric complex.
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Affiliation(s)
- Paulius Toliusis
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Sauletekio al. 7, LT-10257 Vilnius, Lithuania
| | - Giedre Tamulaitiene
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Sauletekio al. 7, LT-10257 Vilnius, Lithuania
| | - Rokas Grigaitis
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Sauletekio al. 7, LT-10257 Vilnius, Lithuania
| | - Donata Tuminauskaite
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Sauletekio al. 7, LT-10257 Vilnius, Lithuania
| | - Arunas Silanskas
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Sauletekio al. 7, LT-10257 Vilnius, Lithuania
| | - Elena Manakova
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Sauletekio al. 7, LT-10257 Vilnius, Lithuania
| | - Ceslovas Venclovas
- Institute of Biotechnology, Life Sciences Center, 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
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Sauletekio al. 7, LT-10257 Vilnius, Lithuania
| | - Mindaugas Zaremba
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Sauletekio al. 7, LT-10257 Vilnius, Lithuania
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24
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Xiong L, Liu S, Chen S, Xiao Y, Zhu B, Gao Y, Zhang Y, Chen B, Luo J, Deng Z, Chen X, Wang L, Chen S. A new type of DNA phosphorothioation-based antiviral system in archaea. Nat Commun 2019; 10:1688. [PMID: 30975999 PMCID: PMC6459918 DOI: 10.1038/s41467-019-09390-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 03/07/2019] [Indexed: 01/21/2023] Open
Abstract
Archaea and Bacteria have evolved different defence strategies that target virtually all steps of the viral life cycle. The diversified virion morphotypes and genome contents of archaeal viruses result in a highly complex array of archaea-virus interactions. However, our understanding of archaeal antiviral activities lags far behind our knowledges of those in bacteria. Here we report a new archaeal defence system that involves DndCDEA-specific DNA phosphorothioate (PT) modification and the PbeABCD-mediated halt of virus propagation via inhibition of DNA replication. In contrast to the breakage of invasive DNA by DndFGH in bacteria, DndCDEA-PbeABCD does not degrade or cleave viral DNA. The PbeABCD-mediated PT defence system is widespread and exhibits extensive interdomain and intradomain gene transfer events. Our results suggest that DndCDEA-PbeABCD is a new type of PT-based virus resistance system, expanding the known arsenal of defence systems as well as our understanding of host-virus interactions.
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Affiliation(s)
- Lei Xiong
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, 430071, Wuhan, China
- Taihe Hospital, Hubei University of Medicine, 442000, Shiyan, Hubei, China
- Brain Center, Zhongnan Hospital, Wuhan University, 430071, Wuhan, China
| | - Siyi Liu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, 430071, Wuhan, China
- Brain Center, Zhongnan Hospital, Wuhan University, 430071, Wuhan, China
| | - Si Chen
- School of Biology and Pharmaceutical Engineering, Wuhan Polytechnic University, 430023, Wuhan, China
| | - Yao Xiao
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, 430071, Wuhan, China
- Brain Center, Zhongnan Hospital, Wuhan University, 430071, Wuhan, China
| | - Bochen Zhu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, 430071, Wuhan, China
- Brain Center, Zhongnan Hospital, Wuhan University, 430071, Wuhan, China
| | - Yali Gao
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, 430071, Wuhan, China
- Brain Center, Zhongnan Hospital, Wuhan University, 430071, Wuhan, China
| | - Yujing Zhang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, 430071, Wuhan, China
- Brain Center, Zhongnan Hospital, Wuhan University, 430071, Wuhan, China
| | - Beibei Chen
- College of Life Sciences, Wuhan University, 430071, Wuhan, China
| | - Jie Luo
- Taihe Hospital, Hubei University of Medicine, 442000, Shiyan, Hubei, China
| | - Zixin Deng
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, 430071, Wuhan, China
| | - Xiangdong Chen
- College of Life Sciences, Wuhan University, 430071, Wuhan, China
| | - Lianrong Wang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, 430071, Wuhan, China
- Taihe Hospital, Hubei University of Medicine, 442000, Shiyan, Hubei, China
- Brain Center, Zhongnan Hospital, Wuhan University, 430071, Wuhan, China
| | - Shi Chen
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, 430071, Wuhan, China.
- Taihe Hospital, Hubei University of Medicine, 442000, Shiyan, Hubei, China.
- Brain Center, Zhongnan Hospital, Wuhan University, 430071, Wuhan, China.
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25
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Breaking the speed limit with multimode fast scanning of DNA by Endonuclease V. Nat Commun 2018; 9:5381. [PMID: 30568191 PMCID: PMC6300609 DOI: 10.1038/s41467-018-07797-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 11/27/2018] [Indexed: 01/04/2023] Open
Abstract
In order to preserve genomic stability, cells rely on various repair pathways for removing DNA damage. The mechanisms how enzymes scan DNA and recognize their target sites are incompletely understood. Here, by using high-localization precision microscopy along with 133 Hz high sampling rate, we have recorded EndoV and OGG1 interacting with 12-kbp elongated λ-DNA in an optical trap. EndoV switches between three distinct scanning modes, each with a clear range of activation energy barriers. These results concur with average diffusion rate and occupancy of states determined by a hidden Markov model, allowing us to infer that EndoV confinement occurs when the intercalating wedge motif is involved in rigorous probing of the DNA, while highly mobile EndoV may disengage from a strictly 1D helical diffusion mode and hop along the DNA. This makes EndoV the first example of a monomeric, single-conformation and single-binding-site protein demonstrating the ability to switch between three scanning modes. How DNA repair proteins locate their target sites on DNA is still a matter of debate. Here the authors characterize by single-molecule fluorescence imaging the modes of scanning adopted by bacterial endonuclease V as it moves along linear DNA tracks.
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26
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Fabian R, Tyson C, Tuma PL, Pegg I, Sarkar A. A Horizontal Magnetic Tweezers and Its Use for Studying Single DNA Molecules. MICROMACHINES 2018; 9:mi9040188. [PMID: 30424121 PMCID: PMC6187538 DOI: 10.3390/mi9040188] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 04/11/2018] [Accepted: 04/12/2018] [Indexed: 11/29/2022]
Abstract
We report the development of a magnetic tweezers that can be used to micromanipulate single DNA molecules by applying picoNewton (pN)-scale forces in the horizontal plane. The resulting force–extension data from our experiments show high-resolution detection of changes in the DNA tether’s extension: ~0.5 pN in the force and <10 nm change in extension. We calibrate our instrument using multiple orthogonal techniques including the well-characterized DNA overstretching transition. We also quantify the repeatability of force and extension measurements, and present data on the behavior of the overstretching transition under varying salt conditions. The design and experimental protocols are described in detail, which should enable straightforward reproduction of the tweezers.
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Affiliation(s)
- Roberto Fabian
- Department of Physics and Vitreous State Laboratory, The Catholic University of America, Washington, DC 20064, USA.
| | - Christopher Tyson
- Biomedical Engineering Department and Vitreous State Laboratory, The Catholic University of America, Washington, DC 20064, USA.
| | - Pamela L Tuma
- Department of Biology, The Catholic University of America, Washington, DC 20064, USA.
| | - Ian Pegg
- Department of Physics and Vitreous State Laboratory, The Catholic University of America, Washington, DC 20064, USA.
| | - Abhijit Sarkar
- Department of Physics and Vitreous State Laboratory, The Catholic University of America, Washington, DC 20064, USA.
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27
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Madariaga-Marcos J, Hormeño S, Pastrana CL, Fisher GLM, Dillingham MS, Moreno-Herrero F. Force determination in lateral magnetic tweezers combined with TIRF microscopy. NANOSCALE 2018; 10:4579-4590. [PMID: 29461549 PMCID: PMC5831119 DOI: 10.1039/c7nr07344e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 12/07/2017] [Indexed: 06/08/2023]
Abstract
Combining single-molecule techniques with fluorescence microscopy has attracted much interest because it allows the correlation of mechanical measurements with directly visualized DNA : protein interactions. In particular, its combination with total internal reflection fluorescence microscopy (TIRF) is advantageous because of the high signal-to-noise ratio this technique achieves. This, however, requires stretching long DNA molecules across the surface of a flow cell to maximize polymer exposure to the excitation light. In this work, we develop a module to laterally stretch DNA molecules at a constant force, which can be easily implemented in regular or combined magnetic tweezers (MT)-TIRF setups. The pulling module is further characterized in standard flow cells of different thicknesses and glass capillaries, using two types of micrometer size superparamagnetic beads, long DNA molecules, and a home-built device to rotate capillaries with mrad precision. The force range achieved by the magnetic pulling module was between 0.1 and 30 pN. A formalism for estimating forces in flow-stretched tethered beads is also proposed, and the results compared with those of lateral MT, demonstrating that lateral MT achieve higher forces with lower dispersion. Finally, we show the compatibility with TIRF microscopy and the parallelization of measurements by characterizing DNA binding by the centromere-binding protein ParB from Bacillus subtilis. Simultaneous MT pulling and fluorescence imaging demonstrate the non-specific binding of BsParB on DNA under conditions restrictive to condensation.
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Affiliation(s)
- J. Madariaga-Marcos
- Department of Macromolecular Structures , Centro Nacional de Biotecnología , Consejo Superior de Investigaciones Científicas , 28049 Cantoblanco , Madrid , Spain .
| | - S. Hormeño
- Department of Macromolecular Structures , Centro Nacional de Biotecnología , Consejo Superior de Investigaciones Científicas , 28049 Cantoblanco , Madrid , Spain .
| | - C. L. Pastrana
- Department of Macromolecular Structures , Centro Nacional de Biotecnología , Consejo Superior de Investigaciones Científicas , 28049 Cantoblanco , Madrid , Spain .
| | - G. L. M. Fisher
- DNA:Protein Interactions Unit , School of Biochemistry , Biomedical Sciences Building , University of Bristol , Bristol , BS8 1TD , UK
| | - M. S. Dillingham
- DNA:Protein Interactions Unit , School of Biochemistry , Biomedical Sciences Building , University of Bristol , Bristol , BS8 1TD , UK
| | - F. Moreno-Herrero
- Department of Macromolecular Structures , Centro Nacional de Biotecnología , Consejo Superior de Investigaciones Científicas , 28049 Cantoblanco , Madrid , Spain .
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28
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Hudaiberdiev S, Shmakov S, Wolf YI, Terns MP, Makarova KS, Koonin EV. Phylogenomics of Cas4 family nucleases. BMC Evol Biol 2017; 17:232. [PMID: 29179671 PMCID: PMC5704561 DOI: 10.1186/s12862-017-1081-1] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 11/16/2017] [Indexed: 12/31/2022] Open
Abstract
Background The Cas4 family endonuclease is a component of the adaptation module in many variants of CRISPR-Cas adaptive immunity systems. Unlike most of the other Cas proteins, Cas4 is often encoded outside CRISPR-cas loci (solo-Cas4) and is also found in mobile genetic elements (MGE-Cas4). Results As part of our ongoing investigation of CRISPR-Cas evolution, we explored the phylogenomics of the Cas4 family. About 90% of the archaeal genomes encode Cas4 compared to only about 20% of the bacterial genomes. Many archaea encode both the CRISPR-associated form (CAS-Cas4) and solo-Cas4, whereas in bacteria, this combination is extremely rare. The solo-cas4 genes are over-represented in environmental bacteria and archaea with small genomes that typically lack CRISPR-Cas, suggesting that Cas4 could perform uncharacterized defense or repair functions in these microbes. Phylogenomic analysis indicates that both the CRISPR-associated cas4 genes are often transferred horizontally but almost exclusively, as part of the adaptation module. The evolutionary integrity of the adaptation module sharply contrasts the rampant shuffling of CRISPR-cas modules whereby a given variant of the adaptation module can combine with virtually any effector module. The solo-cas4 genes evolve primarily via vertical inheritance and are subject only to occasional horizontal transfer. The selection pressure on cas4 genes does not substantially differ between CAS-Cas4 and solo-cas4, and is close to the genomic median. Thus, cas4 genes, similarly to cas1 and cas2, evolve similarly to ‘regular’ microbial genes involved in various cellular functions, showing no evidence of direct involvement in virus-host arms races. A notable feature of the Cas4 family evolution is the frequent recruitment of cas4 genes by various mobile genetic elements (MGE), particularly, archaeal viruses. The functions of Cas4 in these elements are unknown and potentially might involve anti-defense roles. Conclusions Unlike most of the other Cas proteins, Cas4 family members are as often encoded by stand-alone genes as they are incorporated in CRISPR-Cas systems. In addition, cas4 genes were repeatedly recruited by MGE, perhaps, for anti-defense functions. Experimental characterization of the solo and MGE-encoded Cas4 nucleases is expected to reveal currently uncharacterized defense and anti-defense systems and their interactions with CRISPR-Cas systems. Electronic supplementary material The online version of this article (10.1186/s12862-017-1081-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sanjarbek Hudaiberdiev
- National Center for Biotechnology Information, National Institutes of Health, Bethesda, MD, USA
| | - Sergey Shmakov
- National Center for Biotechnology Information, National Institutes of Health, Bethesda, MD, USA.,Skolkovo Institute of Science and Technology, Skolkovo, 143025, Russia
| | - Yuri I Wolf
- National Center for Biotechnology Information, National Institutes of Health, Bethesda, MD, USA
| | - Michael P Terns
- Departments of Biochemistry and Molecular Biology, Genetics, and Microbiology, University of Georgia, Athens, GA, USA
| | - Kira S Makarova
- National Center for Biotechnology Information, National Institutes of Health, Bethesda, MD, USA
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Institutes of Health, Bethesda, MD, USA.
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29
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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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30
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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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31
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El Najjar N, Kaimer C, Rösch T, Graumann PL. Requirements for Septal Localization and Chromosome Segregation Activity of the DNA Translocase SftA from Bacillus subtilis. J Mol Microbiol Biotechnol 2017; 27:29-42. [PMID: 28110333 DOI: 10.1159/000450725] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 09/09/2016] [Indexed: 11/19/2022] Open
Abstract
Bacillus subtilis possesses 2 DNA translocases that affect late stages of chromosome segregation: SftA separates nonsegregated DNA prior to septum closure, while SpoIIIE rescues septum-entrapped DNA. We provide evidence that SftA is associated with the division machinery via a stretch of 47 amino acids within its N-terminus, suggesting that SftA is recruited by protein-protein interactions with a component of the division machinery. SftA was also recruited to mid-cell in the absence of its first 20 amino acids, which are proposed to contain a membrane-binding motif. Cell fractionation experiments showed that SftA can be found in the cytosolic fraction, and to a minor degree in the membrane fraction, showing that it is a soluble protein in vivo. The expression of truncated SftA constructs led to a dominant sftA deletion phenotype, even at very low induction rates of the truncated proteins, indicating that the incorporation of nonfunctional monomers into SftA hexamers abolishes functionality. Mobility shift experiments and surface plasmon binding studies showed that SftA binds to DNA in a cooperative manner, and demonstrated low ATPase activity when binding to short nucleotides rather than to long stretches of DNA.
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Affiliation(s)
- Nina El Najjar
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, and Department of Chemistry, Philipps-Universität Marburg, Marburg, Germany
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32
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Greene EC. On the influence of protein-DNA register during homologous recombination. Cell Cycle 2016; 15:172-5. [PMID: 26652653 DOI: 10.1080/15384101.2015.1121352] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Homologous recombination enables the exchange of genetic information between related DNA molecules and is a driving force in evolution. Using single-molecule optical microscopy we have recently shown that members of the Rad51/RecA family of recombinases stabilize paired homologous strand of DNA in precise 3-nt increments. Here we discuss an interesting conceptual implication of these results, which is that the recombinases may actively sense and reorganize their alignment register relative to the bound DNA sequences to ensure optimal base triplet pairing interactions during the early stages of recombination.
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Affiliation(s)
- Eric C Greene
- a Department of Biochemistry & Molecular Biophysics , Columbia University , New York , NY , USA
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33
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Dulin D, Cui TJ, Cnossen J, Docter MW, Lipfert J, Dekker NH. High Spatiotemporal-Resolution Magnetic Tweezers: Calibration and Applications for DNA Dynamics. Biophys J 2016; 109:2113-25. [PMID: 26588570 DOI: 10.1016/j.bpj.2015.10.018] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 10/05/2015] [Accepted: 10/13/2015] [Indexed: 11/16/2022] Open
Abstract
The observation of biological processes at the molecular scale in real time requires high spatial and temporal resolution. Magnetic tweezers are straightforward to implement, free of radiation or photodamage, and provide ample multiplexing capability, but their spatiotemporal resolution has lagged behind that of other single-molecule manipulation techniques, notably optical tweezers and AFM. Here, we present, to our knowledge, a new high-resolution magnetic tweezers apparatus. We systematically characterize the achievable spatiotemporal resolution for both incoherent and coherent light sources, different types and sizes of beads, and different types and lengths of tethered molecules. Using a bright coherent laser source for illumination and tracking at 6 kHz, we resolve 3 Å steps with a 1 s period for surface-melted beads and 5 Å steps with a 0.5 s period for double-stranded-dsDNA-tethered beads, in good agreement with a model of stochastic bead motion in the magnetic tweezers. We demonstrate how this instrument can be used to monitor the opening and closing of a DNA hairpin on millisecond timescales in real time, together with attendant changes in the hairpin dynamics upon the addition of deoxythymidine triphosphate. Our approach opens up the possibility of observing biological events at submillisecond timescales with subnanometer resolution using camera-based detection.
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Affiliation(s)
- David Dulin
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands.
| | - Tao Ju Cui
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Jelmer Cnossen
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Margreet W Docter
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Jan Lipfert
- Department of Physics, Nanosystems Initiative Munich and Center for Nanoscience, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Nynke H Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands.
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34
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TALE proteins search DNA using a rotationally decoupled mechanism. Nat Chem Biol 2016; 12:831-7. [DOI: 10.1038/nchembio.2152] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 05/27/2016] [Indexed: 12/27/2022]
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35
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Hodeib S, Raj S, Manosas M, Zhang W, Bagchi D, Ducos B, Allemand JF, Bensimon D, Croquette V. Single molecule studies of helicases with magnetic tweezers. Methods 2016; 105:3-15. [DOI: 10.1016/j.ymeth.2016.06.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 05/31/2016] [Accepted: 06/20/2016] [Indexed: 10/21/2022] Open
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36
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Kemmerich FE, Kasaciunaite K, Seidel R. Modular magnetic tweezers for single-molecule characterizations of helicases. Methods 2016; 108:4-13. [PMID: 27402355 DOI: 10.1016/j.ymeth.2016.07.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 07/05/2016] [Accepted: 07/06/2016] [Indexed: 01/09/2023] Open
Abstract
Magnetic tweezers provide a versatile toolkit supporting the mechanistic investigation of helicases. In the present article, we show that custom magnetic tweezers setups are straightforward to construct and can easily be extended to provide adaptable platforms, capable of addressing a multitude of enquiries regarding the functions of these fascinating molecular machines. We first address the fundamental components of a basic magnetic tweezers scheme and review some previous results to demonstrate the versatility of this instrument. We then elaborate on several extensions to the basic magnetic tweezers scheme, and demonstrate their applications with data from ongoing research. As our methodological overview illustrates, magnetic tweezers are an extremely useful tool for the characterization of helicases and a custom built instrument can be specifically tailored to suit the experimenter's needs.
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Affiliation(s)
- Felix E Kemmerich
- Molecular Biophysics Group, Institute of Experimental Physics I, Universität Leipzig, 04103 Leipzig, Germany
| | - Kristina Kasaciunaite
- Molecular Biophysics Group, Institute of Experimental Physics I, Universität Leipzig, 04103 Leipzig, Germany
| | - Ralf Seidel
- Molecular Biophysics Group, Institute of Experimental Physics I, Universität Leipzig, 04103 Leipzig, Germany.
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37
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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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38
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Kemmerich FE, Swoboda M, Kauert DJ, Grieb MS, Hahn S, Schwarz FW, Seidel R, Schlierf M. Simultaneous Single-Molecule Force and Fluorescence Sampling of DNA Nanostructure Conformations Using Magnetic Tweezers. NANO LETTERS 2016; 16:381-6. [PMID: 26632021 DOI: 10.1021/acs.nanolett.5b03956] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
We present a hybrid single-molecule technique combining magnetic tweezers and Förster resonance energy transfer (FRET) measurements. Through applying external forces to a paramagnetic sphere, we induce conformational changes in DNA nanostructures, which are detected in two output channels simultaneously. First, by tracking a magnetic bead with high spatial and temporal resolution, we observe overall DNA length changes along the force axis. Second, the measured FRET efficiency between two fluorescent probes monitors local conformational changes. The synchronized orthogonal readout in different observation channels will facilitate deciphering the complex mechanisms of biomolecular machines.
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Affiliation(s)
- Felix E Kemmerich
- Institute for Molecular Cell Biology, University of Münster , 48149 Münster, Germany
- Institute of Experimental Physics I, Universität Leipzig , 04103 Leipzig, Germany
| | - Marko Swoboda
- B CUBE - Center for Molecular Bioengineering, TU Dresden , 01307 Dresden, Germany
| | - Dominik J Kauert
- Institute for Molecular Cell Biology, University of Münster , 48149 Münster, Germany
- Institute of Experimental Physics I, Universität Leipzig , 04103 Leipzig, Germany
| | - M Svea Grieb
- B CUBE - Center for Molecular Bioengineering, TU Dresden , 01307 Dresden, Germany
| | - Steffen Hahn
- B CUBE - Center for Molecular Bioengineering, TU Dresden , 01307 Dresden, Germany
| | - Friedrich W Schwarz
- B CUBE - Center for Molecular Bioengineering, TU Dresden , 01307 Dresden, Germany
- cfaed - Center for Advancing Electronics Dresden, TU Dresden , 01307 Dresden, Germany
| | - Ralf Seidel
- Institute for Molecular Cell Biology, University of Münster , 48149 Münster, Germany
- Institute of Experimental Physics I, Universität Leipzig , 04103 Leipzig, Germany
| | - Michael Schlierf
- B CUBE - Center for Molecular Bioengineering, TU Dresden , 01307 Dresden, Germany
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39
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Transverse Magnetic Tweezers Allowing Coincident Epifluorescence Microscopy on Horizontally Extended DNA. Methods Mol Biol 2016; 1431:73-90. [PMID: 27283303 DOI: 10.1007/978-1-4939-3631-1_7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Longitudinal magnetic tweezers (L-MT) have seen wide-scale adoption as the tool-of-choice for stretching and twisting a single DNA molecule. They are also used to probe topological changes in DNA as a result of protein binding and enzymatic activity. However, in the longitudinal configuration, the DNA molecule is extended perpendicular to the imaging plane. As a result, it is only possible to infer biological activity from the motion of the tethered superparamagnetic microsphere. Described here is a "transverse" magnetic tweezers (T-MT) geometry featuring simultaneous control of DNA extension and spatially coincident video-rate epifluorescence imaging. Unlike in L-MT, DNA tethers in T-MT are extended parallel to the imaging plane between two micron-sized spheres, and importantly protein targets on the DNA can be localized using fluorescent nanoparticles. The T-MT can manipulate a long DNA construct at molecular extensions approaching the contour length defined by B-DNA helical geometry, and the measured entropic elasticity agrees with the worm-like chain model (force < 35 pN). By incorporating a torsionally constrained DNA tether, the T-MT would allow both the relative extension and twist of the tether to be manipulated, while viewing far-red emitting fluorophore-labeled targets. This T-MT design has the potential to enable the study of DNA binding and remodeling processes under conditions of constant force and defined torsional stress.
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40
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Simple horizontal magnetic tweezers for micromanipulation of single DNA molecules and DNA-protein complexes. Biotechniques 2016; 60:21-7. [PMID: 26757808 DOI: 10.2144/000114369] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 09/08/2015] [Indexed: 12/16/2022] Open
Abstract
We report the development of a simple-to-implement magnetic force transducer that can apply a wide range of piconewton (pN) scale forces on single DNA molecules and DNA-protein complexes in the horizontal plane. The resulting low-noise force-extension data enable very high-resolution detection of changes in the DNA tether's extension: ~0.05 pN in force and <10 nm change in extension. We have also verified that we can manipulate DNA in near equilibrium conditions through the wide range of forces by ramping the force from low to high and back again, and observing minimal hysteresis in the molecule's force response. Using a calibration technique based on Stokes' drag law, we have confirmed our force measurements from DNA force-extension experiments obtained using the fluctuation-dissipation theorem applied to transverse fluctuations of the magnetic microsphere. We present data on the force-distance characteristics of a DNA molecule complexed with histones. The results illustrate how the tweezers can be used to study DNA binding proteins at the single molecule level.
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41
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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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42
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Chand MK, Nirwan N, Diffin FM, van Aelst K, Kulkarni M, Pernstich C, Szczelkun MD, Saikrishnan K. Translocation-coupled DNA cleavage by the Type ISP restriction-modification enzymes. Nat Chem Biol 2015; 11:870-7. [PMID: 26389736 PMCID: PMC4636054 DOI: 10.1038/nchembio.1926] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 08/27/2015] [Indexed: 01/21/2023]
Abstract
Production of endonucleolytic double-strand DNA breaks requires separate strand cleavage events. Although catalytic mechanisms for simple, dimeric endonucleases are known, there are many complex nuclease machines that are poorly understood. Here we studied the single polypeptide Type ISP restriction-modification (RM) enzymes, which cleave random DNA between distant target sites when two enzymes collide after convergent ATP-driven translocation. We report the 2.7-Å resolution X-ray crystal structure of a Type ISP enzyme-DNA complex, revealing that both the helicase-like ATPase and nuclease are located upstream of the direction of translocation, an observation inconsistent with simple nuclease-domain dimerization. Using single-molecule and biochemical techniques, we demonstrate that each ATPase remodels its DNA-protein complex and translocates along DNA without looping it, leading to a collision complex in which the nuclease domains are distal. Sequencing of the products of single cleavage events suggests a previously undescribed endonuclease model, where multiple, stochastic strand-nicking events combine to produce DNA scission.
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Affiliation(s)
- Mahesh Kumar Chand
- Division of Biology, Indian Institute of Science Education and Research, Pune, 411008, India
| | - Neha Nirwan
- Division of Biology, Indian Institute of Science Education and Research, Pune, 411008, India
| | - Fiona M. Diffin
- DNA-Protein Interactions Unit, School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Kara van Aelst
- DNA-Protein Interactions Unit, School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Manasi Kulkarni
- Division of Biology, Indian Institute of Science Education and Research, Pune, 411008, India
| | - Christian Pernstich
- DNA-Protein Interactions Unit, School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Mark D. Szczelkun
- DNA-Protein Interactions Unit, School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Kayarat Saikrishnan
- Division of Biology, Indian Institute of Science Education and Research, Pune, 411008, India
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43
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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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44
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A dynamic DNA-repair complex observed by correlative single-molecule nanomanipulation and fluorescence. Nat Struct Mol Biol 2015; 22:452-7. [PMID: 25961799 DOI: 10.1038/nsmb.3019] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 04/03/2015] [Indexed: 01/20/2023]
Abstract
We characterize in real time the composition and catalytic state of the initial Escherichia coli transcription-coupled repair (TCR) machinery by using correlative single-molecule methods. TCR initiates when RNA polymerase (RNAP) stalled by a lesion is displaced by the Mfd DNA translocase, thus giving repair components access to the damage. We previously used DNA nanomanipulation to obtain a nanomechanical readout of protein-DNA interactions during TCR initiation. Here we correlate this signal with simultaneous single-molecule fluorescence imaging of labeled components (RNAP, Mfd or RNA) to monitor the composition and localization of the complex. Displacement of stalled RNAP by Mfd results in loss of nascent RNA but not of RNAP, which remains associated with Mfd as a long-lived complex on the DNA. This complex translocates at ∼4 bp/s along the DNA, in a manner determined by the orientation of the stalled RNAP on the DNA.
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45
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Directional R-Loop Formation by the CRISPR-Cas Surveillance Complex Cascade Provides Efficient Off-Target Site Rejection. Cell Rep 2015; 10:1534-1543. [PMID: 25753419 DOI: 10.1016/j.celrep.2015.01.067] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 01/09/2015] [Accepted: 01/28/2015] [Indexed: 11/21/2022] Open
Abstract
CRISPR-Cas systems provide bacteria and archaea with adaptive immunity against foreign nucleic acids. In type I CRISPR-Cas systems, invading DNA is detected by a large ribonucleoprotein surveillance complex called Cascade. The crRNA component of Cascade is used to recognize target sites in foreign DNA (protospacers) by formation of an R-loop driven by base-pairing complementarity. Using single-molecule supercoiling experiments with near base-pair resolution, we probe here the mechanism of R-loop formation and detect short-lived R-loop intermediates on off-target sites bearing single mismatches. We show that R-loops propagate directionally starting from the protospacer-adjacent motif (PAM). Upon reaching a mismatch, R-loop propagation stalls and collapses in a length-dependent manner. This unambiguously demonstrates that directional zipping of the R-loop accomplishes efficient target recognition by rapidly rejecting binding to off-target sites with PAM-proximal mutations. R-loops that reach the protospacer end become locked to license DNA degradation by the auxiliary Cas3 nuclease/helicase without further target verification.
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46
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Camera-based three-dimensional real-time particle tracking at kHz rates and Ångström accuracy. Nat Commun 2015; 6:5885. [PMID: 25565216 PMCID: PMC4338538 DOI: 10.1038/ncomms6885] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 11/18/2014] [Indexed: 01/30/2023] Open
Abstract
Optical and magnetic tweezers are widely employed to probe the mechanics and activity of individual biomolecular complexes. They rely on micrometer-sized particles to detect molecular conformational changes from the particle position. Real-time particle tracking with Ångström accuracy has so far been only achieved using laser detection through photodiodes. Here we demonstrate that camera-based imaging can provide a similar performance for all three dimensions. Particle imaging at kHz rates is combined with real-time data processing being accelerated by a graphics processing unit. For particles that are fixed in the sample cell we can detect 3 Å sized steps that are introduced by cell translations at rates of 10 Hz, while for DNA-tethered particles 5 Å steps at 1 Hz can be resolved. Moreover, 20 particles can be tracked in parallel with comparable accuracy. Our approach provides a simple and robust way for high-resolution tweezers experiments using multiple particles at a time.
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47
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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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48
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Hohng S, Lee S, Lee J, Jo MH. Maximizing information content of single-molecule FRET experiments: multi-color FRET and FRET combined with force or torque. Chem Soc Rev 2014; 43:1007-13. [PMID: 23970315 DOI: 10.1039/c3cs60184f] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Since its first demonstration about twenty years ago, single-molecule fluorescence resonance energy transfer (FRET) has undergone remarkable technical advances. In this tutorial review, we will discuss two technical advances that increase the information content of the single-molecule FRET measurements: single-molecule multi-color FRET and single-molecule FRET combined with force or torque. Our expectations for future developments will be briefly discussed at the end.
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Affiliation(s)
- Sungchul Hohng
- Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea.
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49
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Nguyen B, Sokoloski J, Galletto R, Elson EL, Wold MS, Lohman TM. Diffusion of human replication protein A along single-stranded DNA. J Mol Biol 2014; 426:3246-3261. [PMID: 25058683 DOI: 10.1016/j.jmb.2014.07.014] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 06/30/2014] [Accepted: 07/08/2014] [Indexed: 10/25/2022]
Abstract
Replication protein A (RPA) is a eukaryotic single-stranded DNA (ssDNA) binding protein that plays critical roles in most aspects of genome maintenance, including replication, recombination and repair. RPA binds ssDNA with high affinity, destabilizes DNA secondary structure and facilitates binding of other proteins to ssDNA. However, RPA must be removed from or redistributed along ssDNA during these processes. To probe the dynamics of RPA-DNA interactions, we combined ensemble and single-molecule fluorescence approaches to examine human RPA (hRPA) diffusion along ssDNA and find that an hRPA heterotrimer can diffuse rapidly along ssDNA. Diffusion of hRPA is functional in that it provides the mechanism by which hRPA can transiently disrupt DNA hairpins by diffusing in from ssDNA regions adjacent to the DNA hairpin. hRPA diffusion was also monitored by the fluctuations in fluorescence intensity of a Cy3 fluorophore attached to the end of ssDNA. Using a novel method to calibrate the Cy3 fluorescence intensity as a function of hRPA position on the ssDNA, we estimate a one-dimensional diffusion coefficient of hRPA on ssDNA of D1~5000nt(2) s(-1) at 37°C. Diffusion of hRPA while bound to ssDNA enables it to be readily repositioned to allow other proteins access to ssDNA.
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Affiliation(s)
- Binh Nguyen
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Joshua Sokoloski
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Roberto Galletto
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Elliot L Elson
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Marc S Wold
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Timothy M Lohman
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO 63110, USA.
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50
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Szczelkun MD, Tikhomirova MS, Sinkunas T, Gasiunas G, Karvelis T, Pschera P, Siksnys V, Seidel R. Direct observation of R-loop formation by single RNA-guided Cas9 and Cascade effector complexes. Proc Natl Acad Sci U S A 2014; 111:9798-803. [PMID: 24912165 PMCID: PMC4103346 DOI: 10.1073/pnas.1402597111] [Citation(s) in RCA: 320] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Clustered, regularly interspaced, short palindromic repeats (CRISPR)/CRISPR-associated (Cas) systems protect bacteria and archaea from infection by viruses and plasmids. Central to this defense is a ribonucleoprotein complex that produces RNA-guided cleavage of foreign nucleic acids. In DNA-targeting CRISPR-Cas systems, the RNA component of the complex encodes target recognition by forming a site-specific hybrid (R-loop) with its complement (protospacer) on an invading DNA while displacing the noncomplementary strand. Subsequently, the R-loop structure triggers DNA degradation. Although these reactions have been reconstituted, the exact mechanism of R-loop formation has not been fully resolved. Here, we use single-molecule DNA supercoiling to directly observe and quantify the dynamics of torque-dependent R-loop formation and dissociation for both Cascade- and Cas9-based CRISPR-Cas systems. We find that the protospacer adjacent motif (PAM) affects primarily the R-loop association rates, whereas protospacer elements distal to the PAM affect primarily R-loop stability. Furthermore, Cascade has higher torque stability than Cas9 by using a conformational locking step. Our data provide direct evidence for directional R-loop formation, starting from PAM recognition and expanding toward the distal protospacer end. Moreover, we introduce DNA supercoiling as a quantitative tool to explore the sequence requirements and promiscuities of orthogonal CRISPR-Cas systems in rapidly emerging gene-targeting applications.
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Affiliation(s)
- Mark D Szczelkun
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom;
| | - Maria S Tikhomirova
- Institute for Molecular Cell Biology, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany;Biotechnology Center, Technische Universität Dresden, 01062 Dresden, Germany; and
| | - Tomas Sinkunas
- Department of Protein-Nucleic Acid Interactions, Institute of Biotechnology, Vilnius University, LT-02241 Vilnius, Lithuania
| | - Giedrius Gasiunas
- Department of Protein-Nucleic Acid Interactions, Institute of Biotechnology, Vilnius University, LT-02241 Vilnius, Lithuania
| | - Tautvydas Karvelis
- Department of Protein-Nucleic Acid Interactions, Institute of Biotechnology, Vilnius University, LT-02241 Vilnius, Lithuania
| | - Patrizia Pschera
- Biotechnology Center, Technische Universität Dresden, 01062 Dresden, Germany; and
| | - Virginijus Siksnys
- Department of Protein-Nucleic Acid Interactions, Institute of Biotechnology, Vilnius University, LT-02241 Vilnius, Lithuania
| | - Ralf Seidel
- Institute for Molecular Cell Biology, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany;Biotechnology Center, Technische Universität Dresden, 01062 Dresden, Germany; and
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