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Luo J, Chen H, An R, Liang X. Efficient preparation of AppDNA/AppRNA by T4 DNA ligase aided by a DNA involving mismatched mini-hairpin structure at its 3′ side. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2022. [DOI: 10.1246/bcsj.20220199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Jian Luo
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, P. R. China
| | - Hui Chen
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, P. R. China
| | - Ran An
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, P. R. China
- Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266235, P. R. China
| | - Xingguo Liang
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, P. R. China
- Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266235, P. R. China
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Molecular scaffolds: when DNA becomes the hardware for single-molecule investigations. Curr Opin Chem Biol 2019; 53:192-203. [DOI: 10.1016/j.cbpa.2019.09.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 09/21/2019] [Accepted: 09/24/2019] [Indexed: 01/14/2023]
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McCloskey CM, Liao JY, Bala S, Chaput JC. Ligase-Mediated Threose Nucleic Acid Synthesis on DNA Templates. ACS Synth Biol 2019; 8:282-286. [PMID: 30629885 DOI: 10.1021/acssynbio.8b00511] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ligases are a class of enzymes that catalyze the formation of phosphodiester bonds between an oligonucleotide donor with a 5' terminal phosphate and an oligonucleotide acceptor with a 3' terminal hydroxyl group. Here, we wished to explore the substrate specificity of naturally occurring DNA and RNA ligases to determine whether the molecular recognition of these enzymes is sufficiently general to synthesize alternative genetic polymers with backbone structures that are distinct from those found in nature. We chose threose nucleic acid (TNA) as a model system, as TNA is known to be biologically stable and capable of undergoing Darwinian evolution. Enzyme screening and reaction optimization identified several ligases that can recognize TNA as either the donor or acceptor strand with DNA. Less discrimination occurs on the acceptor strand indicating that the determinants of substrate specificity depend primarily on the composition of the donor strand. Remarkably, T3 and T7 ligases were able to join TNA homopolymers together, which is surprising given that the TNA backbone is one atom shorter than that of DNA. In this reaction, the base composition of the ligation junction strongly favors the formation of A-T and A-G linkages. We suggest that these results will enable the assembly of TNA oligonucleotides of lengths beyond what is currently possible by solid-phase synthesis and provide a starting point for further optimization by directed evolution.
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Lipfert J, van Oene MM, Lee M, Pedaci F, Dekker NH. Torque spectroscopy for the study of rotary motion in biological systems. Chem Rev 2014; 115:1449-74. [PMID: 25541648 DOI: 10.1021/cr500119k] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Jan Lipfert
- Department of Physics, Nanosystems Initiative Munich, and Center for NanoScience (CeNS), Ludwig-Maximilian-University Munich , Amalienstrasse 54, 80799 Munich, Germany
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Janissen R, Berghuis BA, Dulin D, Wink M, van Laar T, Dekker NH. Invincible DNA tethers: covalent DNA anchoring for enhanced temporal and force stability in magnetic tweezers experiments. Nucleic Acids Res 2014; 42:e137. [PMID: 25140010 PMCID: PMC4191378 DOI: 10.1093/nar/gku677] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Magnetic tweezers are a powerful single-molecule technique that allows real-time quantitative investigation of biomolecular processes under applied force. High pulling forces exceeding tens of picoNewtons may be required, e.g. to probe the force range of proteins that actively transcribe or package the genome. Frequently, however, the application of such forces decreases the sample lifetime, hindering data acquisition. To provide experimentally viable sample lifetimes in the face of high pulling forces, we have designed a novel anchoring strategy for DNA in magnetic tweezers. Our approach, which exploits covalent functionalization based on heterobifunctional poly(ethylene glycol) crosslinkers, allows us to strongly tether DNA while simultaneously suppressing undesirable non-specific adhesion. A complete force and lifetime characterization of these covalently anchored DNA-tethers demonstrates that, compared to more commonly employed anchoring strategies, they withstand 3-fold higher pulling forces (up to 150 pN) and exhibit up to 200-fold higher lifetimes (exceeding 24 h at a constant force of 150 pN). This advance makes it possible to apply the full range of biologically relevant force scales to biomolecular processes, and its straightforward implementation should extend its reach to a multitude of applications in the field of single-molecule force spectroscopy.
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Affiliation(s)
- Richard Janissen
- Department of Bionanoscience, Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Bojk A Berghuis
- Department of Bionanoscience, Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - David Dulin
- Department of Bionanoscience, Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Max Wink
- Department of Bionanoscience, Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Theo van Laar
- Department of Bionanoscience, Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Nynke H Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
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Lohman GJS, Chen L, Evans TC. Kinetic characterization of single strand break ligation in duplex DNA by T4 DNA ligase. J Biol Chem 2011; 286:44187-44196. [PMID: 22027837 PMCID: PMC3243518 DOI: 10.1074/jbc.m111.284992] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 10/14/2011] [Indexed: 01/24/2023] Open
Abstract
T4 DNA ligase catalyzes phosphodiester bond formation between juxtaposed 5'-phosphate and 3'-hydroxyl termini in duplex DNA in three steps: 1) enzyme-adenylylate formation by reaction with ATP; 2) adenylyl transfer to a 5'-phosphorylated polynucleotide to generate adenylylated DNA; and 3) phosphodiester bond formation with release of AMP. This investigation used synthetic, nicked DNA substrates possessing either a 5'-phosphate or a 5'-adenylyl phosphate. Steady state experiments with a nicked substrate containing juxtaposed dC and 5'-phosphorylated dT deoxynucleotides (substrate 1) yielded kcat and kcat/Km values of 0.4±0.1 s(-1) and 150±50 μm(-1) s(-1), respectively. Under identical reaction conditions, turnover of an adenylylated version of this substrate (substrate 1A) yielded kcat and kcat/Km values of 0.64±0.08 s(-1) and 240±40 μm(-1) s(-1). Single turnover experiments utilizing substrate 1 gave fits for the forward rates of Step 2 (k2) and Step 3 (k3) of 5.3 and 38 s(-1), respectively, with the slowest step ∼10-fold faster than the rate of turnover seen under steady state conditions. Single turnover experiments with substrate 1A produced a Step 3 forward rate constant of 4.3 s(-1), also faster than the turnover rate of 1A. Enzyme self-adenylylation was confirmed to also occur on a fast time scale (∼6 s(-1)), indicating that the rate-limiting step for T4 DNA ligase nick sealing is not a chemical step but rather is most likely product release. Pre-steady state reactions displayed a clear burst phase, consistent with this conclusion.
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Affiliation(s)
| | - Lixin Chen
- New England Biolabs Inc., Ipswich, Massachusetts 01938-2723
| | - Thomas C Evans
- New England Biolabs Inc., Ipswich, Massachusetts 01938-2723.
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Lipfert J, Kerssemakers JJW, Rojer M, Dekker NH. A method to track rotational motion for use in single-molecule biophysics. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:103707. [PMID: 22047303 DOI: 10.1063/1.3650461] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The double helical nature of DNA links many cellular processes such as DNA replication, transcription, and repair to rotational motion and the accumulation of torsional strain. Magnetic tweezers (MTs) are a single-molecule technique that enables the application of precisely calibrated stretching forces to nucleic acid tethers and to control their rotational motion. However, conventional magnetic tweezers do not directly monitor rotation or measure torque. Here, we describe a method to directly measure rotational motion of particles in MT. The method relies on attaching small, non-magnetic beads to the magnetic beads to act as fiducial markers for rotational tracking. CCD images of the beads are analyzed with a tracking algorithm specifically designed to minimize crosstalk between translational and rotational motion: first, the in-plane center position of the magnetic bead is determined with a kernel-based tracker, while subsequently the height and rotation angle of the bead are determined via correlation-based algorithms. Evaluation of the tracking algorithm using both simulated images and recorded images of surface-immobilized beads demonstrates a rotational resolution of 0.1°, while maintaining a translational resolution of 1-2 nm. Example traces of the rotational fluctuations exhibited by DNA-tethered beads confined in magnetic potentials of varying stiffness demonstrate the robustness of the method and the potential for simultaneous tracking of multiple beads. Our rotation tracking algorithm enables the extension of MTs to magnetic torque tweezers (MTT) to directly measure the torque in single molecules. In addition, we envision uses of the algorithm in a range of biophysical measurements, including further extensions of MT, tethered particle motion, and optical trapping measurements.
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Affiliation(s)
- Jan Lipfert
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
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Samai P, Shuman S. Structure-function analysis of the OB and latch domains of chlorella virus DNA ligase. J Biol Chem 2011; 286:22642-52. [PMID: 21527793 DOI: 10.1074/jbc.m111.245399] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Chlorella virus DNA ligase (ChVLig) is a minimized eukaryal ATP-dependent DNA sealing enzyme with an intrinsic nick-sensing function. ChVLig consists of three structural domains, nucleotidyltransferase (NTase), OB-fold, and latch, that envelop the nicked DNA as a C-shaped protein clamp. The OB domain engages the DNA minor groove on the face of the duplex behind the nick, and it makes contacts to amino acids in the NTase domain surrounding the ligase active site. The latch module occupies the DNA major groove flanking the nick. Residues at the tip of the latch contact the NTase domain to close the ligase clamp. Here we performed a structure-guided mutational analysis of the OB and latch domains. Alanine scanning defined seven individual amino acids as essential in vivo (Lys-274, Arg-285, Phe-286, and Val-288 in the OB domain; Asn-214, Phe-215, and Tyr-217 in the latch), after which structure-activity relations were clarified by conservative substitutions. Biochemical tests of the composite nick sealing reaction and of each of the three chemical steps of the ligation pathway highlighted the importance of Arg-285 and Phe-286 in the catalysis of the DNA adenylylation and phosphodiester synthesis reactions. Phe-286 interacts with the nick 5'-phosphate nucleotide and the 3'-OH base pair and distorts the DNA helical conformation at the nick. Arg-285 is a key component of the OB-NTase interface, where it forms a salt bridge to the essential Asp-29 side chain, which is imputed to coordinate divalent metal catalysts during the nick sealing steps.
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Affiliation(s)
- Poulami Samai
- Molecular Biology Program, Sloan-Kettering Institute, New York, New York 10065, USA
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Samai P, Shuman S. Functional dissection of the DNA interface of the nucleotidyltransferase domain of chlorella virus DNA ligase. J Biol Chem 2011; 286:13314-26. [PMID: 21335605 DOI: 10.1074/jbc.m111.226191] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Chlorella virus DNA ligase (ChVLig) has pluripotent biological activity and an intrinsic nick-sensing function. ChVLig consists of three structural modules that envelop nicked DNA as a C-shaped protein clamp: a nucleotidyltransferase (NTase) domain and an OB domain (these two are common to all DNA ligases) as well as a distinctive β-hairpin latch module. The NTase domain, which performs the chemical steps of ligation, binds the major groove flanking the nick and the minor groove on the 3'-OH side of the nick. Here we performed a structure-guided mutational analysis of the NTase domain, surveying the effects of 35 mutations in 19 residues on ChVLig activity in vivo and in vitro, including biochemical tests of the composite nick sealing reaction and of the three component steps of the ligation pathway (ligase adenylylation, DNA adenylylation, and phosphodiester synthesis). The results highlight (i) key contacts by Thr-84 and Lys-173 to the template DNA strand phosphates at the outer margins of the DNA ligase footprint; (ii) essential contacts of Ser-41, Arg-42, Met-83, and Phe-75 with the 3'-OH strand at the nick; (iii) Arg-176 phosphate contacts at the nick and with ATP during ligase adenylylation; (iv) the role of Phe-44 in forming the protein clamp around the nicked DNA substrate; and (v) the importance of adenine-binding residue Phe-98 in all three steps of ligation. Kinetic analysis of single-turnover nick sealing by ChVLig-AMP underscored the importance of Phe-75-mediated distortion of the nick 3'-OH nucleoside in the catalysis of DNA 5'-adenylylation (step 2) and phosphodiester synthesis (step 3). Induced fit of the nicked DNA into a distorted conformation when bound within the ligase clamp may account for the nick-sensing capacity of ChVLig.
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Affiliation(s)
- Poulami Samai
- Molecular Biology Program, Sloan-Kettering Institute, New York, New York 10065, USA
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te Velthuis AJW, Kerssemakers JWJ, Lipfert J, Dekker NH. Quantitative guidelines for force calibration through spectral analysis of magnetic tweezers data. Biophys J 2010; 99:1292-302. [PMID: 20713015 DOI: 10.1016/j.bpj.2010.06.008] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Revised: 06/01/2010] [Accepted: 06/03/2010] [Indexed: 11/24/2022] Open
Abstract
Single-molecule techniques are powerful tools that can be used to study the kinetics and mechanics of a variety of enzymes and their complexes. Force spectroscopy, for example, can be used to control the force applied to a single molecule and thereby facilitate the investigation of real-time nucleic acid-protein interactions. In magnetic tweezers, which offer straightforward control and compatibility with fluorescence measurements or parallel tracking modes, force-measurement typically relies on the analysis of positional fluctuations through video microscopy. Significant errors in force estimates, however, may arise from incorrect spectral analysis of the Brownian motion in the magnetic tweezers. Here we investigated physical and analytical optimization procedures that can be used to improve the range over which forces can be reliably measured. To systematically probe the limitations of magnetic tweezers spectral analysis, we have developed a magnetic tweezers simulator, whose outcome was validated with experimental data. Using this simulator, we evaluate methods to correctly perform force experiments and provide guidelines for correct force calibration under configurations that can be encountered in typical magnetic tweezers experiments.
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Affiliation(s)
- Aartjan J W te Velthuis
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
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Magnetic torque tweezers: measuring torsional stiffness in DNA and RecA-DNA filaments. Nat Methods 2010; 7:977-80. [PMID: 20953173 DOI: 10.1038/nmeth.1520] [Citation(s) in RCA: 200] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Accepted: 09/23/2010] [Indexed: 11/08/2022]
Abstract
We introduce magnetic torque tweezers, which enable direct single-molecule measurements of torque. Our measurements of the effective torsional stiffness C of dsDNA indicated a substantial force dependence, with C = approximately 40 nm at low forces up to C = approximately 100 nm at high forces. The initial torsional stiffness of RecA filaments was nearly twofold larger than that for dsDNA, yet at moderate torques further build-up of torsional strain was prevented.
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Lipfert J, Hao X, Dekker NH. Quantitative modeling and optimization of magnetic tweezers. Biophys J 2009; 96:5040-9. [PMID: 19527664 DOI: 10.1016/j.bpj.2009.03.055] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Revised: 03/13/2009] [Accepted: 03/17/2009] [Indexed: 10/20/2022] Open
Abstract
Magnetic tweezers are a powerful tool to manipulate single DNA or RNA molecules and to study nucleic acid-protein interactions in real time. Here, we have modeled the magnetic fields of permanent magnets in magnetic tweezers and computed the forces exerted on superparamagnetic beads from first principles. For simple, symmetric geometries the magnetic fields can be calculated semianalytically using the Biot-Savart law. For complicated geometries and in the presence of an iron yoke, we employ a finite-element three-dimensional PDE solver to numerically solve the magnetostatic problem. The theoretical predictions are in quantitative agreement with direct Hall-probe measurements of the magnetic field and with measurements of the force exerted on DNA-tethered beads. Using these predictive theories, we systematically explore the effects of magnet alignment, magnet spacing, magnet size, and of adding an iron yoke to the magnets on the forces that can be exerted on tethered particles. We find that the optimal configuration for maximal stretching forces is a vertically aligned pair of magnets, with a minimal gap between the magnets and minimal flow cell thickness. Following these principles, we present a configuration that allows one to apply > or = 40 pN stretching forces on approximately 1-microm tethered beads.
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Affiliation(s)
- Jan Lipfert
- Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
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Feuerhahn S, Egly JM. Tools to study DNA repair: what's in the box? Trends Genet 2008; 24:467-74. [DOI: 10.1016/j.tig.2008.07.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2008] [Revised: 07/15/2008] [Accepted: 07/15/2008] [Indexed: 01/06/2023]
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