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Lahnsteiner A, Craig SJC, Kamali K, Weissensteiner B, McGrath B, Risch A, Makova KD. In vivo detection of DNA secondary structures using permanganate/S1 footprinting with direct adapter ligation and sequencing (PDAL-Seq). Methods Enzymol 2024; 695:159-191. [PMID: 38521584 DOI: 10.1016/bs.mie.2023.12.003] [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: 03/25/2024]
Abstract
DNA secondary structures are essential elements of the genomic landscape, playing a critical role in regulating various cellular processes. These structures refer to G-quadruplexes, cruciforms, Z-DNA or H-DNA structures, amongst others (collectively called 'non-B DNA'), which DNA molecules can adopt beyond the B conformation. DNA secondary structures have significant biological roles, and their landscape is dynamic and can rearrange due to various factors, including changes in cellular conditions, temperature, and DNA-binding proteins. Understanding this dynamic nature is crucial for unraveling their functions in cellular processes. Detecting DNA secondary structures remains a challenge. Conventional methods, such as gel electrophoresis and chemical probing, have limitations in terms of sensitivity and specificity. Emerging techniques, including next-generation sequencing and single-molecule approaches, offer promise but face challenges since these techniques are mostly limited to only one type of secondary structure. Here we describe an updated version of a technique permanganate/S1 nuclease footprinting, which uses potassium permanganate to trap single-stranded DNA regions as found in many non-B structures, in combination with S1 nuclease digest and adapter ligation to detect genome-wide non-B formation. To overcome technical hurdles, we combined this method with direct adapter ligation and sequencing (PDAL-Seq). Furthermore, we established a user-friendly pipeline available on Galaxy to standardize PDAL-Seq data analysis. This optimized method allows the analysis of many types of DNA secondary structures that form in a living cell and will advance our knowledge of their roles in health and disease.
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Affiliation(s)
- Angelika Lahnsteiner
- Division of Cancer (Epi-)Genetics, Department of Biosciences and Medical Biology, Center for Tumor Biology and Immunology (CTBI), University of Salzburg, Salzburg, Austria; Cancer Cluster Salzburg, Salzburg, Austria.
| | - Sarah J C Craig
- Department of Biology, Penn State University, Wartik Laboratory, University Park, PA, United States
| | - Kaivan Kamali
- Department of Biology, Penn State University, Wartik Laboratory, University Park, PA, United States
| | | | - Barbara McGrath
- Department of Biology, Penn State University, Wartik Laboratory, University Park, PA, United States
| | - Angela Risch
- Division of Cancer (Epi-)Genetics, Department of Biosciences and Medical Biology, Center for Tumor Biology and Immunology (CTBI), University of Salzburg, Salzburg, Austria; Cancer Cluster Salzburg, Salzburg, Austria
| | - Kateryna D Makova
- Department of Biology, Penn State University, Wartik Laboratory, University Park, PA, United States.
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2
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Zhou M, Xu T, Xia K, Gao H, Li W, Zhai T, Gu H. Small DNAs That Specifically and Tightly Bind Transition Metal Ions. J Am Chem Soc 2023; 145:8776-8780. [PMID: 37052572 DOI: 10.1021/jacs.3c01276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
Specific DNA-binding to metal ions is a long-standing fundamental research topic with great potential to transform into nano/biotechnology and therapeutics applications. Herein, based on the mobility change of DNA in denaturing gels, we develop a selection strategy to discover a series of 40-45 nt small DNAs that can bind Zn2+ and Cd2+ specifically and tightly. The Zn2+- and Cd2+-bound DNA complexes can even tolerate harsh denaturing conditions of 8 M urea and 50 mM EDTA. The discovery not only exposes a new class of transition metal ion-binding DNAs but also provides potentially a new tool for targeting drug therapies based on metal ions.
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Affiliation(s)
- Mo Zhou
- Fudan University Shanghai Cancer Center, and the Shanghai Key Laboratory of Medical Epigenetics, Institutes of Biomedical Sciences, Shanghai Stomatological Hospital, Fudan University, Shanghai 200032, China
- Center for Medical Research and Innovation, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai 200433, China
| | - Tianbin Xu
- Fudan University Shanghai Cancer Center, and the Shanghai Key Laboratory of Medical Epigenetics, Institutes of Biomedical Sciences, Shanghai Stomatological Hospital, Fudan University, Shanghai 200032, China
| | - Kai Xia
- Fudan University Shanghai Cancer Center, and the Shanghai Key Laboratory of Medical Epigenetics, Institutes of Biomedical Sciences, Shanghai Stomatological Hospital, Fudan University, Shanghai 200032, China
| | - Haiqing Gao
- Fudan University Shanghai Cancer Center, and the Shanghai Key Laboratory of Medical Epigenetics, Institutes of Biomedical Sciences, Shanghai Stomatological Hospital, Fudan University, Shanghai 200032, China
| | - Wei Li
- Fudan University Shanghai Cancer Center, and the Shanghai Key Laboratory of Medical Epigenetics, Institutes of Biomedical Sciences, Shanghai Stomatological Hospital, Fudan University, Shanghai 200032, China
| | - Tingting Zhai
- Department of Chemical Biology, School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, National Center for Translational Medicine, and School of Global Health, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hongzhou Gu
- Fudan University Shanghai Cancer Center, and the Shanghai Key Laboratory of Medical Epigenetics, Institutes of Biomedical Sciences, Shanghai Stomatological Hospital, Fudan University, Shanghai 200032, China
- Center for Medical Research and Innovation, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai 200433, China
- Department of Chemical Biology, School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, National Center for Translational Medicine, and School of Global Health, Shanghai Jiao Tong University, Shanghai 200240, China
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3
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Koculi E, Cho SS. RNA Post-Transcriptional Modifications in Two Large Subunit Intermediates Populated in E. coli Cells Expressing Helicase Inactive R331A DbpA. Biochemistry 2022; 61:833-842. [PMID: 35481783 DOI: 10.1021/acs.biochem.2c00096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
23S ribosomal RNA (rRNA) of Escherichia coli 50S large ribosome subunit contains 26 post-transcriptionally modified nucleosides. Here, we determine the extent of modifications in the 35S and 45S large subunit intermediates, accumulating in cells expressing the helicase inactive DbpA protein, R331A, and the native 50S large subunit. The modifications we characterized are 3-methylpseudouridine, 2-methyladenine, 5-hydroxycytidine, and nine pseudouridines. These modifications were detected using 1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide metho-p-toluenesulfonate (CMCT) treatment followed by alkaline treatment. In addition, KMnO4 treatment of 23S rRNA was employed to detect 5-hydroxycytidine modification. CMCT and KMnO4 treatments produce chemical changes in modified nucleotides that cause reverse transcriptase misincorporations and deletions, which were detected employing next-generation sequencing. Our results show that the 2-methyladenine modification and seven uridines to pseudouridine isomerizations are present in both the 35S and 45S to similar extents as in the 50S. Hence, the enzymes that perform these modifications, namely, RluA, RluB, RluC, RluE, RluF, and RlmN, have already acted in the intermediates. Two uridines to pseudouridine isomerizations, the 3-methylpseudouridine and 5-hydroxycytidine modifications, are significantly less present in the 35S and 45S, as compared to the 50S. Therefore, the enzymes that incorporate these modifications, RluD, RlmH, and RlhA, are in the process of modifying the 35S and 45S or will incorporate these modifications during the later stages of ribosome assembly. Our study employs a novel high throughput and single nucleotide resolution technique for the detection of 2-methyladenine and two novel high throughput and single nucleotide resolution techniques for the detection of 5-hydroxycytidine.
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Affiliation(s)
- Eda Koculi
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205, United States
| | - Samuel S Cho
- Department of Physics, Wake Forest University, Winston-Salem, North Carolina 27109, United States.,Department of Computer Science, Wake Forest University, Winston-Salem, North Carolina 27109, United States
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4
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Cofsky JC, Soczek KM, Knott GJ, Nogales E, Doudna JA. CRISPR-Cas9 bends and twists DNA to read its sequence. Nat Struct Mol Biol 2022; 29:395-402. [PMID: 35422516 PMCID: PMC9189902 DOI: 10.1038/s41594-022-00756-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 03/01/2022] [Indexed: 12/28/2022]
Abstract
In bacterial defense and genome editing applications, the CRISPR-associated protein Cas9 searches millions of DNA base pairs to locate a 20-nucleotide, guide RNA-complementary target sequence that abuts a protospacer-adjacent motif (PAM). Target capture requires Cas9 to unwind DNA at candidate sequences using an unknown ATP-independent mechanism. Here we show that Cas9 sharply bends and undertwists DNA on PAM binding, thereby flipping DNA nucleotides out of the duplex and toward the guide RNA for sequence interrogation. Cryogenic-electron microscopy (cryo-EM) structures of Cas9-RNA-DNA complexes trapped at different states of the interrogation pathway, together with solution conformational probing, reveal that global protein rearrangement accompanies formation of an unstacked DNA hinge. Bend-induced base flipping explains how Cas9 'reads' snippets of DNA to locate target sites within a vast excess of nontarget DNA, a process crucial to both bacterial antiviral immunity and genome editing. This mechanism establishes a physical solution to the problem of complementarity-guided DNA search and shows how interrogation speed and local DNA geometry may influence genome editing efficiency.
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Affiliation(s)
- Joshua C Cofsky
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, USA
- Innovative Genomics Institute, University of California, Berkeley, CA, USA
| | - Katarzyna M Soczek
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, USA
- Innovative Genomics Institute, University of California, Berkeley, CA, USA
| | - Gavin J Knott
- Monash Biomedicine Discovery Institute, Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria, Australia
| | - Eva Nogales
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, USA
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA
- MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Jennifer A Doudna
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, USA.
- Innovative Genomics Institute, University of California, Berkeley, CA, USA.
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA.
- MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Department of Chemistry, University of California, Berkeley, CA, USA.
- Gladstone Institutes, University of California, San Francisco, CA, USA.
- Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA.
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5
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Xu T, Zhang C, Xia K, Li W, Cao Y, Gu H. Small DNAs that Bind Nickel(II) Specifically and Tightly. Anal Chem 2021; 93:14912-14917. [PMID: 34734709 DOI: 10.1021/acs.analchem.1c04034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Metal recognition by nucleic acids provides an intriguing route for biosensing of metal. Toward this goal, a key prerequisite is the acquisition of nucleic acids that can selectively respond to specific metals. Herein, we report for the first time the discovery of two small DNAs that can specifically bind Ni2+ and discriminate against similar ions, particularly, Co2+. Their minimal effective constructs are 60-70 nucleotides (nt) in length with Ni2+ binding even at harsh denaturing conditions of 8 M urea and 50 mM EDTA. Using isothermal titration calorimetry (ITC), we estimated the dissociation constant (KD) of a representative DNA to be 24.0 ± 4.5 μM, with a 9:1 stoichiometry of Ni2+ bound to DNA. As being engineered into nanosized particles, these DNAs can act like nanosponges to specifically adsorb Ni2+ from artificial wastewater, demonstrating their potential as a novel molecular tool for high-quality nickel enrichment and detection.
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Affiliation(s)
- Tianbin Xu
- Fudan University Shanghai Cancer Center, and the Shanghai Key Laboratory of Medical Epigenetics, Institutes of Biomedical Sciences, Shanghai Stomatological Hospital, Fudan University, Shanghai 200032, China.,Center for Medical Research and Innovation, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai 200433, China
| | - Canyu Zhang
- Fudan University Shanghai Cancer Center, and the Shanghai Key Laboratory of Medical Epigenetics, Institutes of Biomedical Sciences, Shanghai Stomatological Hospital, Fudan University, Shanghai 200032, China.,Center for Medical Research and Innovation, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai 200433, China
| | - Kai Xia
- Fudan University Shanghai Cancer Center, and the Shanghai Key Laboratory of Medical Epigenetics, Institutes of Biomedical Sciences, Shanghai Stomatological Hospital, Fudan University, Shanghai 200032, China.,Center for Medical Research and Innovation, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai 200433, China
| | - Wei Li
- Fudan University Shanghai Cancer Center, and the Shanghai Key Laboratory of Medical Epigenetics, Institutes of Biomedical Sciences, Shanghai Stomatological Hospital, Fudan University, Shanghai 200032, China.,Center for Medical Research and Innovation, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai 200433, China
| | - Yichun Cao
- Fudan University Shanghai Cancer Center, and the Shanghai Key Laboratory of Medical Epigenetics, Institutes of Biomedical Sciences, Shanghai Stomatological Hospital, Fudan University, Shanghai 200032, China.,Center for Medical Research and Innovation, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai 200433, China
| | - Hongzhou Gu
- Fudan University Shanghai Cancer Center, and the Shanghai Key Laboratory of Medical Epigenetics, Institutes of Biomedical Sciences, Shanghai Stomatological Hospital, Fudan University, Shanghai 200032, China.,Center for Medical Research and Innovation, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai 200433, China
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6
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Determining translocation orientations of nucleic acid helicases. Methods 2021; 204:160-171. [PMID: 34758393 PMCID: PMC9076756 DOI: 10.1016/j.ymeth.2021.11.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/29/2021] [Accepted: 11/02/2021] [Indexed: 11/20/2022] Open
Abstract
Helicase enzymes translocate along an RNA or DNA template with a defined polarity to unwind, separate, or remodel duplex strands for a variety of genome maintenance processes. Helicase mutations are commonly associated with a variety of diseases including aging, cancer, and neurodegeneration. Biochemical characterization of these enzymes has provided a wealth of information on the kinetics of unwinding and substrate preferences, and several high-resolution structures of helicases alone and bound to oligonucleotides have been solved. Together, they provide mechanistic insights into the structural translocation and unwinding orientations of helicases. However, these insights rely on structural inferences derived from static snapshots. Instead, continued efforts should be made to combine structure and kinetics to better define active translocation orientations of helicases. This review explores many of the biochemical and biophysical methods utilized to map helicase binding orientation to DNA or RNA substrates and includes several time-dependent methods to unequivocally map the active translocation orientation of these enzymes to better define the active leading and trailing faces.
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7
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Largy E, König A, Ghosh A, Ghosh D, Benabou S, Rosu F, Gabelica V. Mass Spectrometry of Nucleic Acid Noncovalent Complexes. Chem Rev 2021; 122:7720-7839. [PMID: 34587741 DOI: 10.1021/acs.chemrev.1c00386] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nucleic acids have been among the first targets for antitumor drugs and antibiotics. With the unveiling of new biological roles in regulation of gene expression, specific DNA and RNA structures have become very attractive targets, especially when the corresponding proteins are undruggable. Biophysical assays to assess target structure as well as ligand binding stoichiometry, affinity, specificity, and binding modes are part of the drug development process. Mass spectrometry offers unique advantages as a biophysical method owing to its ability to distinguish each stoichiometry present in a mixture. In addition, advanced mass spectrometry approaches (reactive probing, fragmentation techniques, ion mobility spectrometry, ion spectroscopy) provide more detailed information on the complexes. Here, we review the fundamentals of mass spectrometry and all its particularities when studying noncovalent nucleic acid structures, and then review what has been learned thanks to mass spectrometry on nucleic acid structures, self-assemblies (e.g., duplexes or G-quadruplexes), and their complexes with ligands.
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Affiliation(s)
- Eric Largy
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Alexander König
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Anirban Ghosh
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Debasmita Ghosh
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Sanae Benabou
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Frédéric Rosu
- Univ. Bordeaux, CNRS, INSERM, IECB, UMS 3033, F-33600 Pessac, France
| | - Valérie Gabelica
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
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8
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Helm M, Schmidt-Dengler MC, Weber M, Motorin Y. General Principles for the Detection of Modified Nucleotides in RNA by Specific Reagents. Adv Biol (Weinh) 2021; 5:e2100866. [PMID: 34535986 DOI: 10.1002/adbi.202100866] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 07/09/2021] [Indexed: 12/16/2022]
Abstract
Epitranscriptomics heavily rely on chemical reagents for the detection, quantification, and localization of modified nucleotides in transcriptomes. Recent years have seen a surge in mapping methods that use innovative and rediscovered organic chemistry in high throughput approaches. While this has brought about a leap of progress in this young field, it has also become clear that the different chemistries feature variegated specificity and selectivity. The associated error rates, e.g., in terms of false positives and false negatives, are in large part inherent to the chemistry employed. This means that even assuming technically perfect execution, the interpretation of mapping results issuing from the application of such chemistries are limited by intrinsic features of chemical reactivity. An important but often ignored fact is that the huge stochiometric excess of unmodified over-modified nucleotides is not inert to any of the reagents employed. Consequently, any reaction aimed at chemical discrimination of modified versus unmodified nucleotides has optimal conditions for selectivity that are ultimately anchored in relative reaction rates, whose ratio imposes intrinsic limits to selectivity. Here chemical reactivities of canonical and modified ribonucleosides are revisited as a basis for an understanding of the limits of selectivity achievable with chemical methods.
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Affiliation(s)
- Mark Helm
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-Universität, Staudingerweg 5, D-55128, Mainz, Germany
| | - Martina C Schmidt-Dengler
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-Universität, Staudingerweg 5, D-55128, Mainz, Germany
| | - Marlies Weber
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-Universität, Staudingerweg 5, D-55128, Mainz, Germany
| | - Yuri Motorin
- Université de Lorraine, CNRS, INSERM, UMS2008/US40 IBSLor, EpiRNA-Seq Core facility, Nancy, F-54000, France.,Université de Lorraine, CNRS, UMR7365 IMoPA, Nancy, F-54000, France
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9
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Putative Cooperative ATP-DnaA Binding to Double-Stranded DnaA Box and Single-Stranded DnaA-Trio Motif upon Helicobacter pylori Replication Initiation Complex Assembly. Int J Mol Sci 2021; 22:ijms22126643. [PMID: 34205762 PMCID: PMC8235120 DOI: 10.3390/ijms22126643] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/14/2021] [Accepted: 06/14/2021] [Indexed: 01/03/2023] Open
Abstract
oriC is a region of the bacterial chromosome at which the initiator protein DnaA interacts with specific sequences, leading to DNA unwinding and the initiation of chromosome replication. The general architecture of oriCs is universal; however, the structure of oriC and the mode of orisome assembly differ in distantly related bacteria. In this work, we characterized oriC of Helicobacter pylori, which consists of two DnaA box clusters and a DNA unwinding element (DUE); the latter can be subdivided into a GC-rich region, a DnaA-trio and an AT-rich region. We show that the DnaA-trio submodule is crucial for DNA unwinding, possibly because it enables proper DnaA oligomerization on ssDNA. However, we also observed the reverse effect: DNA unwinding, enabling subsequent DnaA-ssDNA oligomer formation-stabilized DnaA binding to box ts1. This suggests the interplay between DnaA binding to ssDNA and dsDNA upon DNA unwinding. Further investigation of the ts1 DnaA box revealed that this box, together with the newly identified c-ATP DnaA box in oriC1, constitute a new class of ATP-DnaA boxes. Indeed, in vitro ATP-DnaA unwinds H. pylori oriC more efficiently than ADP-DnaA. Our results expand the understanding of H. pylori orisome formation, indicating another regulatory pathway of H. pylori orisome assembly.
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10
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Responses of DNA Mismatch Repair Proteins to a Stable G-Quadruplex Embedded into a DNA Duplex Structure. Int J Mol Sci 2020; 21:ijms21228773. [PMID: 33233554 PMCID: PMC7699706 DOI: 10.3390/ijms21228773] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/16/2020] [Accepted: 11/18/2020] [Indexed: 12/26/2022] Open
Abstract
DNA mismatch repair (MMR) plays a crucial role in the maintenance of genomic stability. The main MMR protein, MutS, was recently shown to recognize the G-quadruplex (G4) DNA structures, which, along with regulatory functions, have a negative impact on genome integrity. Here, we studied the effect of G4 on the DNA-binding activity of MutS from Rhodobacter sphaeroides (methyl-independent MMR) in comparison with MutS from Escherichia coli (methyl-directed MMR) and evaluated the influence of a G4 on the functioning of other proteins involved in the initial steps of MMR. For this purpose, a new DNA construct was designed containing a biologically relevant intramolecular stable G4 structure flanked by double-stranded regions with the set of DNA sites required for MMR initiation. The secondary structure of this model was examined using NMR spectroscopy, chemical probing, fluorescent indicators, circular dichroism, and UV spectroscopy. The results unambiguously showed that the d(GGGT)4 motif, when embedded in a double-stranded context, adopts a G4 structure of a parallel topology. Despite strong binding affinities of MutS and MutL for a G4, the latter is not recognized by E. coli MMR as a signal for repair, but does not prevent MMR processing when a G4 and G/T mismatch are in close proximity.
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11
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Cofsky JC, Karandur D, Huang CJ, Witte IP, Kuriyan J, Doudna JA. CRISPR-Cas12a exploits R-loop asymmetry to form double-strand breaks. eLife 2020; 9:e55143. [PMID: 32519675 PMCID: PMC7286691 DOI: 10.7554/elife.55143] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 04/08/2020] [Indexed: 12/17/2022] Open
Abstract
Type V CRISPR-Cas interference proteins use a single RuvC active site to make RNA-guided breaks in double-stranded DNA substrates, an activity essential for both bacterial immunity and genome editing. The best-studied of these enzymes, Cas12a, initiates DNA cutting by forming a 20-nucleotide R-loop in which the guide RNA displaces one strand of a double-helical DNA substrate, positioning the DNase active site for first-strand cleavage. However, crystal structures and biochemical data have not explained how the second strand is cut to complete the double-strand break. Here, we detect intrinsic instability in DNA flanking the RNA-3' side of R-loops, which Cas12a can exploit to expose second-strand DNA for cutting. Interestingly, DNA flanking the RNA-5' side of R-loops is not intrinsically unstable. This asymmetry in R-loop structure may explain the uniformity of guide RNA architecture and the single-active-site cleavage mechanism that are fundamental features of all type V CRISPR-Cas systems.
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Affiliation(s)
- Joshua C Cofsky
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Deepti Karandur
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
| | - Carolyn J Huang
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Isaac P Witte
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - John Kuriyan
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
- MBIB Division, Lawrence Berkeley National LaboratoryBerkeleyUnited States
| | - Jennifer A Doudna
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
- MBIB Division, Lawrence Berkeley National LaboratoryBerkeleyUnited States
- Innovative Genomics Institute, University of California, BerkeleyBerkeleyUnited States
- Gladstone Institutes, University of California, San FranciscoSan FranciscoUnited States
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12
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Kouzine F, Wojtowicz D, Yamane A, Casellas R, Przytycka TM, Levens DL. In Vivo Chemical Probing for G-Quadruplex Formation. Methods Mol Biol 2020; 2035:369-382. [PMID: 31444763 DOI: 10.1007/978-1-4939-9666-7_23] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
While DNA inside the cells is predominantly canonical right-handed double helix, guanine-rich DNAs have potential to fold into four-stranded structures that contain stacks of G-quartets (G4 DNA quadruplex). Genome sequencing has revealed G4 sequences tend to localize at the gene control regions, especially in the promoters of oncogenes. A growing body of evidence indicates that G4 DNA quadruplexes might have important regulatory roles in genome function, highlighting the need for techniques to detect genome-wide folding of DNA into this structure. Potassium permanganate in vivo treatment of cells results in oxidizing of nucleotides in single-stranded DNA regions that accompany G4 DNA quadruplexes formation, providing an excellent probe for the conformational state of DNA inside the living cells. Here, we describe a permanganate-based methodology to detect G4 DNA quadruplex, genome-wide. This methodology combined with high-throughput sequencing provides a snapshot of the DNA conformation over the whole genome in vivo.
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Affiliation(s)
- Fedor Kouzine
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health (USA), Bethesda, MD, USA
| | - Damian Wojtowicz
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health (USA), Bethesda, MD, USA
| | - Arito Yamane
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health (USA), Bethesda, MD, USA
| | - Rafael Casellas
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health (USA), Bethesda, MD, USA
| | - Teresa M Przytycka
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health (USA), Bethesda, MD, USA
| | - David L Levens
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health (USA), Bethesda, MD, USA.
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Al Hageh C, Al Assaad M, El Masri Z, Samaan N, El-Sibai M, Khalil C, Khnayzer RS. A long-lived cuprous bis-phenanthroline complex for the photodynamic therapy of cancer. Dalton Trans 2018; 47:4959-4967. [DOI: 10.1039/c8dt00140e] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
An earth-abundant cuprous bis-phenanthroline photosensitizer showed potential use in the photodynamic therapy of cancer.
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Affiliation(s)
- Cynthia Al Hageh
- Department of Natural Sciences
- Lebanese American University
- Chouran
- Lebanon
| | - Majd Al Assaad
- Department of Natural Sciences
- Lebanese American University
- Chouran
- Lebanon
| | - Zeinab El Masri
- Department of Natural Sciences
- Lebanese American University
- Chouran
- Lebanon
| | - Nawar Samaan
- Department of Natural Sciences
- Lebanese American University
- Chouran
- Lebanon
| | - Mirvat El-Sibai
- Department of Natural Sciences
- Lebanese American University
- Chouran
- Lebanon
| | - Christian Khalil
- Department of Natural Sciences
- Lebanese American University
- Chouran
- Lebanon
| | - Rony S. Khnayzer
- Department of Natural Sciences
- Lebanese American University
- Chouran
- Lebanon
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14
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Sekibo DAT, Fox KR. The effects of DNA supercoiling on G-quadruplex formation. Nucleic Acids Res 2017; 45:12069-12079. [PMID: 29036619 PMCID: PMC5716088 DOI: 10.1093/nar/gkx856] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 09/13/2017] [Indexed: 01/06/2023] Open
Abstract
Guanine-rich DNAs can fold into four-stranded structures that contain stacks of G-quartets. Bioinformatics studies have revealed that G-rich sequences with the potential to adopt these structures are unevenly distributed throughout genomes, and are especially found in gene promoter regions. With the exception of the single-stranded telomeric DNA, all genomic G-rich sequences will always be present along with their C-rich complements, and quadruplex formation will be in competition with the corresponding Watson–Crick duplex. Quadruplex formation must therefore first require local dissociation (melting) of the duplex strands. Since negative supercoiling is known to facilitate the formation of alternative DNA structures, we have investigated G-quadruplex formation within negatively supercoiled DNA plasmids. Plasmids containing multiple copies of (G3T)n and (G3T4)n repeats, were probed with dimethylsulphate, potassium permanganate and S1 nuclease. While dimethylsulphate footprinting revealed some evidence for G-quadruplex formation in (G3T)n sequences, this was not affected by supercoiling, and permanganate failed to detect exposed thymines in the loop regions. (G3T4)n sequences were not protected from DMS and showed no reaction with permanganate. Similarly, both S1 nuclease and 2D gel electrophoresis of DNA topoisomers did not detect any supercoil-dependent structural transitions. These results suggest that negative supercoiling alone is not sufficient to drive G-quadruplex formation.
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Affiliation(s)
- Doreen A T Sekibo
- Biological Sciences, Life Sciences Building 85, University of Southampton, Southampton SO17 1BJ, UK
| | - Keith R Fox
- Biological Sciences, Life Sciences Building 85, University of Southampton, Southampton SO17 1BJ, UK
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15
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Permanganate/S1 Nuclease Footprinting Reveals Non-B DNA Structures with Regulatory Potential across a Mammalian Genome. Cell Syst 2017; 4:344-356.e7. [PMID: 28237796 DOI: 10.1016/j.cels.2017.01.013] [Citation(s) in RCA: 134] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 09/06/2016] [Accepted: 01/13/2017] [Indexed: 12/11/2022]
Abstract
DNA in cells is predominantly B-form double helix. Though certain DNA sequences in vitro may fold into other structures, such as triplex, left-handed Z form, or quadruplex DNA, the stability and prevalence of these structures in vivo are not known. Here, using computational analysis of sequence motifs, RNA polymerase II binding data, and genome-wide potassium permanganate-dependent nuclease footprinting data, we map thousands of putative non-B DNA sites at high resolution in mouse B cells. Computational analysis associates these non-B DNAs with particular structures and indicates that they form at locations compatible with an involvement in gene regulation. Further analyses support the notion that non-B DNA structure formation influences the occupancy and positioning of nucleosomes in chromatin. These results suggest that non-B DNAs contribute to the control of a variety of critical cellular and organismal processes.
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16
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Tserovski L, Helm M. Diastereoselectivity of 5-Methyluridine Osmylation Is Inverted inside an RNA Chain. Bioconjug Chem 2016; 27:2188-97. [PMID: 27540864 DOI: 10.1021/acs.bioconjchem.6b00403] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In this study, we investigated the reaction of the osmium tetroxide-bipyridine complex with pyrimidines in RNA. This reagent, which reacts with the diastereotopic 5-6 double bond, thus leading to the formation of two diastereomers, was used in the past to label thymidine and 5-methylcytosine in DNA. In light of the growing interest in post-transcriptional RNA modifications, we addressed the question of whether this reagent could be used for labeling of the naturally occurring RNA modifications 5-methylcytosine and 5-methyluridine. On nucleoside level, 5-methylcytosine and 5-methyluridine revealed a 5- and 12-fold preference, respectively, over their nonmethylated equivalents. Performing the reaction on an RNA level, we could show that the steric environment of a pentanucleotide has a major detrimental impact on the reaction rate of osmylation. Interestingly, this drop in reactivity was due to a dramatic change in diastereoselectivity, which in turn resulted from impediment of the preferred attack via the si side. Thus, while on the nucleoside level, the absolute configuration of the major product of osmylation of 5-methyluridine was (5R,6S)-5-methyluridine glycol-dioxoosmium-bipyridine, reaction with an RNA pentanucleotide afforded the corresponding (5S,6R)-diastereomer as the major product. The change in diastereoselectivity lead to an almost complete loss of selectivity toward 5-methylcytosine in a pentanucleotide context, while 5-methyluridine remained about 8 times more reactive than the canonical pyrimidines. On the basis of these findings, we evaluate the usefulness of osmium tetroxide-bipyridine as a potential label for the 5-methyluridine modification in transcriptome-wide studies.
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Affiliation(s)
- Lyudmil Tserovski
- Institute of Pharmacy and Biochemistry, University of Mainz , D-55128 Mainz, Germany
| | - Mark Helm
- Institute of Pharmacy and Biochemistry, University of Mainz , D-55128 Mainz, Germany
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17
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Reynolds KA, Raney VM, Raney KD. Probing RNA translocases with DNA. Methods Mol Biol 2015; 1259:275-91. [PMID: 25579592 DOI: 10.1007/978-1-4939-2214-7_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
For some helicases, it is possible to investigate RNA translocase activity on DNA substrates because the enzyme acts on both substrates. Potassium permanganate (KMnO4) footprinting is a method used to chemically probe the conformation of DNA as well as the binding of proteins. Combining footprinting methods with rapid mixing methods that utilize a chemical quench-flow instrument can enable tracking of the translocase with nucleotide resolution.
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Affiliation(s)
- Kimberly A Reynolds
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, 4301 W. Markham St., Little Rock, AR, USA
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18
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Aarattuthodiyil S, Byrd AK, Raney KD. Simultaneous binding to the tracking strand, displaced strand and the duplex of a DNA fork enhances unwinding by Dda helicase. Nucleic Acids Res 2014; 42:11707-20. [PMID: 25249618 PMCID: PMC4191417 DOI: 10.1093/nar/gku845] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Interactions between helicases and the tracking strand of a DNA substrate are well-characterized; however, the role of the displaced strand is a less understood characteristic of DNA unwinding. Dda helicase exhibited greater processivity when unwinding a DNA fork compared to a ss/ds DNA junction substrate. The lag phase in the unwinding progress curve was reduced for the forked DNA compared to the ss/ds junction. Fewer kinetic steps were required to unwind the fork compared to the ss/ds junction, suggesting that binding to the fork leads to disruption of the duplex. DNA footprinting confirmed that interaction of Dda with a fork leads to two base pairs being disrupted whereas no disruption of base pairing was observed with the ss/ds junction. Neutralization of the phosphodiester backbone resulted in a DNA-footprinting pattern similar to that observed with the ss/ds junction, consistent with disruption of the interaction between Dda and the displaced strand. Several basic residues in the 1A domain which were previously proposed to bind to the incoming duplex DNA were replaced with alanines, resulting in apparent loss of interaction with the duplex. Taken together, these results suggest that Dda interaction with the tracking strand, displaced strand and duplex coordinates DNA unwinding.
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Affiliation(s)
- Suja Aarattuthodiyil
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Alicia K Byrd
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Kevin D Raney
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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19
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Li J, Liu Y, Rhee HS, Ghosh SKB, Bai L, Pugh BF, Gilmour DS. Kinetic competition between elongation rate and binding of NELF controls promoter-proximal pausing. Mol Cell 2013; 50:711-22. [PMID: 23746353 DOI: 10.1016/j.molcel.2013.05.016] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 04/03/2013] [Accepted: 05/10/2013] [Indexed: 11/29/2022]
Abstract
Pausing of RNA polymerase II (Pol II) 20-60 bp downstream of transcription start sites is a major checkpoint during transcription in animal cells. Mechanisms that control pausing are largely unknown. We developed permanganate-ChIP-seq to evaluate the state of Pol II at promoters throughout the Drosophila genome, and a biochemical system that reconstitutes promoter-proximal pausing to define pausing mechanisms. Stable open complexes of Pol II are largely absent from the transcription start sites of most mRNA genes but are present at snRNA genes and the highly transcribed heat shock genes following their induction. The location of the pause is influenced by the timing between when NELF loads onto Pol II and how fast Pol II escapes the promoter region. Our biochemical analysis reveals that the sequence-specific transcription factor, GAF, orchestrates efficient pausing by recruiting NELF to promoters before transcription initiation and by assisting in loading NELF onto Pol II after initiation.
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Affiliation(s)
- Jian Li
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
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20
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Raney VM, Reynolds KA, Harrison MK, Harrison DK, Cameron CE, Raney KD. Binding by the hepatitis C virus NS3 helicase partially melts duplex DNA. Biochemistry 2012; 51:7596-607. [PMID: 22916835 DOI: 10.1021/bi300654v] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Binding of NS3 helicase to DNA was investigated by footprinting with KMnO(4), which reacts preferentially with thymidine residues in single-stranded DNA (ssDNA) compared to those in double-stranded DNA (dsDNA). A distinct pattern of reactivity was observed on ssDNA, which repeated every 8 nucleotides (nt) and is consistent with the known binding site size of NS3. Binding to a DNA substrate containing a partial duplex was also investigated. The DNA contained a 15 nt overhang made entirely of thymidine residues adjacent to a 22 bp duplex that contained thymidine at every other position. Surprisingly, the KMnO(4) reactivity pattern extended from the ssDNA into the dsDNA region of the substrate. Lengthening the partial duplex to 30 bp revealed a similar pattern extending from the ssDNA into the dsDNA, indicating that NS3 binds within the duplex region. Increasing the length of the ssDNA portion of the partial duplex by 4 nt resulted in a shift in the footprinting pattern for the ssDNA by 4 nt, which is consistent with binding to the 3'-end of the ssDNA. However, the footprinting pattern in the dsDNA region was shifted by only 1-2 bp, indicating that binding to the ssDNA-dsDNA region was preferred. Footprinting performed as a function of time indicated that NS3 binds to the ssDNA rapidly, followed by slower binding to the duplex. Hence, multiple molecules of NS3 can bind along a ssDNA-dsDNA partial duplex by interacting with the ssDNA as well as the duplex DNA.
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Affiliation(s)
- Veronica M Raney
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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21
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Ferrier M, Weck PF, Poineau F, Kim E, Stebbins A, Ma L, Sattelberger AP, Czerwinski KR. First evidence for the formation of technetium oxosulfide complexes: synthesis, structure and characterization. Dalton Trans 2012; 41:6291-8. [DOI: 10.1039/c2dt30063j] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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22
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Logvina NA, Yakubovskaya MG, Dolinnaya NG. Rapid photometric detection of thymine residues partially flipped out of double helix as a method for direct scanning of point mutations and apurinic DNA sites. BIOCHEMISTRY (MOSCOW) 2011; 76:245-52. [PMID: 21568858 DOI: 10.1134/s0006297911020118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A spectroscopic assay for detection of extrahelical thymine residues in DNA heteroduplexes under their modification by potassium permanganate has been developed. The assay is based on increase in absorbance at 420 nm due to accumulation of thymidine oxidation intermediates and soluble manganese dioxide. The analysis was carried out using a set of 19-bp DNA duplexes containing unpaired thymidines opposite tetrahydrofuranyl derivatives mimicking a widespread DNA damage (apurinic (AP) sites) and a library of 50-bp DNA duplexes containing all types of base mismatches in different surroundings. The relation between the selectivity of unpaired T oxidation and the thermal stability of DNA double helix was investigated. The method described here was shown to discriminate between DNA duplexes with one or two AP sites and to reveal thymine-containing mismatches and all noncanonical base pairs in AT-surroundings. Comparative results of CCM analysis and the rapid photometric assay for mismatch detection are demonstrated for the first time in the same model system. The chemical reactivity of target thymines was shown to correlate with local disturbance of double helix at the mismatch site. As the spectroscopic assay does not require the DNA cleavage reaction and gel electrophoresis, it can be easily automated and used for primary screening of somatic mutations.
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Affiliation(s)
- N A Logvina
- Chemical Faculty, Lomonosov Moscow State University, Russia
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23
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Parr C, Pierce SE, Smith SI, Brodbelt JS. Investigation of the Reactivity of Oligodeoxynucleotides with Glyoxal and KMnO(4) Chemical Probes by Electrospray Ionization Mass Spectrometry. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2011; 304:115-123. [PMID: 21743793 PMCID: PMC3130548 DOI: 10.1016/j.ijms.2010.06.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The reactions of two well-known chemical probes, glyoxal and potassium permanganate (KMnO(4)), with oligodeoxynucleotides were monitored by electrospray ionization (ESI) mass spectrometry to evaluate the influence of the sequence of DNA, its secondary structure, and interactions with associated ligands on the reactivity of the two probes. Glyoxal, a guanine-reactive probe, incorporated a mass shift of 58 Da, and potassium permanganate (KMnO(4)) is a thymine-reactive probe that resulted in a mass shift of 34 Da. The reactions depended on the accessibility of the nucleobases, and the peak abundances of the adducts in the ESI-mass spectra were used to quantify the extent of the chemical probe reactions. In this study, both mixed-base sequences were studied as well as control sequences in which one reactive site was located at the terminus or center of the oligodeoxynucleotide while the surrounding bases were a second, different nucleobase. In addition, the reactions of the chemical probes with non-covalent complexes formed between DNA and either actinomycin D or ethidium bromide, both known to interact with single strand DNA, were evaluated.
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Affiliation(s)
- Carol Parr
- Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX 78712
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24
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Behm-Ansmant I, Helm M, Motorin Y. Use of specific chemical reagents for detection of modified nucleotides in RNA. J Nucleic Acids 2011; 2011:408053. [PMID: 21716696 PMCID: PMC3118635 DOI: 10.4061/2011/408053] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Accepted: 01/24/2011] [Indexed: 12/18/2022] Open
Abstract
Naturally occurring cellular RNAs contain an impressive number of chemically distinct modified residues which appear posttranscriptionally, as a result of specific action of the corresponding RNA modification enzymes. Over 100 different chemical modifications have been identified and characterized up to now. Identification of the chemical nature and exact position of these modifications is typically based on 2D-TLC analysis of nucleotide digests, on HPLC coupled with mass spectrometry, or on the use of primer extension by reverse transcriptase. However, many modified nucleotides are silent in reverse transcription, since the presence of additional chemical groups frequently does not change base-pairing properties. In this paper, we give a summary of various chemical approaches exploiting the specific reactivity of modified nucleotides in RNA for their detection.
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Affiliation(s)
- Isabelle Behm-Ansmant
- Laboratoire ARN-RNP Maturation-Structure-Fonction, Enzymologie Moléculaire et Structurale (AREMS), UMR 7214 CNRS-UHP, Nancy Université, boulevard des Aiguillettes, BP 70239, 54506 Vandoeuvre-les-Nancy, France
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25
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Sheikh RA, Al-Nowaiser F, Malik MA, Al-Youbi A, Khan Z. Effect of cationic micelles of cetyltrimethylammonium bromide on the MnO4− oxidation of valine. Colloids Surf A Physicochem Eng Asp 2010. [DOI: 10.1016/j.colsurfa.2010.05.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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26
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Brodbelt JS. Evaluation of DNA/Ligand interactions by electrospray ionization mass spectrometry. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2010; 3:67-87. [PMID: 20636034 DOI: 10.1146/annurev.anchem.111808.073627] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Electrospray ionization mass spectrometry (ESI-MS) has enabled the detection and characterization of DNA/ligand complexes, including evaluation of both relative binding affinities and selectivities of DNA-interactive ligands. The noncovalent complexes that are transferred from the solution to the gas phase retain the signature of the native species, thus allowing the use of MS to screen DNA/ligand complexes, reveal the stoichiometries of the complexes, and provide insight into the nature of the interactions. Ligands that bind to DNA via metal-mediated modes and those that bind to unusual DNA structures, such as quadruplexes, are amenable to ESI. Chemical probe methods applied to DNA/ligand complexes with ESI-MS detection afford information about ligand-binding sites and conformational changes of DNA that occur upon ligand binding.
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Affiliation(s)
- Jennifer S Brodbelt
- Department of Chemistry and Biochemistry, University of Texas, Austin, 78712, USA.
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27
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Poineau F, Weck PF, German K, Maruk A, Kirakosyan G, Lukens W, Rego DB, Sattelberger AP, Czerwinski KR. Speciation of heptavalent technetium in sulfuric acid: structural and spectroscopic studies. Dalton Trans 2010; 39:8616-9. [DOI: 10.1039/c0dt00695e] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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28
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Motorin Y, Lyko F, Helm M. 5-methylcytosine in RNA: detection, enzymatic formation and biological functions. Nucleic Acids Res 2009; 38:1415-30. [PMID: 20007150 PMCID: PMC2836557 DOI: 10.1093/nar/gkp1117] [Citation(s) in RCA: 240] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The nucleobase modification 5-methylcytosine (m5C) is widespread both in DNA and different cellular RNAs. The functions and enzymatic mechanisms of DNA m5C-methylation were extensively studied during the last decades. However, the location, the mechanism of formation and the cellular function(s) of the same modified nucleobase in RNA still remain to be elucidated. The recent development of a bisulfite sequencing approach for efficient m5C localization in various RNA molecules puts ribo-m5C in a highly privileged position as one of the few RNA modifications whose detection is amenable to PCR-based amplification and sequencing methods. Additional progress in the field also includes the characterization of several specific RNA methyltransferase enzymes in various organisms, and the discovery of a new and unexpected link between DNA and RNA m5C-methylation. Numerous putative RNA:m5C-MTases have now been identified and are awaiting characterization, including the identification of their RNA substrates and their related cellular functions. In order to bring these recent exciting developments into perspective, this review provides an ordered overview of the detection methods for RNA methylation, of the biochemistry, enzymology and molecular biology of the corresponding modification enzymes, and discusses perspectives for the emerging biological functions of these enzymes.
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Affiliation(s)
- Yuri Motorin
- Laboratoire ARN-RNP Maturation-Structure-Fonction, Enzymologie Moléculaire et Structurale (AREMS), UMR 7214 CNRS-UHP Faculté des Sciences et Techniques, Université Henri Poincaré, Nancy 1, Bld des Aiguillettes, BP 70239, 54506 Vandoeuvre-les-Nancy, France
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29
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30
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Fernandez AG, Anderson JN. Nucleosome Positioning Determinants. J Mol Biol 2007; 371:649-68. [PMID: 17586522 DOI: 10.1016/j.jmb.2007.05.090] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2007] [Revised: 05/22/2007] [Accepted: 05/29/2007] [Indexed: 11/23/2022]
Abstract
A previous report demonstrated that one site in a nucleosome assembled onto a synthetic positioning sequence known as Fragment 67 is hypersensitive to permanganate. The site is required for positioning activity and is located 1.5 turns from the dyad, which is a region of high DNA curvature in the nucleosome. Here, the permanganate sensitivity of the nucleosome positioning Fragment 601 was examined in order to expand the dataset of nucleosome sequences containing KMnO(4) hypersensitive sites. The hyperreactive T residue in the six sites detected as well as the one in Fragment 67 and three in the 5 S rDNA positioning sequence were contained within a TA step. Seven of the ten sequences were of the form CTAGPuG or the related sequence TTAAPu. These motifs were also found in the binding sites of several transcriptional regulatory proteins that kink DNA. In order to assess the significance of these sites, the 10 bp positioning determinant in Fragment 67 was removed and replaced by the nine sequences from the 5 S rDNA and Fragment 601. The results demonstrated that these derivative fragments promoted high nucleosome stability and positioning as compared to a control sequence that contained an AT step in place of the TA step. The importance of the TA step was further tested by making single base-pair substitutions in Fragment 67 and the results revealed that stability and positioning activity followed the order: TA>TG>TT>/=TC approximately GG approximately GA approximately AT. Sequences flanking the TA step were also shown to be critical for nucleosome stability and positioning. Nucleosome positioning was restored to near wild-type levels with (CTG)(3), which can form slipped stranded structures and with one base bulges that kink DNA. The results of this study suggest that local DNA structures are important for positioning and that single base-pair changes at these sites could have profound effects on those genomic functions that depend on ordered nucleosomes.
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Affiliation(s)
- Alfonso G Fernandez
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907-1392, USA
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31
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Mazzitelli CL, Brodbelt JS. Probing ligand binding to duplex DNA using KMnO4 reactions and electrospray ionization tandem mass spectrometry. Anal Chem 2007; 79:4636-47. [PMID: 17508717 PMCID: PMC2531255 DOI: 10.1021/ac070145p] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
An electrospray ionization tandem mass spectrometry (ESI-MS/MS) strategy employing the thymine-selective KMnO4 oxidation reaction to detect conformational changes and ligand binding sites in noncovalent DNA/drug complexes is reported. ESI-MS/MS is used to detect specific mass shifts of the DNA ions that are associated with the oxidation of thymines. This KMnO4 oxidation/ESI-MS/MS approach is an alternative to conventional gel-based oxidation methods and affords excellent sensitivity while eliminating the reliance on radiolabeled DNA. Comparison of single-strand versus duplex DNA indicates that the duplexes exhibit a significant resistance to the reaction, thus confirming that the oxidation process is favored for unwound or single-strand regions of DNA. DNA complexes containing different drugs including echinomycin, actinomycin-D, ethidium bromide, Hoechst 33342, and cis-C1 were subjected to the oxidation reaction. Echinomycin, a ligand with a bisintercalative binding mode, was found to induce the greatest KMnO4 reactivity, while Hoechst 33342, a minor groove binder, caused no increase in the oxidation of DNA. The oxidation of echinomycin/DNA complexes containing duplexes with different sequences and lengths was also assessed. Duplexes with thymines closer to the terminal ends of the duplex demonstrated a greater increase in the degree of oxidation than those with thymines in the middle of the sequence. Collisional activated dissociation (CAD) and infrared multiphoton dissociation (IRMPD) experiments were used to determine the site of oxidation based on oligonucleotide fragmentation patterns.
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Affiliation(s)
- Carolyn L Mazzitelli
- Department of Chemistry and Biochemistry, 1 University Station A5300, University of Texas at Austin, Austin, Texas 78712, USA
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32
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Sano T, Higaki T, Handa K, Kadota Y, Kuchitsu K, Hasezawa S, Hoffmann A, Endter J, Zimmermann U, Hedrich R, Roitsch T. Calcium ions are involved in the delay of plant cell cycle progression by abiotic stresses. FEBS Lett 2006; 580:597-602. [PMID: 16405971 DOI: 10.1016/j.febslet.2005.12.074] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2005] [Revised: 12/20/2005] [Accepted: 12/23/2005] [Indexed: 11/29/2022]
Abstract
Higher plants respond to environmental stresses by a sequence of reactions which include the reduction of growth by affecting cell division. It has been shown that calcium ions plays a role as a second messenger in mediating various defence responses under environmental stresses. In this study, the role of calcium ions on cell cycle progression under abiotic stresses has been examined in tobacco BY-2 suspension culture cells. Using synchronized BY-2 cells expressing the endogenous calcium sensor aequorin as experimental system, we could show that oxidative and hypoosmotic stress both induce an increase of intracellular calcium and cause a delay of the cell cycle. The inhibitory effect of these abiotic stress stimuli on cell cycle progression could be mimicked by increasing the intracellular calcium concentration via application of an external electrical field. Likewise, depletion of calcium ions in the culture medium suppressed the effect of the stimuli tested. These results demonstrate that calcium signalling is involved in the regulation of cell cycle progression in response to abiotic stress.
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Affiliation(s)
- Toshio Sano
- Lehrstuhl für Molekulare Pflanzenphysiologie und Biophysik, Julius-von-Sachs-Institut für Biowissenschaften, Universität Würzburg, 97082 Würzburg, Germany.
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Bui CT, Sam LA, Cotton RGH. UV–visible spectral identification of the solution-phase and solid-phase permanganate oxidation reactions of thymine acetic acid. Bioorg Med Chem Lett 2004; 14:1313-5. [PMID: 14980689 DOI: 10.1016/j.bmcl.2003.12.070] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2003] [Accepted: 12/05/2003] [Indexed: 10/26/2022]
Abstract
Solution-phase and solid-phase permanganate oxidation reactions of thymine acetic acid were investigated by spectroscopy. The spectral data showed the formation of a stable organomanganese intermediate, which was responsible for the rise in the absorbance at 420 nm. This result enables unambiguous interpretation of the absorbance change at 420 nm, as the intermediate permanganate ions could be isolated on the solid supports.
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Affiliation(s)
- Chinh T Bui
- Genomic Disorders Research Centre and the University of Melbourne, 7th Floor, Daly Wing, St. Vincent Hospital, 35 Victoria Parade, Fitzroy, Melbourne, Victoria 3065, Australia.
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