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Bartas M, Slychko K, Červeň J, Pečinka P, Arndt-Jovin DJ, Jovin TM. Extensive Bioinformatics Analyses Reveal a Phylogenetically Conserved Winged Helix (WH) Domain (Zτ) of Topoisomerase IIα, Elucidating Its Very High Affinity for Left-Handed Z-DNA and Suggesting Novel Putative Functions. Int J Mol Sci 2023; 24:10740. [PMID: 37445918 DOI: 10.3390/ijms241310740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/13/2023] [Accepted: 06/22/2023] [Indexed: 07/15/2023] Open
Abstract
The dynamic processes operating on genomic DNA, such as gene expression and cellular division, lead inexorably to topological challenges in the form of entanglements, catenanes, knots, "bubbles", R-loops, and other outcomes of supercoiling and helical disruption. The resolution of toxic topological stress is the function attributed to DNA topoisomerases. A prominent example is the negative supercoiling (nsc) trailing processive enzymes such as DNA and RNA polymerases. The multiple equilibrium states that nscDNA can adopt by redistribution of helical twist and writhe include the left-handed double-helical conformation known as Z-DNA. Thirty years ago, one of our labs isolated a protein from Drosophila cells and embryos with a 100-fold greater affinity for Z-DNA than for B-DNA, and identified it as topoisomerase II (gene Top2, orthologous to the human UniProt proteins TOP2A and TOP2B). GTP increased the affinity and selectivity for Z-DNA even further and also led to inhibition of the isomerase enzymatic activity. An allosteric mechanism was proposed, in which topoII acts as a Z-DNA-binding protein (ZBP) to stabilize given states of topological (sub)domains and associated multiprotein complexes. We have now explored this possibility by comprehensive bioinformatic analyses of the available protein sequences of topoII representing organisms covering the whole tree of life. Multiple alignment of these sequences revealed an extremely high level of evolutionary conservation, including a winged-helix protein segment, here denoted as Zτ, constituting the putative structural homolog of Zα, the canonical Z-DNA/Z-RNA binding domain previously identified in the interferon-inducible RNA Adenosine-to-Inosine-editing deaminase, ADAR1p150. In contrast to Zα, which is separate from the protein segment responsible for catalysis, Zτ encompasses the active site tyrosine of topoII; a GTP-binding site and a GxxG sequence motif are in close proximity. Quantitative Zτ-Zα similarity comparisons and molecular docking with interaction scoring further supported the "B-Z-topoII hypothesis" and has led to an expanded mechanism for topoII function incorporating the recognition of Z-DNA segments ("Z-flipons") as an inherent and essential element. We further propose that the two Zτ domains of the topoII homodimer exhibit a single-turnover "conformase" activity on given G(ate) B-DNA segments ("Z-flipins"), inducing their transition to the left-handed Z-conformation. Inasmuch as the topoII-Z-DNA complexes are isomerase inactive, we infer that they fulfill important structural roles in key processes such as mitosis. Topoisomerases are preeminent targets of anti-cancer drug discovery, and we anticipate that detailed elucidation of their structural-functional interactions with Z-DNA and GTP will facilitate the design of novel, more potent and selective anti-cancer chemotherapeutic agents.
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Affiliation(s)
- Martin Bartas
- Department of Biology and Ecology, University of Ostrava, 710 00 Ostrava, Czech Republic
| | - Kristyna Slychko
- Department of Biology and Ecology, University of Ostrava, 710 00 Ostrava, Czech Republic
| | - Jiří Červeň
- Department of Biology and Ecology, University of Ostrava, 710 00 Ostrava, Czech Republic
| | - Petr Pečinka
- Department of Biology and Ecology, University of Ostrava, 710 00 Ostrava, Czech Republic
| | - Donna J Arndt-Jovin
- Emeritus Laboratory of Cellular Dynamics, Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany
| | - Thomas M Jovin
- Emeritus Laboratory of Cellular Dynamics, Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany
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2
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K G, Verma A, Mondal P, Mandal SS. Molecular contacts in the Cren7-DNA complex: A quantitative investigation for electrostatic interaction. Biophys J 2023; 122:1701-1719. [PMID: 37016575 PMCID: PMC10183371 DOI: 10.1016/j.bpj.2023.03.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 02/15/2023] [Accepted: 03/29/2023] [Indexed: 04/06/2023] Open
Abstract
The molecular association of proteins with nucleic acids leading to the formation of macromolecular complexes is a crucial step in several biological processes. Stabilization of these complexes involves electrostatic interactions between ion pairs (salt bridges) of nucleic acid phosphates and protein side chains. The crenarchaeal DNA binding protein, Cren7 plays a key role in the regulation of chromosomal structure and gene expression in eukaryotic extremophiles. However, the molecular contacts that occur at the interface of protein-DNA complexes and their contribution to the electrostatic interaction have not been fully elucidated. This work presents a quantitative description of the mechanism of the electrostatic interaction between the protein and DNA. We have identified a few residues located at the Cren7-DNA interface that could potentially be responsible for the interaction. Structural studies using circular dichroism indicate mutation of these surface residues minimally affect their structure and stability. The binding affinity of these mutants for the DNA duplexes was examined from reverse titration, biolayer interferometry, and fluorescence anisotropy measurements with calf thymus DNA, polynucleotides, and small DNA oligonucleotides. The resulting kinetic parameters highlight a difference in electrostatic interactions potentials exhibited by residues positioned at different locations of the protein-DNA interface. Computational studies attribute this difference to their surrounding atmosphere and energetic stabilization parameters. The biophysical approach described here can be extended for other proteins that play a crucial role in DNA bending and compaction, to properly evaluate the role of specific residues on the mechanisms of DNA binding.
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Affiliation(s)
- Geethika K
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, Andhra Pradesh, India
| | - Arunima Verma
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, Andhra Pradesh, India
| | - Padmabati Mondal
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, Andhra Pradesh, India.
| | - Soumit S Mandal
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, Andhra Pradesh, India.
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3
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Qin C, Lu YX, Borch T, Yang LL, Li YW, Zhao HM, Hu X, Gao Y, Xiang L, Mo CH, Li QX. Interactions between Extracellular DNA and Perfluoroalkyl Acids (PFAAs) Decrease the Bioavailability of PFAAs in Pakchoi ( Brassica chinensis L.). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:14622-14632. [PMID: 36375011 DOI: 10.1021/acs.jafc.2c04597] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Perfluoroalkyl acids (PFAAs) are emerging ionic organic pollutants worldwide. Great amounts of extracellular DNA (∼mg/kg) coexist with PFAAs in the environment. However, PFAA-DNA interactions and effects of such interactions have not been well studied. Herein, we used isothermal titration calorimetry (ITC), spectroscopy, and computational simulations to investigate the PFAA-DNA interactions. ITC assays showed that specific binding affinities of PFHxA-DNA, PFOA-DNA, PFNA-DNA, and PFOS-DNA were 5.14 × 105, 3.29 × 105, 1.99 × 105, and 2.18 × 104 L/mol, respectively, which were about 1-2 orders of magnitude stronger than those of PFAAs with human serum albumin. Spectral analysis suggested interactions of PFAAs with adenine (A), cytosine (C), guanine (G), and thymine (T), among which grooves associated with thymine were the major binding sites. Molecular dynamics simulations and quantum chemical calculations suggested that hydrogen bonds and van der Waals forces were the main interaction forces. Such a PFAA-DNA binding decreased the bioavailability of PFAAs in plant seedlings. The findings will help to improve the current understanding of the interaction between PFAAs and biomacromolecules, as well as how such interactions affect the bioavailability of PFAAs.
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Affiliation(s)
- Chao Qin
- Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, College of Life Science and Technology, Jinan University, Guangzhou510632, China
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing210095, China
| | - Ying-Xin Lu
- Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, College of Life Science and Technology, Jinan University, Guangzhou510632, China
| | - Thomas Borch
- Department of Chemistry, Colorado State University, 1872 Campus Delivery, Fort Collins, Colorado80523, United States
- Department of Soil and Crop Sciences, Colorado State University, 1170 Campus Delivery, Fort Collins, Colorado80523, United States
| | - Ling-Ling Yang
- Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, College of Life Science and Technology, Jinan University, Guangzhou510632, China
| | - Yan-Wen Li
- Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, College of Life Science and Technology, Jinan University, Guangzhou510632, China
| | - Hai-Ming Zhao
- Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, College of Life Science and Technology, Jinan University, Guangzhou510632, China
| | - Xiaojie Hu
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing210095, China
| | - Yanzheng Gao
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing210095, China
| | - Lei Xiang
- Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, College of Life Science and Technology, Jinan University, Guangzhou510632, China
| | - Ce-Hui Mo
- Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, College of Life Science and Technology, Jinan University, Guangzhou510632, China
| | - Qing X Li
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, Hawaii96822, United States
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4
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Gopan G, Ghaemi Z, Davis CM, Gruebele M. Spliceosomal SL1 RNA binding to U1-70K: the role of the extended RRM. Nucleic Acids Res 2022; 50:8193-8206. [PMID: 35876068 PMCID: PMC9371917 DOI: 10.1093/nar/gkac599] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 06/19/2022] [Accepted: 06/29/2022] [Indexed: 11/24/2022] Open
Abstract
The RNA recognition motif (RRM) occurs widely in RNA-binding proteins, but does not always by itself support full binding. For example, it is known that binding of SL1 RNA to the protein U1-70K in the U1 spliceosomal particle is reduced when a region flanking the RRM is truncated. How the RRM flanking regions that together with the RRM make up an ‘extended RRM’ (eRRM) contribute to complex stability and structural organization is unknown. We study the U1-70K eRRM bound to SL1 RNA by thermal dissociation and laser temperature jump kinetics; long-time molecular dynamics simulations interpret the experiments with atomistic resolution. Truncation of the helix flanking the RRM on its N-terminal side, ‘N-helix,’ strongly reduces overall binding, which is further weakened under higher salt and temperature conditions. Truncating the disordered region flanking the RRM on the C-terminal side, ‘C-IDR’, affects the local binding site. Surprisingly, all-atom simulations show that protein truncation enhances base stacking interactions in the binding site and leaves the overall number of hydrogen bonds intact. Instead, the flanking regions of the eRRM act in a distributed fashion via collective interactions with the RNA when external stresses such as temperature or high salt mimicking osmotic imbalance are applied.
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Affiliation(s)
- Gopika Gopan
- Department of Chemistry, University of Illinois, Urbana, IL 61801, USA
| | - Zhaleh Ghaemi
- Department of Chemistry, University of Illinois, Urbana, IL 61801, USA
| | - Caitlin M Davis
- Department of Chemistry, University of Illinois, Urbana, IL 61801, USA.,Department of Physics, University of Illinois, Urbana, IL 61801, USA
| | - Martin Gruebele
- Department of Chemistry, University of Illinois, Urbana, IL 61801, USA.,Department of Physics, University of Illinois, Urbana, IL 61801, USA.,Center for Biophysics and Quantitative Biology, University of Illinois, Urbana, IL 61801, USA
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5
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Jeronimo C, Robert F. The histone chaperone FACT: a guardian of chromatin structure integrity. Transcription 2022; 13:16-38. [PMID: 35485711 PMCID: PMC9467567 DOI: 10.1080/21541264.2022.2069995] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The identification of FACT as a histone chaperone enabling transcription through chromatin in vitro has strongly shaped how its roles are envisioned. However, FACT has been implicated in essentially all aspects of chromatin biology, from transcription to DNA replication, DNA repair, and chromosome segregation. In this review, we focus on recent literature describing the role and mechanisms of FACT during transcription. We highlight the prime importance of FACT in preserving chromatin integrity during transcription and challenge its role as an elongation factor. We also review evidence for FACT's role as a cell-type/gene-specificregulator of gene expression and briefly summarize current efforts at using FACT inhibition as an anti-cancerstrategy.
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Affiliation(s)
- Célia Jeronimo
- Institut de recherches cliniques de Montréal, Montréal, Québec, Canada
| | - François Robert
- Institut de recherches cliniques de Montréal, Montréal, Québec, Canada.,Département de Médecine, Faculté de Médecine, Université de Montréal, Montréal, Québec, Canada.,Faculty of Medicine, Division of Experimental Medicine, McGill University, Montréal, Québec, Canada
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6
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Yeou S, Lee NK. Single-Molecule Methods for Investigating the Double-Stranded DNA Bendability. Mol Cells 2022; 45:33-40. [PMID: 34470919 PMCID: PMC8819492 DOI: 10.14348/molcells.2021.0182] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 07/19/2021] [Accepted: 07/20/2021] [Indexed: 11/27/2022] Open
Abstract
The various DNA-protein interactions associated with the expression of genetic information involve double-stranded DNA (dsDNA) bending. Due to the importance of the formation of the dsDNA bending structure, dsDNA bending properties have long been investigated in the biophysics field. Conventionally, DNA bendability is characterized by innate averaging data from bulk experiments. The advent of single-molecule methods, such as atomic force microscopy, optical and magnetic tweezers, tethered particle motion, and single-molecule fluorescence resonance energy transfer measurement, has provided valuable tools to investigate not only the static structures but also the dynamic properties of bent dsDNA. Here, we reviewed the single-molecule methods that have been used for investigating dsDNA bendability and new findings related to dsDNA bending. Single-molecule approaches are promising tools for revealing the unknown properties of dsDNA related to its bending, particularly in cells.
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Affiliation(s)
- Sanghun Yeou
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Nam Ki Lee
- Department of Chemistry, Seoul National University, Seoul 08826, Korea
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7
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Tse DH, Becker NA, Young RT, Olson WK, Peters JP, Schwab TL, Clark KJ, Maher LJ. Designed architectural proteins that tune DNA looping in bacteria. Nucleic Acids Res 2021; 49:10382-10396. [PMID: 34478548 PMCID: PMC8501960 DOI: 10.1093/nar/gkab759] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/17/2021] [Accepted: 08/23/2021] [Indexed: 11/28/2022] Open
Abstract
Architectural proteins alter the shape of DNA. Some distort the double helix by introducing sharp kinks. This can serve to relieve strain in tightly-bent DNA structures. Here, we design and test artificial architectural proteins based on a sequence-specific Transcription Activator-like Effector (TALE) protein, either alone or fused to a eukaryotic high mobility group B (HMGB) DNA-bending domain. We hypothesized that TALE protein binding would stiffen DNA to bending and twisting, acting as an architectural protein that antagonizes the formation of small DNA loops. In contrast, fusion to an HMGB domain was hypothesized to generate a targeted DNA-bending architectural protein that facilitates DNA looping. We provide evidence from Escherichia coli Lac repressor gene regulatory loops supporting these hypotheses in living bacteria. Both data fitting to a thermodynamic DNA looping model and sophisticated molecular modeling support the interpretation of these results. We find that TALE protein binding inhibits looping by stiffening DNA to bending and twisting, while the Nhp6A domain enhances looping by bending DNA without introducing twisting flexibility. Our work illustrates artificial approaches to sculpt DNA geometry with functional consequences. Similar approaches may be applicable to tune the stability of small DNA loops in eukaryotes.
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Affiliation(s)
- David H Tse
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, 200 First St. SW, Rochester, MN 55905, USA
| | - Nicole A Becker
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, 200 First St. SW, Rochester, MN 55905, USA
| | - Robert T Young
- Department of Chemistry and Chemical Biology, Rutgers, the State University of New Jersey, Center for Quantitative Biology, Piscataway, NJ 08854, USA
| | - Wilma K Olson
- Department of Chemistry and Chemical Biology, Rutgers, the State University of New Jersey, Center for Quantitative Biology, Piscataway, NJ 08854, USA
| | - Justin P Peters
- Department of Chemistry and Biochemistry, University of Northern Iowa, 1227 West 27th Street, Cedar Falls, IA 50614, USA
| | - Tanya L Schwab
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, 200 First St. SW, Rochester, MN 55905, USA
| | - Karl J Clark
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, 200 First St. SW, Rochester, MN 55905, USA
| | - L James Maher
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, 200 First St. SW, Rochester, MN 55905, USA
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8
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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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9
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Yoshua SB, Watson GD, Howard JAL, Velasco-Berrelleza V, Leake MC, Noy A. Integration host factor bends and bridges DNA in a multiplicity of binding modes with varying specificity. Nucleic Acids Res 2021; 49:8684-8698. [PMID: 34352078 PMCID: PMC8421141 DOI: 10.1093/nar/gkab641] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 07/02/2021] [Accepted: 07/16/2021] [Indexed: 11/29/2022] Open
Abstract
Nucleoid-associated proteins (NAPs) are crucial in organizing prokaryotic DNA and regulating genes. Vital to these activities are complex nucleoprotein structures, however, how these form remains unclear. Integration host factor (IHF) is an Escherichia coli NAP that creates very sharp bends in DNA at sequences relevant to several functions including transcription and recombination, and is also responsible for general DNA compaction when bound non-specifically. We show that IHF–DNA structural multimodality is more elaborate than previously thought, and provide insights into how this drives mechanical switching towards strongly bent DNA. Using single-molecule atomic force microscopy and atomic molecular dynamics simulations we find three binding modes in roughly equal proportions: ‘associated’ (73° of DNA bend), ‘half-wrapped’ (107°) and ‘fully-wrapped’ (147°), only the latter occurring with sequence specificity. We show IHF bridges two DNA double helices through non-specific recognition that gives IHF a stoichiometry greater than one and enables DNA mesh assembly. We observe that IHF-DNA structural multiplicity is driven through non-specific electrostatic interactions that we anticipate to be a general NAP feature for physical organization of chromosomes.
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Affiliation(s)
- Samuel B Yoshua
- Department of Physics, University of York, York YO10 5DD, UK
| | - George D Watson
- Department of Physics, University of York, York YO10 5DD, UK
| | | | | | - Mark C Leake
- Department of Physics, University of York, York YO10 5DD, UK.,Department of Biology, University of York, York YO10 5DD, UK
| | - Agnes Noy
- Department of Physics, University of York, York YO10 5DD, UK
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10
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Formosa T, Winston F. The role of FACT in managing chromatin: disruption, assembly, or repair? Nucleic Acids Res 2020; 48:11929-11941. [PMID: 33104782 PMCID: PMC7708052 DOI: 10.1093/nar/gkaa912] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/01/2020] [Accepted: 10/05/2020] [Indexed: 12/20/2022] Open
Abstract
FACT (FAcilitates Chromatin Transcription) has long been considered to be a transcription elongation factor whose ability to destabilize nucleosomes promotes RNAPII progression on chromatin templates. However, this is just one function of this histone chaperone, as FACT also functions in DNA replication. While broadly conserved among eukaryotes and essential for viability in many organisms, dependence on FACT varies widely, with some differentiated cells proliferating normally in its absence. It is therefore unclear what the core functions of FACT are, whether they differ in different circumstances, and what makes FACT essential in some situations but not others. Here, we review recent advances and propose a unifying model for FACT activity. By analogy to DNA repair, we propose that the ability of FACT to both destabilize and assemble nucleosomes allows it to monitor and restore nucleosome integrity as part of a system of chromatin repair, in which disruptions in the packaging of DNA are sensed and returned to their normal state. The requirement for FACT then depends on the level of chromatin disruption occurring in the cell, and the cell's ability to tolerate packaging defects. The role of FACT in transcription would then be just one facet of a broader system for maintaining chromatin integrity.
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Affiliation(s)
- Tim Formosa
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Fred Winston
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
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11
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Kamagata K, Ouchi K, Tan C, Mano E, Mandali S, Wu Y, Takada S, Takahashi S, Johnson RC. The HMGB chromatin protein Nhp6A can bypass obstacles when traveling on DNA. Nucleic Acids Res 2020; 48:10820-10831. [PMID: 32997109 PMCID: PMC7641734 DOI: 10.1093/nar/gkaa799] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 08/13/2020] [Accepted: 09/15/2020] [Indexed: 12/16/2022] Open
Abstract
DNA binding proteins rapidly locate their specific DNA targets through a combination of 3D and 1D diffusion mechanisms, with the 1D search involving bidirectional sliding along DNA. However, even in nucleosome-free regions, chromosomes are highly decorated with associated proteins that may block sliding. Here we investigate the ability of the abundant chromatin-associated HMGB protein Nhp6A from Saccharomyces cerevisiae to travel along DNA in the presence of other architectural DNA binding proteins using single-molecule fluorescence microscopy. We observed that 1D diffusion by Nhp6A molecules is retarded by increasing densities of the bacterial proteins Fis and HU and by Nhp6A, indicating these structurally diverse proteins impede Nhp6A mobility on DNA. However, the average travel distances were larger than the average distances between neighboring proteins, implying Nhp6A is able to bypass each of these obstacles. Together with molecular dynamics simulations, our analyses suggest two binding modes: mobile molecules that can bypass barriers as they seek out DNA targets, and near stationary molecules that are associated with neighboring proteins or preferred DNA structures. The ability of mobile Nhp6A molecules to bypass different obstacles on DNA suggests they do not block 1D searches by other DNA binding proteins.
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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.,Graduate School of Life Sciences, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan.,Department of Chemistry, Faculty of Science, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
| | - Kana Ouchi
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan.,Graduate School of Life Sciences, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
| | - Cheng Tan
- Computational Biophysics Research Team, RIKEN Center for Computational Science, 7-1-26 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Eriko Mano
- 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
| | - Yining Wu
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan.,Department of Chemistry, Faculty of Science, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
| | - Shoji Takada
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Satoshi Takahashi
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan.,Graduate School of Life Sciences, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan.,Department of Chemistry, Faculty of Science, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, 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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12
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Qin C, Hu X, Waigi MG, Yang B, Gao Y. Amino and hydroxy substitution influences pyrene-DNA binding. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 725:138542. [PMID: 32304974 DOI: 10.1016/j.scitotenv.2020.138542] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 04/05/2020] [Accepted: 04/06/2020] [Indexed: 06/11/2023]
Abstract
Polycyclic aromatic hydrocarbon (PAH)-DNA binding is an essential step in PAH-induced carcinogenesis. A large number of PAHs contain substituents, it is unclear whether functional groups will influence the PAH-DNA binding. Here, we investigated amino (-NH2) and hydroxy (-OH) substitution on pyrene-DNA binding. Because of the considerable effects of electrostatic surface potential (ESP), -NH2 substitution significantly facilitated binding by increasing the binding constant (log KA) from 4.14 L mol-1 to 12.31 L mol-1, while -OH substitution inhibited binding by reducing log KA to 3.68 L mol-1. Spectroscopy results revealed that pyrene and its derivatives were able to bind with thymine to induce DNA damage or double helix distortion. Quantum chemical calculations showed that -NH2 substitution induces hydrogen bond formation, thereby enhancing the binding of pyrene with DNA; moreover, binding force changes due to -OH substitution may not be an essential factor. All structural descriptors were not correlated with the quenching constant (KSV) or binding constant, indicating that changes in physicochemical properties shows no influence on pyrene-DNA binding. The results of this study will improve our understanding of the contribution of functional groups to PAH-DNA binding.
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Affiliation(s)
- Chao Qin
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Xiaojie Hu
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Michael Gatheru Waigi
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Bing Yang
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Yanzheng Gao
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
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Panigrahi A, Vemuri H, Aggarwal M, Pitta K, Krishnan M. Sequence specificity, energetics and mechanism of mismatch recognition by DNA damage sensing protein Rad4/XPC. Nucleic Acids Res 2020; 48:2246-2257. [PMID: 32047903 PMCID: PMC7049735 DOI: 10.1093/nar/gkaa078] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 01/27/2020] [Accepted: 02/10/2020] [Indexed: 12/25/2022] Open
Abstract
The ultraviolet (UV) radiation-induced DNA lesions play a causal role in many prevalent genetic skin-related diseases and cancers. The damage sensing protein Rad4/XPC specifically recognizes and repairs these lesions with high fidelity and safeguards genome integrity. Despite considerable progress, the mechanistic details of the mode of action of Rad4/XPC in damage recognition remain obscure. The present study investigates the mechanism, energetics, dynamics, and the molecular basis for the sequence specificity of mismatch recognition by Rad4/XPC. We dissect the following three key molecular events that occur as Rad4/XPC tries to recognize and bind to DNA lesions/mismatches: (a) the association of Rad4/XPC with the damaged/mismatched DNA, (b) the insertion of a lesion-sensing β-hairpin of Rad4/XPC into the damage/mismatch site and (c) the flipping of a pair of nucleotide bases at the damage/mismatch site. Using suitable reaction coordinates, the free energy surfaces for these events are determined using molecular dynamics (MD) and umbrella sampling simulations on three mismatched (CCC/CCC, TTT/TTT and TAT/TAT mismatches) Rad4-DNA complexes. The study identifies the key determinants of the sequence-dependent specificity of Rad4 for the mismatches and explores the ramifications of specificity in the aforementioned events. The results unravel the molecular basis for the high specificity of Rad4 towards CCC/CCC mismatch and lower specificity for the TAT/TAT mismatch. A strong correlation between the depth of β-hairpin insertion into the DNA duplex and the degree of coupling between the hairpin insertion and the flipping of bases is also observed. The interplay of the conformational flexibility of mismatched bases, the depth of β-hairpin insertion, Rad4-DNA association energetics and the Rad4 specificity explored here complement recent experimental FRET studies on Rad4-DNA complexes.
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Affiliation(s)
- Abhinandan Panigrahi
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology, Gachibowli, Hyderabad, Telangana 500032, India
| | - Hemanth Vemuri
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology, Gachibowli, Hyderabad, Telangana 500032, India
| | - Madhur Aggarwal
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology, Gachibowli, Hyderabad, Telangana 500032, India
| | - Kartheek Pitta
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology, Gachibowli, Hyderabad, Telangana 500032, India
| | - Marimuthu Krishnan
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology, Gachibowli, Hyderabad, Telangana 500032, India
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14
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Ding L, Wu Y, Liu W, Liu L, Yu F, Yu S, Tian Y, Feng J, He L. Magnetic-assisted self-assembled aptamer/protein hybrid probes for efficient capture and rapid detection of cancer cells in whole blood. Talanta 2019; 205:120129. [PMID: 31450438 DOI: 10.1016/j.talanta.2019.120129] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 06/26/2019] [Accepted: 07/08/2019] [Indexed: 12/17/2022]
Abstract
Self-assembly of building blocks for constructing multifunctional materials has opened prospects for sensing applications in the biomedical fields. In particular, the combination of aptamer with DNA assembly-based nanotechnology has greatly improved the performance of cancer cell detection. Nevertheless, the cancer cell detection strategies of integrating aptamer with protein are relatively sparse. So we have developed a self-assembled aptamer method to realize the efficient capture and rapid detection of cancer cells by ingeniously combining aptamer modified magnetic nanoparticles as capture nanoprobes with self-assembled aptamer/protein hybrid probes (SAPPs) as signal amplification probes. By merely mixing the component materials together simultaneously, the SAPPs, integrating aptamer for cancer cell recognition with protein for amplifying signal, were fabricated by DNA-governed one-step assembly. In addition, the SAPPs-based method exhibits efficient capture, rapid (about 45 min) and specific CCRF-CEM detection performance, with limits of detection down to 75 cells/mL in buffer and 200 cells/mL in whole blood.
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Affiliation(s)
- Lihua Ding
- College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Yongjun Wu
- College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Wei Liu
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450001, China
| | - Lie Liu
- College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Fei Yu
- College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Songcheng Yu
- College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Yongmei Tian
- College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Jiaodi Feng
- College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou, 450001, China
| | - Leiliang He
- College of Public Health, Zhengzhou University, Zhengzhou, 450001, China.
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