1
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Zhao L, Cheng L, Yang Y, Wang P, Tian P, Yang T, Nian H, Cao L. Biomimetic Hydrogen-Bonded G ⋅ C ⋅ G ⋅ C Quadruplex within a Tetraphenylethene-Based Octacationic Spirobicycle in Water. Angew Chem Int Ed Engl 2024; 63:e202405150. [PMID: 38591857 DOI: 10.1002/anie.202405150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 04/01/2024] [Accepted: 04/09/2024] [Indexed: 04/10/2024]
Abstract
In biological systems, nucleotide quadruplexes (such as G-quadruplexes) in DNA and RNA that are held together by multiple hydrogen bonds play a crucial functional role. The biomimetic formation of these hydrogen-bonded quadruplexes captured by artificial systems in water poses a significant challenge but can offer valuable insights into these complex functional structures. Herein, we report the formation of biomimetic hydrogen-bonded G ⋅ C ⋅ G ⋅ C quadruplex captured by a tetraphenylethene (TPE) based octacationic spirobicycle (1). The spirobicyclic compound possesses a three-dimensional (3D) crossing dual-cavity structure, which enables the encapsulation of four d(GpC) dinucleotide molecules, thereby realizing 1 : 4 host-guest complexation in water. The X-ray structure reveals that four d(GpC) molecules further form a two-layer G ⋅ C ⋅ G ⋅ C quadruplex with Watson-Crick hydrogen bonds, which are stabilized within the dual hydrophobic cavities of 1 through the cooperative non-covalent interactions of hydrogen bonds, CH⋅⋅⋅π interactions, and hydrophobic effect. Due to the dynamically-rotational propeller chirality of TPE units, 1 with adaptive chirality can further serve as a chiroptical sensor to exhibit opposite Cotton effects with mirror-image CD spectra for the pH-dependent hydrogen-bonded assemblies of d(GpC) including the Watson-Crick G ⋅ C ⋅ G ⋅ C (pH 9.22) and Hoogsteen G ⋅ C+ ⋅ G ⋅ C+ (pH 5.74) quartets through the host-guest chirality transfer in water.
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Affiliation(s)
- Lingyu Zhao
- College of Chemistry and Materials Science, Northwest University, Xi'an, 710069, P. R. China)
| | - Lin Cheng
- College of Chemistry and Materials Science, Northwest University, Xi'an, 710069, P. R. China)
| | - Yanxia Yang
- College of Chemistry and Materials Science, Northwest University, Xi'an, 710069, P. R. China)
| | - Pingxia Wang
- College of Chemistry and Materials Science, Northwest University, Xi'an, 710069, P. R. China)
| | - Ping Tian
- College of Chemistry and Materials Science, Northwest University, Xi'an, 710069, P. R. China)
| | - Ting Yang
- College of Chemistry and Materials Science, Northwest University, Xi'an, 710069, P. R. China)
| | - Hao Nian
- College of Chemistry and Materials Science, Northwest University, Xi'an, 710069, P. R. China)
| | - Liping Cao
- College of Chemistry and Materials Science, Northwest University, Xi'an, 710069, P. R. China)
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2
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Meng J, Shen H, Luo L, Zeng X, Wang J, Liu Y, Xu ZL. Engineered DNAzyme Enables Homogeneous Detection of Cereulide via Polychromic Fluorescence Modality. Anal Chem 2023; 95:14135-14142. [PMID: 37669908 DOI: 10.1021/acs.analchem.3c03166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2023]
Abstract
Cereulide, the exotoxin of emetic Bacillus cereus, has garnered considerable attention due to its capacity to produce foodborne poisonings and great chemical stability. Herein, a G-quadruplex-hemin DNAzyme-based biosensor was developed to detect cereulide in the homogeneous solution. Due to the special ring structure and high affinity to K+, cereulide can be attracted and intercalated into the G-quadruplex; thus, the properties of the G4 DNAzyme can be altered. The melting temperature (Tm) of the G4 DNAzyme in the presence or absence of cereulide was 58.75 and 50.10 °C, respectively, proving the intercalation of cereulide into the G4 DNAzyme. By using the polychromic fluorescence modality of CdTe quantum dots and o-phenylenediamine to assess the variation in the catalytic activity of the DNAzyme, the intercalation of cereulide had bidirectional effects in G4 DNAzyme-mediated reactions, showing that the fluorescence intensity of CdTe quantum dots displayed a linear relationship with the concentration of cereulide from 0.16 to 40 μg/mL with the limit of detection (LOD) of 0.10 μg/mL, while the fluorescence intensity of DAP exhibited a linear relationship with the concentration of cereulide from 0.02 to 40 μg/mL with the LOD of 0.01 μg/mL. It will be a perspective step of controlling cereulide as a hazardous material in food or the environment.
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Affiliation(s)
- Jingnan Meng
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China
- Key Laboratory for Biobased Materials and Energy of Ministry of Education, College of Materials and Energy, South China Agricultural University, Guangzhou 510642, China
- College of Food Engineering, Anhui Science and Technology University, Chuzhou 233100, China
| | - Haoran Shen
- Key Laboratory for Biobased Materials and Energy of Ministry of Education, College of Materials and Energy, South China Agricultural University, Guangzhou 510642, China
| | - Lin Luo
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China
| | - Xi Zeng
- Guangzhou Institute of Food Inspection, Guangzhou 510410, China
| | - Juan Wang
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China
| | - Yingju Liu
- Key Laboratory for Biobased Materials and Energy of Ministry of Education, College of Materials and Energy, South China Agricultural University, Guangzhou 510642, China
| | - Zhen-Lin Xu
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China
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3
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Pereira HS, Gemmill DL, Siddiqui MQ, Vasudeva G, Patel TR. Mapping and characterization of G-quadruplexes in monkeypox genomes. J Med Virol 2023; 95:e28783. [PMID: 37212309 DOI: 10.1002/jmv.28783] [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] [Received: 10/04/2022] [Revised: 04/19/2023] [Accepted: 04/22/2023] [Indexed: 05/23/2023]
Abstract
Monkeypox virus (MPXV) is a double-stranded DNA virus from the family Poxviridae, which is endemic in West and Central Africa. Various human outbreaks occurred in the 1980s, resulting from a cessation of smallpox vaccination. Recently, MPXV cases have reemerged in non-endemic nations, and the 2022 outbreak has been declared a public health emergency. Treatment optionsare limited, and many countries lack the infrastructure to provide symptomatic treatments. The development of cost-effective antivirals could ease severe health outcomes. G-quadruplexes have been a target of interest in treating viral infections with different chemicals. In the present work, a genomic-scale mapping of different MPXV isolates highlighted two conserved putative quadruplex-forming sequences MPXV-exclusive in 590 isolates. Subsequently, we assessed the G-quadruplex formation using circular dichroism spectroscopy and solution small-angle X-ray scattering. Furthermore, biochemical assays indicated the ability of MPXV quadruplexes to be recognized by two specific G4-binding partners-Thioflavin T and DHX36. Additionally, our work also suggests that a quadruplex binding small-molecule with previously reported antiviral activity, TMPyP4, interacts with MPXV G-quadruplexes with nanomolar affinity in the presence and absence of DHX36. Finally, cell biology experiments suggests that TMPyP4 treatment substantially reduced gene expression of MPXV proteins. In summary, our work provides insights into the G-quadruplexes from the MPXV genome that can be further exploited to develop therapeutics.
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Affiliation(s)
- Higor Sette Pereira
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Darren L Gemmill
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, Lethbridge, Alberta, Canada
| | - M Quadir Siddiqui
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Gunjan Vasudeva
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Trushar R Patel
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, Lethbridge, Alberta, Canada
- Department of Microbiology, Immunology and Infectious Disease, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alberta, Canada
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4
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Meier M, Gupta M, Akgül S, McDougall M, Imhof T, Nikodemus D, Reuten R, Moya-Torres A, To V, Ferens F, Heide F, Padilla-Meier GP, Kukura P, Huang W, Gerisch B, Mörgelin M, Poole K, Antebi A, Koch M, Stetefeld J. The dynamic nature of netrin-1 and the structural basis for glycosaminoglycan fragment-induced filament formation. Nat Commun 2023; 14:1226. [PMID: 36869049 PMCID: PMC9984387 DOI: 10.1038/s41467-023-36692-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 02/13/2023] [Indexed: 03/05/2023] Open
Abstract
Netrin-1 is a bifunctional chemotropic guidance cue that plays key roles in diverse cellular processes including axon pathfinding, cell migration, adhesion, differentiation, and survival. Here, we present a molecular understanding of netrin-1 mediated interactions with glycosaminoglycan chains of diverse heparan sulfate proteoglycans (HSPGs) and short heparin oligosaccharides. Whereas interactions with HSPGs act as platform to co-localise netrin-1 close to the cell surface, heparin oligosaccharides have a significant impact on the highly dynamic behaviour of netrin-1. Remarkably, the monomer-dimer equilibrium of netrin-1 in solution is abolished in the presence of heparin oligosaccharides and replaced with highly hierarchical and distinct super assemblies leading to unique, yet unknown netrin-1 filament formation. In our integrated approach we provide a molecular mechanism for the filament assembly which opens fresh paths towards a molecular understanding of netrin-1 functions.
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Affiliation(s)
- Markus Meier
- Department of Chemistry, University of Manitoba, Winnipeg, Canada
| | - Monika Gupta
- Department of Chemistry, University of Manitoba, Winnipeg, Canada
| | - Serife Akgül
- Center for Biochemistry II, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931, Cologne, Germany.,Max Planck Institute for Biology of Ageing, Cologne, Germany
| | | | - Thomas Imhof
- Center for Biochemistry II, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931, Cologne, Germany
| | - Denise Nikodemus
- Faculty of Biology, Institute of Biology II, Albert Ludwigs University of Freiburg, Freiburg, Germany
| | - Raphael Reuten
- Institute of Experimental and Clinical Pharmacology and Toxicology, Medical Faculty, University of Freiburg, Freiburg, Germany.,Department of Obsterics and Gynecology, Medical Center, University of Freiburg, Freiburg, Germany
| | | | - Vu To
- Department of Chemistry, University of Manitoba, Winnipeg, Canada
| | - Fraser Ferens
- Department of Chemistry, University of Manitoba, Winnipeg, Canada
| | - Fabian Heide
- Department of Chemistry, University of Manitoba, Winnipeg, Canada
| | | | - Philipp Kukura
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK
| | - Wenming Huang
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Birgit Gerisch
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | | | - Kate Poole
- Max Delbrück Center for Molecular Medicine, Robert Roessle Str 10, Berlin-Buch, Germany.,EMBL Australia Node in Single Molecule Science, School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Adam Antebi
- Max Planck Institute for Biology of Ageing, Cologne, Germany. .,Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases, University of Cologne, Cologne, 50931, Germany.
| | - Manuel Koch
- Center for Biochemistry II, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931, Cologne, Germany. .,Institute for Dental Research and Oral Musculoskeletal Biology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931, Cologne, Germany. .,Center for Molecular Medicine Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931, Cologne, Germany.
| | - Jörg Stetefeld
- Department of Chemistry, University of Manitoba, Winnipeg, Canada.
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5
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Zegers J, Peters M, Albada B. DNA G-quadruplex-stabilizing metal complexes as anticancer drugs. J Biol Inorg Chem 2023; 28:117-138. [PMID: 36456886 PMCID: PMC9981530 DOI: 10.1007/s00775-022-01973-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 11/17/2022] [Indexed: 12/04/2022]
Abstract
Guanine quadruplexes (G4s) are important targets for cancer treatments as their stabilization has been associated with a reduction of telomere ends or a lower oncogene expression. Although less abundant than purely organic ligands, metal complexes have shown remarkable abilities to stabilize G4s, and a wide variety of techniques have been used to characterize the interaction between ligands and G4s. However, improper alignment between the large variety of experimental techniques and biological activities can lead to improper identification of top candidates, which hampers progress of this important class of G4 stabilizers. To address this, we first review the different techniques for their strengths and weaknesses to determine the interaction of the complexes with G4s, and provide a checklist to guide future developments towards comparable data. Then, we surveyed 74 metal-based ligands for G4s that have been characterized to the in vitro level. Of these complexes, we assessed which methods were used to characterize their G4-stabilizing capacity, their selectivity for G4s over double-stranded DNA (dsDNA), and how this correlated to bioactivity data. For the biological activity data, we compared activities of the G4-stabilizing metal complexes with that of cisplatin. Lastly, we formulated guidelines for future studies on G4-stabilizing metal complexes to further enable maturation of this field.
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Affiliation(s)
- Jaccoline Zegers
- grid.4818.50000 0001 0791 5666Laboratory of Organic Chemistry, Wageningen University and Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Maartje Peters
- grid.4818.50000 0001 0791 5666Laboratory of Organic Chemistry, Wageningen University and Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Bauke Albada
- Laboratory of Organic Chemistry, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.
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6
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Tersteeg S, Mrozowich T, Henrickson A, Demeler B, Patel TR. Purification and characterization of inorganic pyrophosphatase for in vitro RNA transcription. Biochem Cell Biol 2022; 100:425-436. [PMID: 35926232 PMCID: PMC10311840 DOI: 10.1139/bcb-2022-0118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Inorganic pyrophosphatase (iPPase) is an enzyme that cleaves pyrophosphate into two phosphate molecules. This enzyme is an essential component of in vitro transcription (IVT) reactions for RNA preparation as it prevents pyrophosphate from precipitating with magnesium, ultimately increasing the rate of the IVT reaction. Large-scale RNA production is often required for biochemical and biophysical characterization studies of RNA, therefore requiring large amounts of IVT reagents. Commercially purchased iPPase is often the most expensive component of any IVT reaction. In this paper, we demonstrate that iPPase can be produced in large quantities and high quality using a reasonably generic laboratory facility and that laboratory-purified iPPase is as effective as commercially available iPPase. Furthermore, using size exclusion chromatography coupled with multi-angle light scattering and dynamic light scattering, analytical ultracentrifugation, and small-angle X-ray scattering, we demonstrate that yeast iPPase can form tetramers and hexamers in solution as well as the enzymatically active dimer. Our work provides a robust protocol for laboratories involved with RNA in vitro transcription to efficiently produce active iPPase, significantly reducing the financial strain of large-scale RNA production.
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Affiliation(s)
- Scott Tersteeg
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada
| | - Tyler Mrozowich
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada
| | - Amy Henrickson
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada
| | - Borries Demeler
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada
- Department of Chemistry and Biochemistry, University of Montana, Missoula, MT 59812, USA
| | - Trushar R. Patel
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada
- Li Ka Shing Institute of Virology, University of Alberta, Edmonton, AB T6G 2E1, Canada
- Department of Microbiology, Immunology & Infectious Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
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7
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Mellor C, Perez C, Sale JE. Creation and resolution of non-B-DNA structural impediments during replication. Crit Rev Biochem Mol Biol 2022; 57:412-442. [PMID: 36170051 PMCID: PMC7613824 DOI: 10.1080/10409238.2022.2121803] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 08/02/2022] [Accepted: 08/25/2022] [Indexed: 01/27/2023]
Abstract
During replication, folding of the DNA template into non-B-form secondary structures provides one of the most abundant impediments to the smooth progression of the replisome. The core replisome collaborates with multiple accessory factors to ensure timely and accurate duplication of the genome and epigenome. Here, we discuss the forces that drive non-B structure formation and the evidence that secondary structures are a significant and frequent source of replication stress that must be actively countered. Taking advantage of recent advances in the molecular and structural biology of the yeast and human replisomes, we examine how structures form and how they may be sensed and resolved during replication.
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Affiliation(s)
- Christopher Mellor
- Division of Protein & Nucleic Acid Chemistry, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Consuelo Perez
- Division of Protein & Nucleic Acid Chemistry, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Julian E Sale
- Division of Protein & Nucleic Acid Chemistry, MRC Laboratory of Molecular Biology, Cambridge, UK
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8
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Monsen RC, DeLeeuw LW, Dean W, Gray R, Chakravarthy S, Hopkins J, Chaires J, Trent J. Long promoter sequences form higher-order G-quadruplexes: an integrative structural biology study of c-Myc, k-Ras and c-Kit promoter sequences. Nucleic Acids Res 2022; 50:4127-4147. [PMID: 35325198 PMCID: PMC9023277 DOI: 10.1093/nar/gkac182] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/03/2022] [Accepted: 03/21/2022] [Indexed: 12/15/2022] Open
Abstract
We report on higher-order G-quadruplex structures adopted by long promoter sequences obtained by an iterative integrated structural biology approach. Our approach uses quantitative biophysical tools (analytical ultracentrifugation, small-angle X-ray scattering, and circular dichroism spectroscopy) combined with modeling and molecular dynamics simulations, to derive self-consistent structural models. The formal resolution of our approach is 18 angstroms, but in some cases structural features of only a few nucleotides can be discerned. We report here five structures of long (34-70 nt) wild-type sequences selected from three cancer-related promoters: c-Myc, c-Kit and k-Ras. Each sequence studied has a unique structure. Three sequences form structures with two contiguous, stacked, G-quadruplex units. One longer sequence from c-Myc forms a structure with three contiguous stacked quadruplexes. A longer c-Kit sequence forms a quadruplex-hairpin structure. Each structure exhibits interfacial regions between stacked quadruplexes or novel loop geometries that are possible druggable targets. We also report methodological advances in our integrated structural biology approach, which now includes quantitative CD for counting stacked G-tetrads, DNaseI cleavage for hairpin detection and SAXS model refinement. Our results suggest that higher-order quadruplex assemblies may be a common feature within the genome, rather than simple single quadruplex structures.
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Affiliation(s)
- Robert C Monsen
- UofL Health Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA
| | - Lynn W DeLeeuw
- UofL Health Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA
| | - William L Dean
- UofL Health Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA
| | - Robert D Gray
- UofL Health Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA
| | - Srinivas Chakravarthy
- The Biophysics Collaborative Access Team (BioCAT), Department of Biological, Chemical, and Physical Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Jesse B Hopkins
- The Biophysics Collaborative Access Team (BioCAT), Department of Biological, Chemical, and Physical Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Jonathan B Chaires
- UofL Health Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA
- Department of Medicine, University of Louisville, Louisville, KY 40202, USA
- Department of Biochemistry and Molecular Genetics, University of Louisville, Louisville, KY 40202, USA
| | - John O Trent
- UofL Health Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA
- Department of Medicine, University of Louisville, Louisville, KY 40202, USA
- Department of Biochemistry and Molecular Genetics, University of Louisville, Louisville, KY 40202, USA
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9
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de Vries I, Kwakman T, Lu XJ, Hekkelman ML, Deshpande M, Velankar S, Perrakis A, Joosten RP. New restraints and validation approaches for nucleic acid structures in PDB-REDO. Acta Crystallogr D Struct Biol 2021; 77:1127-1141. [PMID: 34473084 PMCID: PMC8411979 DOI: 10.1107/s2059798321007610] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 07/26/2021] [Indexed: 11/10/2022] Open
Abstract
The quality of macromolecular structure models crucially depends on refinement and validation targets, which optimally describe the expected chemistry. Commonly used software for these two procedures has been designed and developed in a protein-centric manner, resulting in relatively few established features for the refinement and validation of nucleic acid-containing structure models. Here, new nucleic acid-specific approaches implemented in PDB-REDO are described, including a new restraint model using noncovalent geometries (base-pair hydrogen bonding and base-pair stacking) as refinement targets. New validation routines are also presented, including a metric for Watson-Crick base-pair geometry normality (ZbpG). Applying the PDB-REDO pipeline with the new restraint model to the whole Protein Data Bank (PDB) demonstrates an overall positive effect on the quality of nucleic acid-containing structure models. Finally, we discuss examples of improvements in the geometry of specific nucleic acid structures in the PDB. The new PDB-REDO models and pipeline are available at https://pdb-redo.eu/.
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Affiliation(s)
- Ida de Vries
- Oncode Institute and Division of Biochemistry, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Tim Kwakman
- Oncode Institute and Division of Biochemistry, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Xiang-Jun Lu
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Maarten L. Hekkelman
- Oncode Institute and Division of Biochemistry, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Mandar Deshpande
- Protein Data Bank in Europe (PDBe), European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL–EBI), Wellcome Genome Campus, Hinxton CB10 1SD, United Kingdom
| | - Sameer Velankar
- Protein Data Bank in Europe (PDBe), European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL–EBI), Wellcome Genome Campus, Hinxton CB10 1SD, United Kingdom
| | - Anastassis Perrakis
- Oncode Institute and Division of Biochemistry, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Robbie P. Joosten
- Oncode Institute and Division of Biochemistry, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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10
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Santos T, Salgado GF, Cabrita EJ, Cruz C. G-Quadruplexes and Their Ligands: Biophysical Methods to Unravel G-Quadruplex/Ligand Interactions. Pharmaceuticals (Basel) 2021; 14:769. [PMID: 34451866 PMCID: PMC8401999 DOI: 10.3390/ph14080769] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 07/31/2021] [Accepted: 08/03/2021] [Indexed: 12/12/2022] Open
Abstract
Progress in the design of G-quadruplex (G4) binding ligands relies on the availability of approaches that assess the binding mode and nature of the interactions between G4 forming sequences and their putative ligands. The experimental approaches used to characterize G4/ligand interactions can be categorized into structure-based methods (circular dichroism (CD), nuclear magnetic resonance (NMR) spectroscopy and X-ray crystallography), affinity and apparent affinity-based methods (surface plasmon resonance (SPR), isothermal titration calorimetry (ITC) and mass spectrometry (MS)), and high-throughput methods (fluorescence resonance energy transfer (FRET)-melting, G4-fluorescent intercalator displacement assay (G4-FID), affinity chromatography and microarrays. Each method has unique advantages and drawbacks, which makes it essential to select the ideal strategies for the biological question being addressed. The structural- and affinity and apparent affinity-based methods are in several cases complex and/or time-consuming and can be combined with fast and cheap high-throughput approaches to improve the design and development of new potential G4 ligands. In recent years, the joint use of these techniques permitted the discovery of a huge number of G4 ligands investigated for diagnostic and therapeutic purposes. Overall, this review article highlights in detail the most commonly used approaches to characterize the G4/ligand interactions, as well as the applications and types of information that can be obtained from the use of each technique.
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Affiliation(s)
- Tiago Santos
- CICS-UBI—Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal;
| | - Gilmar F. Salgado
- ARNA Laboratory, Université de Bordeaux, Inserm U1212, CNRS UMR 5320, IECB, 33607 Pessac, France;
| | - Eurico J. Cabrita
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal;
- Associate Laboratory i4HB—Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal
| | - Carla Cruz
- CICS-UBI—Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal;
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11
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González-Jiménez M, Ramakrishnan G, Tukachev NV, Senn HM, Wynne K. Low-frequency vibrational modes in G-quadruplexes reveal the mechanical properties of nucleic acids. Phys Chem Chem Phys 2021; 23:13250-13260. [PMID: 34095914 PMCID: PMC8207511 DOI: 10.1039/d0cp05404f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Low-frequency vibrations play an essential role in biomolecular processes involving DNA such as gene expression, charge transfer, drug intercalation, and DNA–protein recognition. However, understanding the vibrational basis of these mechanisms relies on theoretical models due to the lack of experimental evidence. Here we present the low-frequency vibrational spectra of G-quadruplexes (structures formed by four strands of DNA) and B-DNA characterized using femtosecond optical Kerr-effect spectroscopy. Contrary to expectation, we found that G-quadruplexes show several strongly underdamped delocalized phonon-like modes that have the potential to contribute to the biology of the DNA at the atomic level. In addition, G-quadruplexes present modes at a higher frequency than B-DNA demonstrating that changes in the stiffness of the molecule alter its gigahertz to terahertz vibrational profile. Low-frequency vibrations play an essential role in biomolecular processes involving DNA such as gene expression, charge transfer, drug intercalation, and DNA–protein recognition.![]()
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12
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Banco MT, Ferré-D'Amaré AR. The emerging structural complexity of G-quadruplex RNAs. RNA (NEW YORK, N.Y.) 2021; 27:390-402. [PMID: 33483368 PMCID: PMC7962482 DOI: 10.1261/rna.078238.120] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
G-quadruplexes (G4s) are four-stranded nucleic acid structures that arise from the stacking of G-quartets, cyclic arrangements of four guanines engaged in Hoogsteen base-pairing. Until recently, most RNA G4 structures were thought to conform to a sequence pattern in which guanines stacking within the G4 would also be contiguous in sequence (e.g., four successive guanine trinucleotide tracts separated by loop nucleotides). Such a sequence restriction, and the stereochemical constraints inherent to RNA (arising, in particular, from the presence of the 2'-OH), dictate relatively simple RNA G4 structures. Recent crystallographic and solution NMR structure determinations of a number of in vitro selected RNA aptamers have revealed RNA G4 structures of unprecedented complexity. Structures of the Sc1 aptamer that binds an RGG peptide from the Fragile-X mental retardation protein, various fluorescence turn-on aptamers (Corn, Mango, and Spinach), and the spiegelmer that binds the complement protein C5a, in particular, reveal complexity hitherto unsuspected in RNA G4s, including nucleotides in syn conformation, locally inverted strand polarity, and nucleotide quartets that are not all-G. Common to these new structures, the sequences folding into G4s do not conform to the requirement that guanine stacks arise from consecutive (contiguous in sequence) nucleotides. This review highlights how emancipation from this constraint drastically expands the structural possibilities of RNA G-quadruplexes.
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Affiliation(s)
- Michael T Banco
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, Bethesda, Maryland 20892-8012, USA
| | - Adrian R Ferré-D'Amaré
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, Bethesda, Maryland 20892-8012, USA
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13
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Jana J, Mohr S, Vianney YM, Weisz K. Structural motifs and intramolecular interactions in non-canonical G-quadruplexes. RSC Chem Biol 2021; 2:338-353. [PMID: 34458788 PMCID: PMC8341446 DOI: 10.1039/d0cb00211a] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 01/14/2021] [Indexed: 12/12/2022] Open
Abstract
Guanine(G)-rich DNA or RNA sequences can assemble or intramolecularly fold into G-quadruplexes formed through the stacking of planar G·G·G·G tetrads in the presence of monovalent cations. These secondary nucleic acid structures have convincingly been shown to also exist within a cellular environment exerting important regulatory functions in physiological processes. For identifying nucleic acid segments prone to quadruplex formation, a putative quadruplex sequence motif encompassing closely spaced tracts of three or more guanosines is frequently employed for bioinformatic search algorithms. Depending on the number and type of intervening residues as well as on solution conditions, such sequences may fold into various canonical G4 topologies with continuous G-columns. On the other hand, a growing number of sequences capable of quadruplex formation feature G-deficient guanine tracts, escaping the conservative consensus motif. By folding into non-canonical quadruplex structures, they adopt unique topologies depending on their specific sequence context. These include G-columns with only two guanines, bulges, snapback loops, D- and V-shaped loops as well as interlocked structures. This review focuses on G-quadruplex species carrying such distinct structural motifs. It evaluates characteristic features of their non-conventional scaffold and highlights principles of stabilizing interactions that also allow for their folding into stable G-quadruplex structures.
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Affiliation(s)
- Jagannath Jana
- Institute of Biochemistry, Universität Greifswald Felix-Hausdorff-Str. 4 D-17487 Greifswald Germany +49 3834 420-4427 +49 3834 420-4426
| | - Swantje Mohr
- Institute of Biochemistry, Universität Greifswald Felix-Hausdorff-Str. 4 D-17487 Greifswald Germany +49 3834 420-4427 +49 3834 420-4426
| | - Yoanes Maria Vianney
- Institute of Biochemistry, Universität Greifswald Felix-Hausdorff-Str. 4 D-17487 Greifswald Germany +49 3834 420-4427 +49 3834 420-4426
| | - Klaus Weisz
- Institute of Biochemistry, Universität Greifswald Felix-Hausdorff-Str. 4 D-17487 Greifswald Germany +49 3834 420-4427 +49 3834 420-4426
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14
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Das P, Ngo KH, Winnerdy FR, Maity A, Bakalar B, Mechulam Y, Schmitt E, Phan AT. Bulges in left-handed G-quadruplexes. Nucleic Acids Res 2021; 49:1724-1736. [PMID: 33503265 PMCID: PMC7897477 DOI: 10.1093/nar/gkaa1259] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/10/2020] [Accepted: 12/18/2020] [Indexed: 12/03/2022] Open
Abstract
G-quadruplex (G4) DNA structures with a left-handed backbone progression have unique and conserved structural features. Studies on sequence dependency of the structures revealed the prerequisites and some minimal motifs required for left-handed G4 formation. To extend the boundaries, we explore the adaptability of left-handed G4s towards the existence of bulges. Here we present two X-ray crystal structures and an NMR solution structure of left-handed G4s accommodating one, two and three bulges. Bulges in left-handed G4s show distinct characteristics as compared to those in right-handed G4s. The elucidation of intricate structural details will help in understanding the possible roles and limitations of these unique structures.
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Affiliation(s)
- Poulomi Das
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Khac Huy Ngo
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Fernaldo Richtia Winnerdy
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Arijit Maity
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Blaž Bakalar
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Yves Mechulam
- Laboratoire de Biologie Structurale de la Cellule (BIOC), Ecole Polytechnique, CNRS-UMR7654, Institut Polytechnique de Paris, Palaiseau 91128, France
| | - Emmanuelle Schmitt
- Laboratoire de Biologie Structurale de la Cellule (BIOC), Ecole Polytechnique, CNRS-UMR7654, Institut Polytechnique de Paris, Palaiseau 91128, France
| | - Anh Tuân Phan
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.,NTU Institute of Structural Biology, Nanyang Technological University, Singapore 636921, Singapore
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15
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Meier-Stephenson V, Badmalia MD, Mrozowich T, Lau KCK, Schultz SK, Gemmill DL, Osiowy C, van Marle G, Coffin CS, Patel TR. Identification and characterization of a G-quadruplex structure in the pre-core promoter region of hepatitis B virus covalently closed circular DNA. J Biol Chem 2021; 296:100589. [PMID: 33774051 PMCID: PMC8094906 DOI: 10.1016/j.jbc.2021.100589] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 03/17/2021] [Accepted: 03/23/2021] [Indexed: 02/07/2023] Open
Abstract
Approximately 250 million people worldwide are chronically infected with the hepatitis B virus (HBV) and are at increased risk of developing cirrhosis and hepatocellular carcinoma. The HBV genome persists as covalently closed circular DNA (cccDNA), which serves as the template for all HBV mRNA transcripts. Current nucleos(t)ide analogs used to treat HBV do not directly target the HBV cccDNA genome and thus cannot eradicate HBV infection. Here, we report the discovery of a unique G-quadruplex structure in the pre-core promoter region of the HBV genome that is conserved among nearly all genotypes. This region is central to critical steps in the viral life cycle, including the generation of pregenomic RNA, synthesis of core and polymerase proteins, and genome encapsidation; thus, an increased understanding of the HBV pre-core region may lead to the identification of novel anti-HBV cccDNA targets. We utilized biophysical methods (circular dichroism and small-angle X-ray scattering) to characterize the HBV G-quadruplex and the effect of three distinct G to A mutants. We also used microscale thermophoresis to quantify the binding affinity of G-quadruplex and its mutants with a known quadruplex-binding protein (DHX36). To investigate the physiological relevance of HBV G-quadruplex, we employed assays using DHX36 to pull-down cccDNA and compared HBV infection in HepG2 cells transfected with wild-type and mutant HBV plasmids by monitoring the levels of genomic DNA, pregenomic RNA, and antigens. Further evaluation of this critical host-protein interaction site in the HBV cccDNA genome may facilitate the development of novel anti-HBV therapeutics against the resilient cccDNA template.
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Affiliation(s)
- Vanessa Meier-Stephenson
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada; Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, University of Calgary, Alberta, Canada; Department of Medicine, Cumming School of Medicine, Calgary, Alberta, Canada
| | - Maulik D Badmalia
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Tyler Mrozowich
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Keith C K Lau
- Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, University of Calgary, Alberta, Canada
| | - Sarah K Schultz
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Darren L Gemmill
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Carla Osiowy
- Viral Hepatitis and Bloodborne Pathogens, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Guido van Marle
- Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, University of Calgary, Alberta, Canada
| | - Carla S Coffin
- Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, University of Calgary, Alberta, Canada; Department of Medicine, Cumming School of Medicine, Calgary, Alberta, Canada.
| | - Trushar R Patel
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada; Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, University of Calgary, Alberta, Canada; DiscoveryLab, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada.
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Patel A, Treffers EE, Meier M, Patel TR, Stetefeld J, Snijder EJ, Mark BL. Molecular characterization of the RNA-protein complex directing -2/-1 programmed ribosomal frameshifting during arterivirus replicase expression. J Biol Chem 2020; 295:17904-17921. [PMID: 33127640 PMCID: PMC7939443 DOI: 10.1074/jbc.ra120.016105] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 10/22/2020] [Indexed: 12/12/2022] Open
Abstract
Programmed ribosomal frameshifting (PRF) is a mechanism used by arteriviruses like porcine reproductive and respiratory syndrome virus (PRRSV) to generate multiple proteins from overlapping reading frames within its RNA genome. PRRSV employs -1 PRF directed by RNA secondary and tertiary structures within its viral genome (canonical PRF), as well as a noncanonical -1 and -2 PRF that are stimulated by the interactions of PRRSV nonstructural protein 1β (nsp1β) and host protein poly(C)-binding protein (PCBP) 1 or 2 with the viral genome. Together, nsp1β and one of the PCBPs act as transactivators that bind a C-rich motif near the shift site to stimulate -1 and -2 PRF, thereby enabling the ribosome to generate two frameshift products that are implicated in viral immune evasion. How nsp1β and PCBP associate with the viral RNA genome remains unclear. Here, we describe the purification of the nsp1β:PCBP2:viral RNA complex on a scale sufficient for structural analysis using small-angle X-ray scattering and stochiometric analysis by analytical ultracentrifugation. The proteins associate with the RNA C-rich motif as a 1:1:1 complex. The monomeric form of nsp1β within the complex differs from previously reported homodimer identified by X-ray crystallography. Functional analysis of the complex via mutational analysis combined with RNA-binding assays and cell-based frameshifting reporter assays reveal a number of key residues within nsp1β and PCBP2 that are involved in complex formation and function. Our results suggest that nsp1β and PCBP2 both interact directly with viral RNA during formation of the complex to coordinate this unusual PRF mechanism.
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Affiliation(s)
- Ankoor Patel
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Emmely E Treffers
- Molecular Virology Laboratory, Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Markus Meier
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Trushar R Patel
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Jörg Stetefeld
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Eric J Snijder
- Molecular Virology Laboratory, Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Brian L Mark
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada.
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Nelson CR, Mrozowich T, Park SM, D’souza S, Henrickson A, Vigar JRJ, Wieden HJ, Owens RJ, Demeler B, Patel TR. Human DDX17 Unwinds Rift Valley Fever Virus Non-Coding RNAs. Int J Mol Sci 2020; 22:E54. [PMID: 33374561 PMCID: PMC7793125 DOI: 10.3390/ijms22010054] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 12/15/2020] [Accepted: 12/21/2020] [Indexed: 01/20/2023] Open
Abstract
Rift Valley fever virus (RVFV) is a mosquito-transmitted virus from the Bunyaviridae family that causes high rates of mortality and morbidity in humans and ruminant animals. Previous studies indicated that DEAD-box helicase 17 (DDX17) restricts RVFV replication by recognizing two primary non-coding RNAs in the S-segment of the genome: the intergenic region (IGR) and 5' non-coding region (NCR). However, we lack molecular insights into the direct binding of DDX17 with RVFV non-coding RNAs and information on the unwinding of both non-coding RNAs by DDX17. Therefore, we performed an extensive biophysical analysis of the DDX17 helicase domain (DDX17135-555) and RVFV non-coding RNAs, IGR and 5' NCR. The homogeneity studies using analytical ultracentrifugation indicated that DDX17135-555, IGR, and 5' NCR are pure. Next, we performed small-angle X-ray scattering (SAXS) experiments, which suggested that DDX17 and both RNAs are homogenous as well. SAXS analysis also demonstrated that DDX17 is globular to an extent, whereas the RNAs adopt an extended conformation in solution. Subsequently, microscale thermophoresis (MST) experiments were performed to investigate the direct binding of DDX17 to the non-coding RNAs. The MST experiments demonstrated that DDX17 binds with the IGR and 5' NCR with a dissociation constant of 5.77 ± 0.15 µM and 9.85 ± 0.11 µM, respectively. As DDX17135-555 is an RNA helicase, we next determined if it could unwind IGR and NCR. We developed a helicase assay using MST and fluorescently-labeled oligos, which suggested DDX17135-555 can unwind both RNAs. Overall, our study provides direct evidence of DDX17135-555 interacting with and unwinding RVFV non-coding regions.
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Affiliation(s)
- Corey R. Nelson
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada; (C.R.N.); (T.M.); (S.M.P.); (A.H.); (J.R.J.V.); (H.-J.W.); (B.D.)
| | - Tyler Mrozowich
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada; (C.R.N.); (T.M.); (S.M.P.); (A.H.); (J.R.J.V.); (H.-J.W.); (B.D.)
| | - Sean M. Park
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada; (C.R.N.); (T.M.); (S.M.P.); (A.H.); (J.R.J.V.); (H.-J.W.); (B.D.)
| | - Simmone D’souza
- Department of Microbiology, Immunology and Infectious Disease, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 1N4, Canada;
| | - Amy Henrickson
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada; (C.R.N.); (T.M.); (S.M.P.); (A.H.); (J.R.J.V.); (H.-J.W.); (B.D.)
| | - Justin R. J. Vigar
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada; (C.R.N.); (T.M.); (S.M.P.); (A.H.); (J.R.J.V.); (H.-J.W.); (B.D.)
| | - Hans-Joachim Wieden
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada; (C.R.N.); (T.M.); (S.M.P.); (A.H.); (J.R.J.V.); (H.-J.W.); (B.D.)
| | - Raymond J. Owens
- Research Complex at Harwell, R92 Rutherford Appleton Laboratories, Harwell, Oxford OX1 0QX, UK;
| | - Borries Demeler
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada; (C.R.N.); (T.M.); (S.M.P.); (A.H.); (J.R.J.V.); (H.-J.W.); (B.D.)
- Department of Chemistry and Biochemistry, University of Montana, Missoula, MT 59812, USA
- NorthWest Biophysics Consortium, University of Lethbridge, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada
| | - Trushar R. Patel
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada; (C.R.N.); (T.M.); (S.M.P.); (A.H.); (J.R.J.V.); (H.-J.W.); (B.D.)
- Department of Microbiology, Immunology and Infectious Disease, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 1N4, Canada;
- Li Ka Shing Institute of Virology and Discovery Lab, University of Alberta, Edmonton, AB T6G 2E1, Canada
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Lenarčič Živković M, Rozman J, Plavec J. Structure of a DNA G-Quadruplex Related to Osteoporosis with a G-A Bulge Forming a Pseudo-loop. Molecules 2020; 25:E4867. [PMID: 33096904 PMCID: PMC7588008 DOI: 10.3390/molecules25204867] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 10/19/2020] [Accepted: 10/19/2020] [Indexed: 11/30/2022] Open
Abstract
Bone remodeling is a fine-tuned process principally regulated by a cascade triggered by interaction of receptor activator of NF-κB (RANK) and RANK ligand (RANKL). Excessive activity of the RANKL gene leads to increased bone resorption and can influence the incidence of osteoporosis. Although much has been learned about the intracellular signals activated by RANKL/RANK complex, significantly less is known about the molecular mechanisms of regulation of RANKL expression. Here, we report on the structure of an unprecedented DNA G-quadruplex, well-known secondary structure-mediated gene expression regulator, formed by a G-rich sequence found in the regulatory region of a RANKL gene. Solution-state NMR structural study reveals the formation of a three-layered parallel-type G-quadruplex characterized by an unique features, including a G-A bulge. Although a guanine within a G-tract occupies syn glycosidic conformation, bulge-forming residues arrange in a pseudo-loop conformation to facilitate partial 5/6-ring stacking, typical of G-quadruplex structures with parallel G-tracts orientation. Such distinctive structural features protruding from the core of the structure can represent a novel platform for design of highly specific ligands with anti-osteoporotic function. Additionally, our study suggests that the expression of RANKL gene may be regulated by putative folding of its G-rich region into non-B-DNA structure(s).
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Affiliation(s)
- Martina Lenarčič Živković
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia;
- Central European Institute of Technology, Masaryk University, Kamenice 753/5, 62500 Brno, Czech Republic
| | - Jan Rozman
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia;
| | - Janez Plavec
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia;
- EN-FIST Centre of Excellence, Trg OF 13, 1000 Ljubljana, Slovenia
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, 1000 Ljubljana, Slovenia
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Lu XJ. DSSR-enabled innovative schematics of 3D nucleic acid structures with PyMOL. Nucleic Acids Res 2020; 48:e74. [PMID: 32442277 PMCID: PMC7367123 DOI: 10.1093/nar/gkaa426] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 04/26/2020] [Accepted: 05/07/2020] [Indexed: 12/11/2022] Open
Abstract
Sophisticated analysis and simplified visualization are crucial for understanding complicated structures of biomacromolecules. DSSR (Dissecting the Spatial Structure of RNA) is an integrated computational tool that has streamlined the analysis and annotation of 3D nucleic acid structures. The program creates schematic block representations in diverse styles that can be seamlessly integrated into PyMOL and complement its other popular visualization options. In addition to portraying individual base blocks, DSSR can draw Watson-Crick pairs as long blocks and highlight the minor-groove edges. Notably, DSSR can dramatically simplify the depiction of G-quadruplexes by automatically detecting G-tetrads and treating them as large square blocks. The DSSR-enabled innovative schematics with PyMOL are aesthetically pleasing and highly informative: the base identity, pairing geometry, stacking interactions, double-helical stems, and G-quadruplexes are immediately obvious. These features can be accessed via four interfaces: the command-line interface, the DSSR plugin for PyMOL, the web application, and the web application programming interface. The supplemental PDF serves as a practical guide, with complete and reproducible examples. Thus, even beginners or occasional users can get started quickly, especially via the web application at http://skmatic.x3dna.org.
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Affiliation(s)
- Xiang-Jun Lu
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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20
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Monsen RC, DeLeeuw L, Dean WL, Gray RD, Sabo T, Chakravarthy S, Chaires JB, Trent JO. The hTERT core promoter forms three parallel G-quadruplexes. Nucleic Acids Res 2020; 48:5720-5734. [PMID: 32083666 PMCID: PMC7261196 DOI: 10.1093/nar/gkaa107] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/06/2020] [Accepted: 02/17/2020] [Indexed: 12/13/2022] Open
Abstract
The structure of the 68 nt sequence with G-quadruplex forming potential within the hTERT promoter is disputed. One model features a structure with three stacked parallel G-quadruplex units, while another features an unusual duplex hairpin structure adjoined to two stacked parallel and antiparallel quadruplexes. We report here the results of an integrated structural biology study designed to distinguish between these possibilities. As part of our study, we designed a sequence with an optimized hairpin structure and show that its biophysical and biochemical properties are inconsistent with the structure formed by the hTERT wild-type sequence. By using circular dichroism, thermal denaturation, nuclear magnetic resonance spectroscopy, analytical ultracentrifugation, small-angle X-ray scattering, molecular dynamics simulations and a DNase I cleavage assay we found that the wild type hTERT core promoter folds into a stacked, three-parallel G-quadruplex structure. The hairpin structure is inconsistent with all of our experimental data obtained with the wild-type sequence. All-atom models for both structures were constructed using molecular dynamics simulations. These models accurately predicted the experimental hydrodynamic properties measured for each structure. We found with certainty that the wild-type hTERT promoter sequence does not form a hairpin structure in solution, but rather folds into a compact stacked three-G-quadruplex conformation.
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Affiliation(s)
- Robert C Monsen
- Department of Biochemistry & Molecular Genetics, University of Louisville, Louisville, KY 40202, USA
| | - Lynn DeLeeuw
- James Graham Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA
| | - William L Dean
- James Graham Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA
| | - Robert D Gray
- James Graham Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA
| | - T Michael Sabo
- Department of Biochemistry & Molecular Genetics, University of Louisville, Louisville, KY 40202, USA
- James Graham Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA
- Department of Medicine, University of Louisville, Louisville, KY 40202, USA
| | - Srinivas Chakravarthy
- The Biophysics Collaborative Access Team (BioCAT), Department of Biological Chemical and Physical Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Jonathan B Chaires
- Department of Biochemistry & Molecular Genetics, University of Louisville, Louisville, KY 40202, USA
- James Graham Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA
- Department of Medicine, University of Louisville, Louisville, KY 40202, USA
| | - John O Trent
- Department of Biochemistry & Molecular Genetics, University of Louisville, Louisville, KY 40202, USA
- James Graham Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA
- Department of Medicine, University of Louisville, Louisville, KY 40202, USA
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21
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Vannutelli A, Belhamiti S, Garant JM, Ouangraoua A, Perreault JP. Where are G-quadruplexes located in the human transcriptome? NAR Genom Bioinform 2020; 2:lqaa035. [PMID: 33575590 PMCID: PMC7671396 DOI: 10.1093/nargab/lqaa035] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 04/28/2020] [Accepted: 05/05/2020] [Indexed: 12/23/2022] Open
Abstract
It has been demonstrated that RNA G-quadruplexes (G4) are structural motifs present in transcriptomes and play important regulatory roles in several post-transcriptional mechanisms. However, the full picture of RNA G4 locations and the extent of their implication remain elusive. Solely computational prediction analysis of the whole transcriptome may reveal all potential G4, since experimental identifications are always limited to specific conditions or specific cell lines. The present study reports the first in-depth computational prediction of potential G4 region across the complete human transcriptome. Although using a relatively stringent approach based on three prediction scores that accounts for the composition of G4 sequences, the composition of their neighboring sequences, and the various forms of G4, over 1.1 million of potential G4 (pG4) were predicted. The abundance of G4 was computationally confirmed in both 5' and 3'UTR as well as splicing junction of mRNA, appreciate for the first time in the long ncRNA, while almost absent of most of the small ncRNA families. The present results constitute an important step toward a full understanding of the roles of G4 in post-transcriptional mechanisms.
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Affiliation(s)
- Anaïs Vannutelli
- Department of Computer Science, Faculté des sciences, Université de Sherbrooke, QC J1K 2R1, Canada
- Department of Biochemistry and Functional Genomics, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, QC J1E 4K8, Canada
| | - Sarah Belhamiti
- Department of Computer Science, Faculté des sciences, Université de Sherbrooke, QC J1K 2R1, Canada
- Department of Biochemistry and Functional Genomics, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, QC J1E 4K8, Canada
| | - Jean-Michel Garant
- Department of Biochemistry and Functional Genomics, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, QC J1E 4K8, Canada
| | - Aida Ouangraoua
- Department of Computer Science, Faculté des sciences, Université de Sherbrooke, QC J1K 2R1, Canada
| | - Jean-Pierre Perreault
- Department of Biochemistry and Functional Genomics, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, QC J1E 4K8, Canada
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22
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Maity A, Winnerdy FR, Chang WD, Chen G, Phan AT. Intra-locked G-quadruplex structures formed by irregular DNA G-rich motifs. Nucleic Acids Res 2020; 48:3315-3327. [PMID: 32100003 PMCID: PMC7102960 DOI: 10.1093/nar/gkaa008] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 12/30/2019] [Accepted: 02/24/2020] [Indexed: 12/14/2022] Open
Abstract
G-rich DNA sequences with tracts of three or more continuous guanines (G≥3) are known to have high propensity to adopt stable G-quadruplex (G4) structures. Bioinformatic analyses suggest high prevalence of G-rich sequences with short G-tracts (G≤2) in the human genome. However, due to limited structural studies, the folding principles of such sequences remain largely unexplored and hence poorly understood. Here, we present the solution NMR structure of a sequence named AT26 consisting of irregularly spaced G2 tracts and two isolated single guanines. The structure is a four-layered G4 featuring two bi-layered blocks, locked between themselves in an unprecedented fashion making it a stable scaffold. In addition to edgewise and propeller-type loops, AT26 also harbors two V-shaped loops: a 2-nt V-shaped loop spanning two G-tetrad layers and a 0-nt V-shaped loop spanning three G-tetrad layers, which are named as VS- and VR-loop respectively, based on their distinct structural features. The intra-lock motif can be a basis for extending the G-tetrad core and a very stable intra-locked G4 can be formed by a sequence with G-tracts of various lengths including several G2 tracts. Findings from this study will aid in understanding the folding of G4 topologies from sequences containing irregularly spaced multiple short G-tracts.
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Affiliation(s)
- Arijit Maity
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Fernaldo Richtia Winnerdy
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Weili Denyse Chang
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Gang Chen
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Anh Tuân Phan
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.,NTU Institute of Structural Biology, Nanyang Technological University, Singapore 636921, Singapore
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23
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Koul A, Gemmill D, Lubna N, Meier M, Krahn N, Booy EP, Stetefeld J, Patel TR, McKenna SA. Structural and Hydrodynamic Characterization of Dimeric Human Oligoadenylate Synthetase 2. Biophys J 2020; 118:2726-2740. [PMID: 32413313 PMCID: PMC7264852 DOI: 10.1016/j.bpj.2020.04.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 04/15/2020] [Accepted: 04/24/2020] [Indexed: 12/20/2022] Open
Abstract
Oligoadenylate synthetases (OASs) are a family of interferon-inducible enzymes that require double-stranded RNA (dsRNA) as a cofactor. Upon binding dsRNA, OAS undergoes a conformational change and is activated to polymerize ATP into 2'-5'-oligoadenylate chains. The OAS family consists of several isozymes, with unique domain organizations to potentially interact with dsRNA of variable length, providing diversity in viral RNA recognition. In addition, oligomerization of OAS isozymes, potentially OAS1 and OAS2, is hypothesized to be important for 2'-5'-oligoadenylate chain building. In this study, we present the solution conformation of dimeric human OAS2 using an integrated approach involving small-angle x-ray scattering, analytical ultracentrifugation, and dynamic light scattering techniques. We also demonstrate OAS2 dimerization using immunoprecipitation approaches in human cells. Whereas mutation of a key active-site aspartic acid residue prevents OAS2 activity, a C-terminal mutation previously hypothesized to disrupt OAS self-association had only a minor effect on OAS2 activity. Finally, we also present the solution structure of OAS1 monomer and dimer, comparing their hydrodynamic properties with OAS2. In summary, our work presents the first, to our knowledge, dimeric structural models of OAS2 that enhance our understanding of the oligomerization and catalytic function of OAS enzymes.
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Affiliation(s)
- Amit Koul
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Darren Gemmill
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Nikhat Lubna
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Markus Meier
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Natalie Krahn
- Department of Molecular Biology and Biochemistry, Yale University, New Haven, Connecticut
| | - Evan P Booy
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Jörg Stetefeld
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Trushar R Patel
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada; Department of Microbiology, Immunology and Infectious Disease, Cumming School of Medicine, University of Calgary, Northwest Calgary, Alberta, Canada; Li Ka Shing Institute of Virology and Discovery Lab, University of Alberta, Edmonton, Alberta, Canada.
| | - Sean A McKenna
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada; Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Manitoba, Canada.
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24
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Mrozowich T, Henrickson A, Demeler B, Patel TR. Nanoscale Structure Determination of Murray Valley Encephalitis and Powassan Virus Non-Coding RNAs. Viruses 2020; 12:E190. [PMID: 32046304 PMCID: PMC7077200 DOI: 10.3390/v12020190] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 02/05/2020] [Accepted: 02/06/2020] [Indexed: 01/02/2023] Open
Abstract
Viral infections are responsible for numerous deaths worldwide. Flaviviruses, which contain RNA as their genetic material, are one of the most pathogenic families of viruses. There is an increasing amount of evidence suggesting that their 5' and 3' non-coding terminal regions are critical for their survival. Information on their structural features is essential to gain detailed insights into their functions and interactions with host proteins. In this study, the 5' and 3' terminal regions of Murray Valley encephalitis virus and Powassan virus were examined using biophysical and computational modeling methods. First, we used size exclusion chromatography and analytical ultracentrifuge methods to investigate the purity of in-vitro transcribed RNAs. Next, we employed small-angle X-ray scattering techniques to study solution conformation and low-resolution structures of these RNAs, which suggest that the 3' terminal regions are highly extended as compared to the 5' terminal regions for both viruses. Using computational modeling tools, we reconstructed 3-dimensional structures of each RNA fragment and compared them with derived small-angle X-ray scattering low-resolution structures. This approach allowed us to reinforce that the 5' terminal regions adopt more dynamic structures compared to the mainly double-stranded structures of the 3' terminal regions.
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Affiliation(s)
- Tyler Mrozowich
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada; (T.M.); (A.H.); (B.D.)
| | - Amy Henrickson
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada; (T.M.); (A.H.); (B.D.)
| | - Borries Demeler
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada; (T.M.); (A.H.); (B.D.)
- Department of Chemistry And Biochemistry, University of Montana, Missoula, MT 59812, USA
- NorthWest Biophysics Consortium, University of Lethbridge, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada
| | - Trushar R Patel
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada; (T.M.); (A.H.); (B.D.)
- NorthWest Biophysics Consortium, University of Lethbridge, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada
- Department of Microbiology, Immunology and Infectious Disease, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 1N4, Canada
- Li Ka Shing Institute of Virology and Discovery Lab, University of Alberta, Edmonton, AB T6G 2E1, Canada
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25
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Kim DN, Thiel BC, Mrozowich T, Hennelly SP, Hofacker IL, Patel TR, Sanbonmatsu KY. Zinc-finger protein CNBP alters the 3-D structure of lncRNA Braveheart in solution. Nat Commun 2020; 11:148. [PMID: 31919376 PMCID: PMC6952434 DOI: 10.1038/s41467-019-13942-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Accepted: 12/09/2019] [Indexed: 02/08/2023] Open
Abstract
Long non-coding RNAs (lncRNAs) constitute a significant fraction of the transcriptome, playing important roles in development and disease. However, our understanding of structure-function relationships for this emerging class of RNAs has been limited to secondary structures. Here, we report the 3-D atomistic structural study of epigenetic lncRNA, Braveheart (Bvht), and its complex with CNBP (Cellular Nucleic acid Binding Protein). Using small angle X-ray scattering (SAXS), we elucidate the ensemble of Bvht RNA conformations in solution, revealing that Bvht lncRNA has a well-defined, albeit flexible 3-D structure that is remodeled upon CNBP binding. Our study suggests that CNBP binding requires multiple domains of Bvht and the RHT/AGIL RNA motif. We show that RHT/AGIL, previously shown to interact with CNBP, contains a highly flexible loop surrounded by more ordered helices. As one of the largest RNA-only 3-D studies, the work lays the foundation for future structural studies of lncRNA-protein complexes.
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Affiliation(s)
- Doo Nam Kim
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Bernhard C Thiel
- Department of Theoretical Chemistry, University of Vienna, Vienna, Austria
| | - Tyler Mrozowich
- Alberta RNA Research & Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Scott P Hennelly
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
- New Mexico Consortium, Los Alamos, New Mexico, USA
| | - Ivo L Hofacker
- Department of Theoretical Chemistry, University of Vienna, Vienna, Austria
- Bioinformatics and Computational Biology, Faculty of Computer Science, University of Vienna, Vienna, Austria
| | - Trushar R Patel
- Alberta RNA Research & Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada.
- Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
- Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alberta, Canada.
| | - Karissa Y Sanbonmatsu
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, New Mexico, USA.
- New Mexico Consortium, Los Alamos, New Mexico, USA.
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26
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Moccia F, Riccardi C, Musumeci D, Leone S, Oliva R, Petraccone L, Montesarchio D. Insights into the G-rich VEGF-binding aptamer V7t1: when two G-quadruplexes are better than one! Nucleic Acids Res 2019; 47:8318-8331. [PMID: 31276595 PMCID: PMC6735921 DOI: 10.1093/nar/gkz589] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 06/24/2019] [Accepted: 06/25/2019] [Indexed: 12/20/2022] Open
Abstract
The G-quadruplex-forming VEGF-binding aptamer V7t1 was previously found to be highly polymorphic in a K+-containing solution and, to restrict its conformational preferences to a unique, well-defined form, modified nucleotides (LNA and/or UNA) were inserted in its sequence. We here report an in-depth biophysical characterization of V7t1 in a Na+-rich medium, mimicking the extracellular environment in which VEGF targeting should occur, carried out combining several techniques to analyse the conformational behaviour of the aptamer and its binding to the protein. Our results demonstrate that, in the presence of high Na+ concentrations, V7t1 behaves in a very different way if subjected or not to annealing procedures, as evidenced by native gel electrophoresis, size exclusion chromatography and dynamic light scattering analysis. Indeed, not-annealed V7t1 forms both monomeric and dimeric G-quadruplexes, while the annealed oligonucleotide is a monomeric species. Remarkably, only the dimeric aptamer efficiently binds VEGF, showing higher affinity for the protein compared to the monomeric species. These findings provide new precious information for the development of improved V7t1 analogues, allowing more efficient binding to the cancer-related protein and the design of effective biosensors or theranostic devices based on VEGF targeting.
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Affiliation(s)
- Federica Moccia
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 21, I-80126 Napoli, Italy
| | - Claudia Riccardi
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 21, I-80126 Napoli, Italy
| | - Domenica Musumeci
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 21, I-80126 Napoli, Italy.,Institute of Biostructures and Bioimages, CNR, Via Mezzocannone 16, I-80134 Napoli, Italy
| | - Serena Leone
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 21, I-80126 Napoli, Italy
| | - Rosario Oliva
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 21, I-80126 Napoli, Italy
| | - Luigi Petraccone
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 21, I-80126 Napoli, Italy
| | - Daniela Montesarchio
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 21, I-80126 Napoli, Italy.,Institute for Endocrinology and Oncology 'Gaetano Salvatore', CNR, Via Pansini 5, 80131 Napoli, Italy
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27
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Mrozowich T, Winzor DJ, Scott DJ, Patel TR. Experimental determination of second virial coefficients by small-angle X-ray scattering: a problem revisited. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2019; 48:781-787. [PMID: 31667558 DOI: 10.1007/s00249-019-01404-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 10/01/2019] [Accepted: 10/10/2019] [Indexed: 11/24/2022]
Abstract
This investigation examines the validity of employing single-solute theory to interpret SAXS measurements on buffered protein solutions-the current practice despite the necessity to regard the buffer components as additional non-scattering solutes rather than as part of the solvent. The present study of bovine serum albumin in phosphate-buffered saline supplemented with 20-100 g/L sucrose as small cosolute has certainly verified the prediction that the experimentally obtained second virial coefficient should contain protein-cosolute contributions. Nevertheless, the second virial coefficient determined for protein solutions supplemented with high cosolute concentrations on the basis of single-solute theory remains a valid means for identifying conditions conducive to protein crystallization, because the return of a slightly negative second virial coefficient based on single-solute theory [Formula: see text] still establishes the existence of slightly associative interactions between protein molecules, irrespective of the molecular source-protein self-interactions and/or protein-cosolute contributions.
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Affiliation(s)
- Tyler Mrozowich
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB, T1K 3M4, Canada
| | - Donald J Winzor
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, 4072, Australia
| | - David J Scott
- National Centre for Macromolecular Hydrodynamics, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Nottingham, LE12 5RD, UK. .,ISIS Spallation Neutron and Muon Source, Rutherton Appleton Research Complex at Harwell, Harwell, OX11 OFA, UK.
| | - Trushar R Patel
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB, T1K 3M4, Canada. .,Department of Microbiology, Immunology and Infectious Disease, Cumming School of Medicine, University of Calgary, Calgary, T2N 1N4, AB, Canada. .,Li Ka Shing Institute of Virology and Discovery Lab, University of Alberta, Edmonton, AB, T6G 2E1, Canada.
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28
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Majdi Yazdi M, Saran S, Mrozowich T, Lehnert C, Patel TR, Sanders DAR, Palmer DRJ. Asparagine-84, a regulatory allosteric site residue, helps maintain the quaternary structure of Campylobacter jejuni dihydrodipicolinate synthase. J Struct Biol 2019; 209:107409. [PMID: 31678256 DOI: 10.1016/j.jsb.2019.107409] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 10/18/2019] [Accepted: 10/28/2019] [Indexed: 02/05/2023]
Abstract
Dihydrodipicolinate synthase (DHDPS) from Campylobacter jejuni is a natively homotetrameric enzyme that catalyzes the first unique reaction of (S)-lysine biosynthesis and is feedback-regulated by lysine through binding to an allosteric site. High-resolution structures of the DHDPS-lysine complex have revealed significant insights into the binding events. One key asparagine residue, N84, makes hydrogen bonds with both the carboxyl and the α-amino group of the bound lysine. We generated two mutants, N84A and N84D, to study the effects of these changes on the allosteric site properties. However, under normal assay conditions, N84A displayed notably lower catalytic activity, and N84D showed no activity. Here we show that these mutations disrupt the quaternary structure of DHDPS in a concentration-dependent fashion, as demonstrated by size-exclusion chromatography, multi-angle light scattering, dynamic light scattering, small-angle X-ray scattering (SAXS) and high-resolution protein crystallography.
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Affiliation(s)
- Mohadeseh Majdi Yazdi
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada
| | - Sagar Saran
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada
| | - Tyler Mrozowich
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta T1K 3M4, Canada
| | - Cheyanne Lehnert
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada
| | - Trushar R Patel
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta T1K 3M4, Canada; Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, University of Calgary, 2500 University Dr. NW, Calgary, Alberta T2N 1N4, Canada; Li Ka Shing Institute of Virology and DiscoveryLab, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
| | - David A R Sanders
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada.
| | - David R J Palmer
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada.
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29
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Why do G-quadruplexes dimerize through the 5'-ends? Driving forces for G4 DNA dimerization examined in atomic detail. PLoS Comput Biol 2019; 15:e1007383. [PMID: 31539370 PMCID: PMC6774569 DOI: 10.1371/journal.pcbi.1007383] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 10/02/2019] [Accepted: 09/09/2019] [Indexed: 12/25/2022] Open
Abstract
G-quadruplexes (G4) are secondary structures formed by guanine-rich nucleic acid sequences and shown to exist in living cells where they participate in regulation of gene expression and chromosome maintenance. G-quadruplexes with solvent-exposed guanine tetrads show the tendency to associate together through cofacial stacking, which may be important for packaging of G4-forming sequences and allows for the design of higher-order G4 DNA structures. To understand the molecular driving forces for G4 association, here, we study the binding interaction between two parallel-stranded G-quadruplexes using all-atom molecular dynamics simulations. The predicted dimerization free energies show that direct binding through the 5’-G-tetrads is the most preferred of all possible end-to-end stacking orientations, consistently with all available experimental data. Decomposition of dimerization enthalpies in combination with simulations at varying ionic strength further indicate that the observed orientational preferences arise from a fine balance between the electrostatic repulsion of the sugar-phosphate backbones and favorable counterion binding at the dimeric interface. We also demonstrate how these molecular-scale findings can be used to devise means of controlling G4 dimerization equilibrium, e.g., by altering salt concentration and using G4-targeted ligands. Native DNA usually folds to form the canonical double helix, however, under certain conditions, it can also fold into other secondary structures. Some of the most interesting ones are G-quadruplexes (G4)—compact DNA structures in which guanines assemble into multilayered tetrads, and whose formation has been reported at the ends of linear chromosomes (telomeres) and at different regulatory regions of the genome. Although structural and basic energetic properties, as well as some biological functions of G-quadruplexes are quite well understood, not much is known about their propensity to form agregated structures. A very high density of G-quadruplexes at telomeres along with their large exposed planar surfaces indeed favor G4 aggregation through end-to-end stacking, which might be important for the protection of telomeres and DNA packaging. In this research, using computer simulations, we provide insight into molecular origins of stability of the higher-order G-quadruplexes and explain in structural and energetic terms a strong preference for one particular end-to-end stacking orientation. Based on the recognized aggregation driving forces, we also suggest methods for controling the aggregation preferences openining up new opportunities for designing oligomeric G-quadruplexes.
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30
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Lightfoot HL, Hagen T, Tatum NJ, Hall J. The diverse structural landscape of quadruplexes. FEBS Lett 2019; 593:2083-2102. [PMID: 31325371 DOI: 10.1002/1873-3468.13547] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 07/09/2019] [Accepted: 07/15/2019] [Indexed: 12/15/2022]
Abstract
G-quadruplexes are secondary structures formed in G-rich sequences in DNA and RNA. Considerable research over the past three decades has led to in-depth insight into these unusual structures in DNA. Since the more recent exploration into RNA G-quadruplexes, such structures have demonstrated their in cellulo existence, function and roles in pathology. In comparison to Watson-Crick-based secondary structures, most G-quadruplexes display highly redundant structural characteristics. However, numerous reports of G-quadruplex motifs/structures with unique features (e.g. bulges, long loops, vacancy) have recently surfaced, expanding the repertoire of G-quadruplex scaffolds. This review addresses G-quadruplex formation and structure, including recent reports of non-canonical G-quadruplex structures. Improved methods of detection will likely further expand this collection of novel structures and ultimately change the face of quadruplex-RNA targeting as a therapeutic strategy.
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Affiliation(s)
- Helen L Lightfoot
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH Zurich, Switzerland
| | - Timo Hagen
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH Zurich, Switzerland
| | - Natalie J Tatum
- Newcastle Cancer Centre, Northern Institute for Cancer Research, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Jonathan Hall
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH Zurich, Switzerland
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31
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Ruggiero E, Tassinari M, Perrone R, Nadai M, Richter SN. Stable and Conserved G-Quadruplexes in the Long Terminal Repeat Promoter of Retroviruses. ACS Infect Dis 2019; 5:1150-1159. [PMID: 31081611 PMCID: PMC6630527 DOI: 10.1021/acsinfecdis.9b00011] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
![]()
Retroviruses
infect almost all vertebrates, from humans to domestic and farm animals,
from primates to wild animals, where they cause severe diseases, including
immunodeficiencies, neurological disorders, and cancer. Nonhuman retroviruses
have also been recently associated with human diseases. To date, no
effective treatments are available; therefore, finding retrovirus-specific
therapeutic targets is becoming an impelling issue. G-Quadruplexes
are four-stranded nucleic acid structures that form in guanine-rich
regions. Highly conserved G-quadruplexes located in the long-terminal-repeat
(LTR) promoter of HIV-1 were shown to modulate the virus transcription
machinery; moreover, the astonishingly high degree of conservation
of G-quadruplex sequences in all primate lentiviruses corroborates
the idea that these noncanonical nucleic acid structures are crucial
elements in the lentiviral biology and thus have been selected for
during evolution. In this work, we aimed at investigating the presence
and conservation of G-quadruplexes in the Retroviridae family. Genomewide
bioinformatics analysis showed that, despite their documented high
genetic variability, most retroviruses contain highly conserved putative
G-quadruplex-forming sequences in their promoter regions. Biophysical
and biomolecular assays proved that these sequences actually fold
into G-quadruplexes in physiological concentrations of relevant cations
and that they are further stabilized by ligands. These results validate
the relevance of G-quadruplexes in retroviruses and endorse the employment
of G-quadruplex ligands as innovative antiretroviral drugs. This study
indicates new possible pathways in the management of retroviral infections
in humans and animal species. Moreover, it may shed light on the mechanism
and functions of retrovirus genomes and derived transposable elements
in the human genome.
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Affiliation(s)
- Emanuela Ruggiero
- Department of Molecular Medicine, University of Padua, via Aristide Gabelli 63, 35121 Padua, Italy
| | - Martina Tassinari
- Department of Molecular Medicine, University of Padua, via Aristide Gabelli 63, 35121 Padua, Italy
| | - Rosalba Perrone
- Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, California 94945, United States
| | - Matteo Nadai
- Department of Molecular Medicine, University of Padua, via Aristide Gabelli 63, 35121 Padua, Italy
| | - Sara N. Richter
- Department of Molecular Medicine, University of Padua, via Aristide Gabelli 63, 35121 Padua, Italy
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Li S, Olson WK, Lu XJ. Web 3DNA 2.0 for the analysis, visualization, and modeling of 3D nucleic acid structures. Nucleic Acids Res 2019; 47:W26-W34. [PMID: 31114927 PMCID: PMC6602438 DOI: 10.1093/nar/gkz394] [Citation(s) in RCA: 144] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 04/23/2019] [Accepted: 05/01/2019] [Indexed: 12/17/2022] Open
Abstract
Web 3DNA (w3DNA) 2.0 is a significantly enhanced version of the widely used w3DNA server for the analysis, visualization, and modeling of 3D nucleic-acid-containing structures. Since its initial release in 2009, the w3DNA server has continuously served the community by making commonly-used features of the 3DNA suite of command-line programs readily accessible. However, due to the lack of updates, w3DNA has clearly shown its age in terms of modern web technologies and it has long lagged behind further developments of 3DNA per se. The w3DNA 2.0 server presented here overcomes all known shortcomings of w3DNA while maintaining its battle-tested characteristics. Technically, w3DNA 2.0 implements a simple and intuitive interface (with sensible defaults) for increased usability, and it complies with HTML5 web standards for broad accessibility. Featurewise, w3DNA 2.0 employs the most recent version of 3DNA, enhanced with many new functionalities, including: the automatic handling of modified nucleotides; a set of 'simple' base-pair and step parameters for qualitative characterization of non-Watson-Crick double-helical structures; new structural parameters that integrate the rigid base plane and the backbone phosphate group, the two nucleic acid components most reliably determined with X-ray crystallography; in silico base mutations that preserve the backbone geometry; and a notably improved module for building models of single-stranded RNA, double-helical DNA, Pauling triplex, G-quadruplex, or DNA structures 'decorated' with proteins. The w3DNA 2.0 server is freely available, without registration, at http://web.x3dna.org.
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Affiliation(s)
- Shuxiang Li
- Department of Chemistry & Chemical Biology and Center for Quantitative Biology, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA
| | - Wilma K Olson
- Department of Chemistry & Chemical Biology and Center for Quantitative Biology, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA
| | - Xiang-Jun Lu
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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Krahn N, Meier M, Reuten R, Koch M, Stetefeld J, Patel TR. Solution Structure of C. elegans UNC-6: A Nematode Paralogue of the Axon Guidance Protein Netrin-1. Biophys J 2019; 116:2121-2130. [PMID: 31103237 DOI: 10.1016/j.bpj.2019.04.033] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 04/09/2019] [Accepted: 04/29/2019] [Indexed: 12/14/2022] Open
Abstract
UNCoordinated-6 (UNC-6) was the first member of the netrin family to be discovered in Caenorhabditis elegans. With homology to human netrin-1, it is a key signaling molecule involved in directing axon migration in nematodes. Similar to netrin-1, UNC-6 interacts with multiple receptors (UNC-5 and UNC-40, specifically) to guide axon migration in development. As a result of the distinct evolutionary path of UNC-6 compared to vertebrate netrins, we decided to employ an integrated approach to study its solution behavior and compare it to the high-resolution structure we previously published on vertebrate netrins. Dynamic light scattering and analytical ultracentrifugation on UNC-6 (with and without its C-domain) solubilized in a low-ionic strength buffer suggested that UNC-6 forms high-order oligomers. An increase in the buffer ionic strength resulted in a more homogeneous preparation of UNC-6, that was used for subsequent solution x-ray scattering experiments. Our biophysical analysis of UNC-6 ΔC solubilized in a high-ionic strength buffer suggested that it maintains a similar head-to-stalk arrangement as netrins -1 and -4. This phenomenon is thought to play a role in the signaling behavior of UNC-6 and its ability to move throughout the extracellular matrix.
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Affiliation(s)
- Natalie Krahn
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut
| | - Markus Meier
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Raphael Reuten
- Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Manuel Koch
- Institute for Dental Research and Oral Musculoskeletal Biology, Medical Faculty, University of Cologne, Cologne, Germany; Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany
| | - Joerg Stetefeld
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada; Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Manitoba, Canada.
| | - Trushar R Patel
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada; Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; DiscoveryLab and Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alberta, Canada.
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Chan CY, Umar MI, Kwok CK. Spectroscopic analysis reveals the effect of a single nucleotide bulge on G-quadruplex structures. Chem Commun (Camb) 2019; 55:2616-2619. [PMID: 30724299 DOI: 10.1039/c8cc09929d] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Here we investigate and reveal the effect of bulge position and bulge identity on G-quadruplexes using label-free spectroscopic techniques. Notably, we report significant differences in the spectroscopic features of bulged DNA and RNA G-quadruplexes, and demonstrate that intrinsic fluorescence can be generally used to detect the formation of canonical and non-canonical G-quadruplexes.
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Affiliation(s)
- Chun-Yin Chan
- Department of Chemistry, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China.
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35
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D'Eall C, Pon RA, Rossotti MA, Krahn N, Spearman M, Callaghan D, van Faassen H, Hussack G, Stetefeld J, Butler M, Durocher Y, Zhang J, Henry KA, Tanha J. Modulating antibody-dependent cellular cytotoxicity of epidermal growth factor receptor-specific heavy-chain antibodies through hinge engineering. Immunol Cell Biol 2019; 97:526-537. [PMID: 30680791 DOI: 10.1111/imcb.12238] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 01/22/2019] [Accepted: 01/22/2019] [Indexed: 01/20/2023]
Abstract
Human IgG1 and IgG3 antibodies (Abs) can mediate Ab-dependent cellular cytotoxicity (ADCC), and engineering of the Ab Fc (point mutation; defucosylation) has been shown to affect ADCC by modulating affinity for FcRγIIIa. In the absence of a CH 1 domain, many camelid heavy-chain Abs (HCAbs) naturally bear very long and flexible hinge regions connecting their VH H and CH 2 domains. To better understand the influence of hinge length and structure on HCAb ADCC, we produced a series of hinge-engineered epidermal growth factor receptor (EGFR)-specific chimeric camelid VH H-human Fc Abs and characterized their affinities for recombinant EGFR and FcRγIIIa, their binding to EGFR-positive tumor cells, and their ability to elicit ADCC. In the case of one chimeric HCAb (EG2-hFc), we found that variants bearing longer hinges (IgG3 or camelid hinge regions) showed dramatically improved ADCC in comparison with a variant bearing the human IgG1 hinge, in similar fashion to a variant with reduced CH 2 fucosylation. Conversely, an EG2-hFc variant bearing a truncated human IgG1 upper hinge region failed to elicit ADCC. However, there was no consistent association between hinge length and ADCC for four similarly engineered chimeric HCAbs directed against distinct EGFR epitopes. These findings demonstrate that the ADCC of some HCAbs can be modulated simply by varying the length of the Ab hinge. Although this effect appears to be heavily epitope-dependent, this strategy may be useful to consider during the design of VH H-based therapeutic Abs for cancer.
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Affiliation(s)
- Calvin D'Eall
- Human Health Therapeutics Research Centre, National Research Council Canada, 100 Sussex Drive, Ottawa, ON, K1A 0R6, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Robert A Pon
- Human Health Therapeutics Research Centre, National Research Council Canada, 100 Sussex Drive, Ottawa, ON, K1A 0R6, Canada
| | - Martin A Rossotti
- Human Health Therapeutics Research Centre, National Research Council Canada, 100 Sussex Drive, Ottawa, ON, K1A 0R6, Canada
| | - Natalie Krahn
- Department of Chemistry, University of Manitoba, 144 Dysart Road, Winnipeg, MB, R3T 2N2, Canada
| | - Maureen Spearman
- Department of Microbiology, University of Manitoba, 144 Dysart Road, Winnipeg, MB, R3T 2N2, Canada
| | - Deborah Callaghan
- Human Health Therapeutics Research Centre, National Research Council Canada, 100 Sussex Drive, Ottawa, ON, K1A 0R6, Canada
| | - Henk van Faassen
- Human Health Therapeutics Research Centre, National Research Council Canada, 100 Sussex Drive, Ottawa, ON, K1A 0R6, Canada
| | - Greg Hussack
- Human Health Therapeutics Research Centre, National Research Council Canada, 100 Sussex Drive, Ottawa, ON, K1A 0R6, Canada
| | - Jörg Stetefeld
- Department of Chemistry, University of Manitoba, 144 Dysart Road, Winnipeg, MB, R3T 2N2, Canada
| | - Michael Butler
- Department of Microbiology, University of Manitoba, 144 Dysart Road, Winnipeg, MB, R3T 2N2, Canada
| | - Yves Durocher
- Human Health Therapeutics Research Centre, National Research Council Canada, 6100 Royalmount Ave, Montréal, QC, H4P 2R2, Canada
| | - Jianbing Zhang
- Human Health Therapeutics Research Centre, National Research Council Canada, 100 Sussex Drive, Ottawa, ON, K1A 0R6, Canada
| | - Kevin A Henry
- Human Health Therapeutics Research Centre, National Research Council Canada, 100 Sussex Drive, Ottawa, ON, K1A 0R6, Canada
| | - Jamshid Tanha
- Human Health Therapeutics Research Centre, National Research Council Canada, 100 Sussex Drive, Ottawa, ON, K1A 0R6, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
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36
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Czech A, Konarev PV, Goebel I, Svergun DI, Wills PR, Ignatova Z. Octa-repeat domain of the mammalian prion protein mRNA forms stable A-helical hairpin structure rather than G-quadruplexes. Sci Rep 2019; 9:2465. [PMID: 30792490 PMCID: PMC6384910 DOI: 10.1038/s41598-019-39213-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 12/19/2018] [Indexed: 12/22/2022] Open
Abstract
Misfolding and aggregation of prion protein (PrP) causes neurodegenerative diseases like Creutzfeldt-Jakob disease (CJD) and scrapie. Besides the consensus that spontaneous conversion of normal cellular PrPC into misfolded and aggregating PrPSc is the central event in prion disease, an alternative hypothesis suggests the generation of pathological PrPSc by rare translational frameshifting events in the octa-repeat domain of the PrP mRNA. Ribosomal frameshifting most commonly relies on a slippery site and an adjacent stable RNA structure to stall translating ribosome. Hence, it is crucial to unravel the secondary structure of the octa-repeat domain of PrP mRNA. Each of the five octa-repeats contains a motif (GGCGGUGGUGGCUGGG) which alone in vitro forms a G-quadruplex. Since the propensity of mRNA to form secondary structure depends on the sequence context, we set to determine the structure of the complete octa-repeat region. We assessed the structure of full-length octa-repeat domain of PrP mRNA using dynamic light scattering (DLS), small angle X-ray scattering (SAXS), circular dichroism (CD) spectroscopy and selective 2'-hydroxyl acylation analysis by primer extension (SHAPE). Our data show that the PrP octa-repeat mRNA forms stable A-helical hairpins with no evidence of G-quadruplex structure even in the presence of G-quadruplex stabilizing agents.
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Affiliation(s)
- Andreas Czech
- Institute of Biochemistry and Molecular Biology University of Hamburg, Hamburg, Germany.
| | - Petr V Konarev
- A. V. Shubnikov Institute of Crystallography of Federal Scientific Research Centre "Crystallography and Photonics" of Russian Academy of Sciences, Moscow, Russia
- National Research Centre "Kurchatov Institute", Moscow, Russia
| | - Ingrid Goebel
- Institute of Biochemistry and Molecular Biology University of Hamburg, Hamburg, Germany
| | - Dmitri I Svergun
- European Molecular Biology Laboratory, Hamburg Outstation, c/o DESY, Hamburg, Germany
| | - Peter R Wills
- Department of Physics, University of Auckland, Auckland, New Zealand
| | - Zoya Ignatova
- Institute of Biochemistry and Molecular Biology University of Hamburg, Hamburg, Germany
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37
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Sengar A, Vandana J, Chambers VS, Di Antonio M, Winnerdy F, Balasubramanian S, Phan AT. Structure of a (3+1) hybrid G-quadruplex in the PARP1 promoter. Nucleic Acids Res 2019; 47:1564-1572. [PMID: 30551210 PMCID: PMC6379715 DOI: 10.1093/nar/gky1179] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 11/02/2018] [Accepted: 12/12/2018] [Indexed: 01/08/2023] Open
Abstract
Poly (ADP-ribose) polymerase 1 (PARP1) has emerged as an attractive target for cancer therapy due to its key role in DNA repair processes. Inhibition of PARP1 in BRCA-mutated cancers has been observed to be clinically beneficial. Recent genome-mapping experiments have identified a non-canonical G-quadruplex-forming sequence containing bulges within the PARP1 promoter. Structural features, like bulges, provide opportunities for selective chemical targeting of the non-canonical G-quadruplex structure within the PARP1 promoter, which could serve as an alternative therapeutic approach for the regulation of PARP1 expression. Here we report the G-quadruplex structure formed by a 23-nucleotide G-rich sequence in the PARP1 promoter. Our study revealed a three-layered intramolecular (3+1) hybrid G-quadruplex scaffold, in which three strands are oriented in one direction and the fourth in the opposite direction. This structure exhibits unique structural features such as an adenine bulge and a G·G·T base triple capping structure formed between the central edgewise loop, propeller loop and 5' flanking terminal. Given the highly important role of PARP1 in DNA repair and cancer intervention, this structure presents an attractive opportunity to explore the therapeutic potential of PARP1 inhibition via G-quadruplex DNA targeting.
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Affiliation(s)
- Anjali Sengar
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - J Jeya Vandana
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Vicki S Chambers
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK
| | - Marco Di Antonio
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK
| | - Fernaldo Richtia Winnerdy
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Shankar Balasubramanian
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge CB2 0RE, UK
| | - Anh Tuân Phan
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
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38
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Monsen RC, Trent JO. G-quadruplex virtual drug screening: A review. Biochimie 2018; 152:134-148. [PMID: 29966734 PMCID: PMC6134840 DOI: 10.1016/j.biochi.2018.06.024] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 06/28/2018] [Indexed: 12/18/2022]
Abstract
Over the past two decades biologists and bioinformaticians have unearthed substantial evidence supporting a role for G-quadruplexes as important mediators of biological processes. This includes telomere damage signaling, transcriptional activity, and splicing. Both their structural heterogeneity and their abundance in oncogene promoters makes them ideal targets for drug discovery. Currently, there are hundreds of deposited DNA and RNA quadruplex atomic structures which have allowed researchers to begin using in silico drug screening approaches to develop novel stabilizing ligands. Here we provide a review of the past decade of G-quadruplex virtual drug discovery approaches and campaigns. With this we introduce relevant virtual screening platforms followed by a discussion of best practices to assist future G4 VS campaigns.
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Affiliation(s)
- Robert C Monsen
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, KY, 40206, USA
| | - John O Trent
- James Graham Brown Cancer Center, University of Louisville, Louisville, KY, 40206, USA; Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, KY, 40206, USA; Department of Medicine, University of Louisville, Louisville, KY, 40206, USA.
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39
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Halder D, Purkayastha P. A flavonol that acts as a potential DNA minor groove binder as also an efficient G-quadruplex loop binder. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.05.117] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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