1
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Singh A, Jain N, Shankar U, Sharma TK, Kumar A. Characterization of G-quadruplex structures in genes involved in survival and pathogenesis of Acinetobacter baumannii as a potential drug target. Int J Biol Macromol 2024; 269:131806. [PMID: 38670179 DOI: 10.1016/j.ijbiomac.2024.131806] [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: 12/13/2023] [Revised: 03/21/2024] [Accepted: 03/30/2024] [Indexed: 04/28/2024]
Abstract
Acinetobacter baumannii is a notorious pathogen that commonly thrives in hospital environments and is responsible for numerous nosocomial infections in humans. The burgeoning multi-drug resistance leaves relatively minimal options for treating the bacterial infection, posing a significant problem and prompting the identification of new approaches for tackling the same. This motivated us to focus on non-canonical nucleic acid structures, mainly G-quadruplexes, as drug targets. G-quadruplexes have recently been gaining attention due to their involvement in multiple bacterial and viral pathogenesis. Herein, we sought to explore conserved putative G-quadruplex motifs in A. baumannii. In silico analysis revealed the presence of eight conserved motifs in genes involved in bacterial survival and pathogenesis. The biophysical and biomolecular analysis confirmed stable G-quadruplex formation by the motifs and showed a high binding affinity with the well-reported G-quadruplex binding ligand, BRACO-19. BRACO-19 exposure also decreased the growth of bacteria and downregulated the expression of G-quadruplex-harboring genes. The biofilm-forming ability of the bacteria was also affected by BRACO-19 addition. Taking all these observations into account, we have shown here for the first time the potential of G-quadruplex structures as a promising drug target in Acinetobacter baumannii, for addressing the challenges posed by this infamous pathogen.
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Affiliation(s)
- Aakriti Singh
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India
| | - Neha Jain
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India
| | - Uma Shankar
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India
| | - Tarun Kumar Sharma
- Department of Medical Biotechnology, Gujarat Biotechnology University, Gandhinagar 382355, India
| | - Amit Kumar
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India.
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2
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Orehova M, Plavec J, Kocman V. High-Resolution Structure of RNA G-Quadruplex Containing Unique Structural Motifs Originating from the 5'-UTR of Human Tyrosine Kinase 2 (TYK2). ACS OMEGA 2024; 9:7215-7229. [PMID: 38371751 PMCID: PMC10870306 DOI: 10.1021/acsomega.3c09592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 01/15/2024] [Accepted: 01/22/2024] [Indexed: 02/20/2024]
Abstract
Tyrosine kinase 2 (TYK2) is a member of the JAK family of nonreceptor-associated tyrosine kinases together with highly homologous JAK1, JAK2, and JAK3 paralogues. Overexpression of TYK2 is associated with several inflammatory diseases, including severe complications during the COVID-19 infection. Since the downregulation of JAK paralogues could lead to serious health consequences or even death, it is critical to avoid it when designing drugs to suppress TYK2. To achieve the required specificity only for TYK2, researchers have recently selectively targeted TYK2 mRNA by developing antisense oligonucleotides. In this work, we expand the target space of TYK2 mRNA by showing that the mRNA adopts tetra-helical noncanonical structures called G-quadruplexes. We identified a TYKwt RNA oligonucleotide from the 5'-UTR of TYK2 mRNA, which adopts multiple different parallel G-quadruplexes that exist at equilibrium. Using NMR spectroscopy, we showed that some of the G-quadruplexes adopt unique structural motifs, mainly due to the formation of a stable GA bulge. Using guanine to uridine substitutions, we prepared the oligonucleotide TYK3_U6, which serves as an excellent model for the bulged G-quadruplexes formed by the TYKwt oligonucleotide. NMR structural analysis, including data on the residual coupling constants (RDC) of the loop regions, unveiled that the studied three-quartet parallel G-quadruplex contains many unusual structural features such as a G(U)A bulge, a guanine residue in the syn conformation, A and U residues stacked on the top G-quartet, and a well-defined adenine from a three-residue long propeller loop oriented in the groove, all of which could be valuable targets for future drug design.
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Affiliation(s)
- Maria Orehova
- Slovenian
NMR centre, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
- EN-FIST
Centre of Excellence, Dunajska 156, 1000 Ljubljana, Slovenia
| | - Janez Plavec
- Slovenian
NMR centre, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
- EN-FIST
Centre of Excellence, Dunajska 156, 1000 Ljubljana, Slovenia
- Faculty
of Chemistry and Chemical Technology, University
of Ljubljana, Večna
pot 113, 1000 Ljubljana, Slovenia
| | - Vojč Kocman
- Slovenian
NMR centre, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
- EN-FIST
Centre of Excellence, Dunajska 156, 1000 Ljubljana, Slovenia
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3
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Structural Polymorphism of Guanine Quadruplex-Containing Regions in Human Promoters. Int J Mol Sci 2022; 23:ijms232416020. [PMID: 36555662 PMCID: PMC9786302 DOI: 10.3390/ijms232416020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 12/05/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Intramolecular guanine quadruplexes (G4s) are non-canonical nucleic acid structures formed by four guanine (G)-rich tracts that assemble into a core of stacked planar tetrads. G4-forming DNA sequences are enriched in gene promoters and are implicated in the control of gene expression. Most G4-forming DNA contains more G residues than can simultaneously be incorporated into the core resulting in a variety of different possible G4 structures. Although this kind of structural polymorphism is well recognized in the literature, there remain unanswered questions regarding possible connections between G4 polymorphism and biological function. Here we report a detailed bioinformatic survey of G4 polymorphism in human gene promoter regions. Our analysis is based on identifying G4-containing regions (G4CRs), which we define as stretches of DNA in which every residue can form part of a G4. We found that G4CRs with higher degrees of polymorphism are more tightly clustered near transcription sites and tend to contain G4s with shorter loops and bulges. Furthermore, we found that G4CRs with well-characterized biological functions tended to be longer and more polymorphic than genome-wide averages. These results represent new evidence linking G4 polymorphism to biological function and provide new criteria for identifying biologically relevant G4-forming regions from genomic data.
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4
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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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5
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Grün JT, Schwalbe H. Folding dynamics of polymorphic G-quadruplex structures. Biopolymers 2021; 113:e23477. [PMID: 34664713 DOI: 10.1002/bip.23477] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/30/2021] [Accepted: 09/30/2021] [Indexed: 12/14/2022]
Abstract
G-quadruplexes (G4), found in numerous places within the human genome, are involved in essential processes of cell regulation. Chromosomal DNA G4s are involved for example, in replication and transcription as first steps of gene expression. Hence, they influence a plethora of downstream processes. G4s possess an intricate structure that differs from canonical B-form DNA. Identical DNA G4 sequences can adopt multiple long-lived conformations, a phenomenon known as G4 polymorphism. A detailed understanding of the molecular mechanisms that drive G4 folding is essential to understand their ambivalent regulatory roles. Disentangling the inherent dynamic and polymorphic nature of G4 structures thus is key to unravel their biological functions and make them amenable as molecular targets in novel therapeutic approaches. We here review recent experimental approaches to monitor G4 folding and discuss structural aspects for possible folding pathways. Substantial progress in the understanding of G4 folding within the recent years now allows drawing comprehensive models of the complex folding energy landscape of G4s that we herein evaluate based on computational and experimental evidence.
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Affiliation(s)
- J Tassilo Grün
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University, Frankfurt/M, Germany.,Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University Frankfurt, Frankfurt/M, Germany
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6
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Jana J, Weisz K. Thermodynamic Stability of G-Quadruplexes: Impact of Sequence and Environment. Chembiochem 2021; 22:2848-2856. [PMID: 33844423 PMCID: PMC8518667 DOI: 10.1002/cbic.202100127] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/09/2021] [Indexed: 12/19/2022]
Abstract
G-quadruplexes have attracted growing interest in recent years due to their occurrence in vivo and their possible biological functions. In addition to being promising targets for drug design, these four-stranded nucleic acid structures have also been recognized as versatile tools for various technological applications. Whereas a large number of studies have yielded insight into their remarkable structural diversity, our current knowledge on G-quadruplex stabilities as a function of sequence and environmental factors only gradually emerges with an expanding collection of thermodynamic data. This minireview provides an overview of general rules that may be used to better evaluate quadruplex thermodynamic stabilities but also discusses present challenges in predicting most stable folds for a given sequence and environment.
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Affiliation(s)
- Jagannath Jana
- Institute of BiochemistryUniversität GreifswaldFelix-Hausdorff Str. 417489GreifswaldGermany
| | - Klaus Weisz
- Institute of BiochemistryUniversität GreifswaldFelix-Hausdorff Str. 417489GreifswaldGermany
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7
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Fleming AM, Burrows CJ. Oxidative stress-mediated epigenetic regulation by G-quadruplexes. NAR Cancer 2021; 3:zcab038. [PMID: 34541539 PMCID: PMC8445369 DOI: 10.1093/narcan/zcab038] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/20/2021] [Accepted: 09/06/2021] [Indexed: 02/06/2023] Open
Abstract
Many cancer-associated genes are regulated by guanine (G)-rich sequences that are capable of refolding from the canonical duplex structure to an intrastrand G-quadruplex. These same sequences are sensitive to oxidative damage that is repaired by the base excision repair glycosylases OGG1 and NEIL1–3. We describe studies indicating that oxidation of a guanosine base in a gene promoter G-quadruplex can lead to up- and downregulation of gene expression that is location dependent and involves the base excision repair pathway in which the first intermediate, an apurinic (AP) site, plays a key role mediated by AP endonuclease 1 (APE1/REF1). The nuclease activity of APE1 is paused at a G-quadruplex, while the REF1 capacity of this protein engages activating transcription factors such as HIF-1α, AP-1 and p53. The mechanism has been probed by in vitro biophysical studies, whole-genome approaches and reporter plasmids in cellulo. Replacement of promoter elements by a G-quadruplex sequence usually led to upregulation, but depending on the strand and precise location, examples of downregulation were also found. The impact of oxidative stress-mediated lesions in the G-rich sequence enhanced the effect, whether it was positive or negative.
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Affiliation(s)
- Aaron M Fleming
- Department of Chemistry, University of Utah, 315 S. 1400 East, Salt Lake City, UT 84112-0850, USA
| | - Cynthia J Burrows
- Department of Chemistry, University of Utah, 315 S. 1400 East, Salt Lake City, UT 84112-0850, USA
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8
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Elamri I, Abdellaoui C, Bains JK, Hohmann KF, Gande SL, Stirnal E, Wachtveitl J, Schwalbe H. Wavelength-Selective Uncaging of Two Different Photoresponsive Groups on One Effector Molecule for Light-Controlled Activation and Deactivation. J Am Chem Soc 2021; 143:10596-10603. [PMID: 34236854 DOI: 10.1021/jacs.1c02817] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Photocleavable protecting groups (PPGs) play a pivotal role in numerous studies. They enable controlled release of small effector molecules to induce biochemical function. The number of PPGs attached to a variety of effector molecules has grown rapidly in recent years satisfying the high demand for new applications. However, until now molecules carrying PPGs have been designed to activate function only in a single direction, namely the release of the effector molecule. Herein, we present the new approach Two-PPGs-One-Molecule (TPOM) that exploits the orthogonal photolysis of two photoprotecting groups to first release the effector molecule and then to modify it to suppress its induced effect. The moiety resembling the tyrosyl side chain of the translation inhibitor puromycin was synthetically modified to the photosensitive ortho-nitrophenylalanine that cyclizes upon near UV-irradiation to an inactive puromycin cinnoline derivative. Additionally, the modified puromycin analog was protected by the thio-coumarylmethyl group as the second PPG. This TPOM strategy allows an initial wavelength-selective activation followed by a second light-induced deactivation. Both photolysis processes were spectroscopically studied in the UV/vis- and IR-region. In combination with quantum-chemical calculations and time-resolved NMR spectroscopy, the photoproducts of both activation and deactivation steps upon illumination were characterized. We further probed the translation inhibition effect of the new synthesized puromycin analog upon light activation/deactivation in a cell-free GFP translation assay. TPOM as a new method for precise triggering activation/deactivation of effector molecules represents a valuable addition for the control of biological processes with light.
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Affiliation(s)
- Isam Elamri
- Institute of Organic Chemistry and Chemical Biology, Goethe-University Frankfurt, Frankfurt am Main 60438, Germany
| | - Chahinez Abdellaoui
- Institute of Physical and Theoretical Chemistry, Goethe-University Frankfurt, Frankfurt am Main 60438, Germany
| | - Jasleen Kaur Bains
- Institute of Organic Chemistry and Chemical Biology, Goethe-University Frankfurt, Frankfurt am Main 60438, Germany
| | - Katharina Felicitas Hohmann
- Institute of Organic Chemistry and Chemical Biology, Goethe-University Frankfurt, Frankfurt am Main 60438, Germany
| | - Santosh Lakshmi Gande
- Institute of Organic Chemistry and Chemical Biology, Goethe-University Frankfurt, Frankfurt am Main 60438, Germany
| | - Elke Stirnal
- Institute of Organic Chemistry and Chemical Biology, Goethe-University Frankfurt, Frankfurt am Main 60438, Germany
| | - Josef Wachtveitl
- Institute of Physical and Theoretical Chemistry, Goethe-University Frankfurt, Frankfurt am Main 60438, Germany
| | - Harald Schwalbe
- Institute of Organic Chemistry and Chemical Biology, Goethe-University Frankfurt, Frankfurt am Main 60438, Germany
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9
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Dickerhoff J, Dai J, Yang D. Structural recognition of the MYC promoter G-quadruplex by a quinoline derivative: insights into molecular targeting of parallel G-quadruplexes. Nucleic Acids Res 2021; 49:5905-5915. [PMID: 33978746 PMCID: PMC8191789 DOI: 10.1093/nar/gkab330] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/11/2021] [Accepted: 04/22/2021] [Indexed: 01/21/2023] Open
Abstract
DNA G-Quadruplexes (G4s) formed in oncogene promoters regulate transcription. The oncogene MYC promoter G4 (MycG4) is the most prevalent G4 in human cancers. However, the most studied MycG4 sequence bears a mutated 3′-residue crucial for ligand recognition. Here, we report a new drug-like small molecule PEQ without a large aromatic moiety that specifically binds MycG4. We determined the NMR solution structures of the wild-type MycG4 and its 2:1 PEQ complex, as well as the structure of the 2:1 PEQ complex of the widely used mutant MycG4. Comparison of the two complex structures demonstrates specific molecular recognition of MycG4 and shows the clear effect of the critical 3′-mutation on the drug binding interface. We performed a systematic analysis of the four available complex structures involving the same mutant MycG4, which can be considered a model system for parallel G4s, and revealed for the first time that the flexible flanking residues are recruited in a conserved and sequence-specific way, as well as unused potential for selective ligand-G4 hydrogen-bond interactions. Our results provide the true molecular basis for MycG4-targeting drugs and new critical insights into future rational design of drugs targeting MycG4 and parallel G4s that are prevalent in promoter and RNA G4s.
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Affiliation(s)
- Jonathan Dickerhoff
- Purdue University, College of Pharmacy, Medicinal Chemistry and Molecular Pharmacology, 575 W Stadium Ave., West Lafayette, IN 47907, USA
| | - Jixun Dai
- College of Pharmacy, The University of Arizona, Tucson, AZ 85721, USA
| | - Danzhou Yang
- Purdue University, College of Pharmacy, Medicinal Chemistry and Molecular Pharmacology, 575 W Stadium Ave., West Lafayette, IN 47907, USA.,Purdue University Center for Cancer Research, 201 S University St, West Lafayette, IN 47906, USA.,Purdue University, Department of Chemistry, West Lafayette, IN, USA.,Purdue Institute for Drug Discovery, West Lafayette, IN, USA
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10
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Conformer Analysis of a Biological G-Quadruplex Element in the Human c-MYC Promoter by Native Polyacrylamide Gel Electrophoresis. JOURNAL OF ANALYSIS AND TESTING 2021. [DOI: 10.1007/s41664-021-00181-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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11
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Carrino S, Hennecker CD, Murrieta AC, Mittermaier A. Frustrated folding of guanine quadruplexes in telomeric DNA. Nucleic Acids Res 2021; 49:3063-3076. [PMID: 33693924 PMCID: PMC8034632 DOI: 10.1093/nar/gkab140] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 01/22/2021] [Accepted: 02/19/2021] [Indexed: 11/23/2022] Open
Abstract
Human chromosomes terminate in long, single-stranded, DNA overhangs of the repetitive sequence (TTAGGG)n. Sets of four adjacent TTAGGG repeats can fold into guanine quadruplexes (GQ), four-stranded structures that are implicated in telomere maintenance and cell immortalization and are targets in cancer therapy. Isolated GQs have been studied in detail, however much less is known about folding in long repeat sequences. Such chains adopt an enormous number of configurations containing various arrangements of GQs and unfolded gaps, leading to a highly frustrated energy landscape. To better understand this phenomenon, we used mutagenesis, thermal melting, and global analysis to determine stability, kinetic, and cooperativity parameters for GQ folding within chains containing 8–12 TTAGGG repeats. We then used these parameters to simulate the folding of 32-repeat chains, more representative of intact telomeres. We found that a combination of folding frustration and negative cooperativity between adjacent GQs increases TTAGGG unfolding by up to 40-fold, providing an abundance of unfolded gaps that are potential binding sites for telomeric proteins. This effect was most pronounced at the chain termini, which could promote telomere extension by telomerase. We conclude that folding frustration is an important and largely overlooked factor controlling the structure of telomeric DNA.
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Affiliation(s)
- Simone Carrino
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, H3A 0B8, Canada
| | - Christopher D Hennecker
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, H3A 0B8, Canada
| | - Ana C Murrieta
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, H3A 0B8, Canada.,School of Engineering and Sciences, Instituto Tecnológico y de Estudios Superiores De Monterrey, Av. Eugenio Garza Sada 2501 Sur Col. Tecnológico C.P. 64849, Monterrey, Nuevo León, México
| | - Anthony Mittermaier
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, H3A 0B8, Canada
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12
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Pintér G, Hohmann K, Grün J, Wirmer-Bartoschek J, Glaubitz C, Fürtig B, Schwalbe H. Real-time nuclear magnetic resonance spectroscopy in the study of biomolecular kinetics and dynamics. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2021; 2:291-320. [PMID: 37904763 PMCID: PMC10539803 DOI: 10.5194/mr-2-291-2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 04/07/2021] [Indexed: 11/01/2023]
Abstract
The review describes the application of nuclear magnetic resonance (NMR) spectroscopy to study kinetics of folding, refolding and aggregation of proteins, RNA and DNA. Time-resolved NMR experiments can be conducted in a reversible or an irreversible manner. In particular, irreversible folding experiments pose large requirements for (i) signal-to-noise due to the time limitations and (ii) synchronising of the refolding steps. Thus, this contribution discusses the application of methods for signal-to-noise increases, including dynamic nuclear polarisation, hyperpolarisation and photo-CIDNP for the study of time-resolved NMR studies. Further, methods are reviewed ranging from pressure and temperature jump, light induction to rapid mixing to induce rapidly non-equilibrium conditions required to initiate folding.
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Affiliation(s)
- György Pintér
- Institute for Organic Chemistry and Chemical Biology, Center for
Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang
Goethe-Universität Frankfurt, Frankfurt 60438, Germany
| | - Katharina F. Hohmann
- Institute for Organic Chemistry and Chemical Biology, Center for
Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang
Goethe-Universität Frankfurt, Frankfurt 60438, Germany
| | - J. Tassilo Grün
- Institute for Organic Chemistry and Chemical Biology, Center for
Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang
Goethe-Universität Frankfurt, Frankfurt 60438, Germany
| | - Julia Wirmer-Bartoschek
- Institute for Organic Chemistry and Chemical Biology, Center for
Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang
Goethe-Universität Frankfurt, Frankfurt 60438, Germany
| | - Clemens Glaubitz
- Institute for Biophysical Chemistry, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt 60438, Germany
| | - Boris Fürtig
- Institute for Organic Chemistry and Chemical Biology, Center for
Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang
Goethe-Universität Frankfurt, Frankfurt 60438, Germany
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology, Center for
Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang
Goethe-Universität Frankfurt, Frankfurt 60438, Germany
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13
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Grün JT, Blümler A, Burkhart I, Wirmer-Bartoschek J, Heckel A, Schwalbe H. Unraveling the Kinetics of Spare-Tire DNA G-Quadruplex Folding. J Am Chem Soc 2021; 143:6185-6193. [PMID: 33872503 DOI: 10.1021/jacs.1c01089] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The folding of DNA G-quadruplexes (G4) is essential to regulate expression of oncogenes and involves polymorphic long-lived intermediate states. G4 formation requires four G-tracts, but human gene-promoters often contain multiple G-tracts that act as spare-tires. These additional G-tracts are highly conserved and add multiple layers of functional complexity, as they are crucial to maintain G4 function after oxidative damage. Herein, we unravel the folding dynamics of the G4 sequence containing five G-tracts from cMYC, the major proliferation-driving oncogene. We devise a general method to induce folding at constant experimental conditions using a photochemical trapping strategy. Our data dissect the individual kinetics and thermodynamics of the spare-tire mechanism of cMYC-G4.
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Affiliation(s)
- J Tassilo Grün
- Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt am Main, Frankfurt 60323, Germany.,Center of Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt am Main, Frankfurt 60323, Germany
| | - Anja Blümler
- Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt am Main, Frankfurt 60323, Germany
| | - Ines Burkhart
- Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt am Main, Frankfurt 60323, Germany.,Center of Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt am Main, Frankfurt 60323, Germany
| | - Julia Wirmer-Bartoschek
- Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt am Main, Frankfurt 60323, Germany.,Center of Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt am Main, Frankfurt 60323, Germany
| | - Alexander Heckel
- Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt am Main, Frankfurt 60323, Germany
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt am Main, Frankfurt 60323, Germany.,Center of Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt am Main, Frankfurt 60323, Germany
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14
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Liu B, Shi H, Al-Hashimi HM. Developments in solution-state NMR yield broader and deeper views of the dynamic ensembles of nucleic acids. Curr Opin Struct Biol 2021; 70:16-25. [PMID: 33836446 DOI: 10.1016/j.sbi.2021.02.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 02/20/2021] [Indexed: 12/21/2022]
Abstract
Nucleic acids do not fold into a single conformation, and dynamic ensembles are needed to describe their propensities to cycle between different conformations when performing cellular functions. We review recent advances in solution-state nuclear magnetic resonance (NMR) methods and their integration with computational techniques that are improving the ability to probe the dynamic ensembles of DNA and RNA. These include computational approaches for predicting chemical shifts from structure and generating conformational libraries from sequence, measurements of exact nuclear Overhauser effects, development of new probes to study chemical exchange using relaxation dispersion, faster and more sensitive real-time NMR techniques, and new NMR approaches to tackle large nucleic acid assemblies. We discuss how these advances are leading to new mechanistic insights into gene expression and regulation.
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Affiliation(s)
- Bei Liu
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Honglue Shi
- Department of Chemistry, Duke University, Durham, NC, USA
| | - Hashim M Al-Hashimi
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA; Department of Chemistry, Duke University, Durham, NC, USA.
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15
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Harkness RW, Hennecker C, Grün JT, Blümler A, Heckel A, Schwalbe H, Mittermaier AK. Parallel reaction pathways accelerate folding of a guanine quadruplex. Nucleic Acids Res 2021; 49:1247-1262. [PMID: 33469659 PMCID: PMC7897495 DOI: 10.1093/nar/gkaa1286] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 12/21/2020] [Accepted: 12/27/2020] [Indexed: 02/07/2023] Open
Abstract
G-quadruplexes (G4s) are four-stranded, guanine-rich nucleic acid structures that can influence a variety of biological processes such as the transcription and translation of genes and DNA replication. In many cases, a single G4-forming nucleic acid sequence can adopt multiple different folded conformations that interconvert on biologically relevant timescales, entropically stabilizing the folded state. The coexistence of different folded conformations also suggests that there are multiple pathways leading from the unfolded to the folded state ensembles, potentially modulating the folding rate and biological activity. We have developed an experimental method for quantifying the contributions of individual pathways to the folding of conformationally heterogeneous G4s that is based on mutagenesis, thermal hysteresis kinetic experiments and global analysis, and validated our results using photocaged kinetic NMR experiments. We studied the regulatory Pu22 G4 from the c-myc oncogene promoter, which adopts at least four distinct folded isomers. We found that the presence of four parallel pathways leads to a 2.5-fold acceleration in folding; that is, the effective folding rate from the unfolded to folded ensembles is 2.5 times as large as the rate constant for the fastest individual pathway. Since many G4 sequences can adopt many more than four isomers, folding accelerations of more than an order of magnitude are possible via this mechanism.
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Affiliation(s)
- Robert W Harkness
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada.,Department of Chemistry, McGill University, Montreal, QC H3A 0B8, Canada
| | | | - J Tassilo Grün
- Institute for Organic Chemistry and Chemical Biology, Goethe University, Frankfurt am Main 60438, Germany.,Center of Biomolecular Magnetic Resonance (BMRZ), Goethe University, Frankfurt am Main 60438, Germany
| | - Anja Blümler
- Institute for Organic Chemistry and Chemical Biology, Goethe University, Frankfurt am Main 60438, Germany
| | - Alexander Heckel
- Institute for Organic Chemistry and Chemical Biology, Goethe University, Frankfurt am Main 60438, Germany
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology, Goethe University, Frankfurt am Main 60438, Germany.,Center of Biomolecular Magnetic Resonance (BMRZ), Goethe University, Frankfurt am Main 60438, Germany
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16
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Stadlbauer P, Islam B, Otyepka M, Chen J, Monchaud D, Zhou J, Mergny JL, Šponer J. Insights into G-Quadruplex-Hemin Dynamics Using Atomistic Simulations: Implications for Reactivity and Folding. J Chem Theory Comput 2021; 17:1883-1899. [PMID: 33533244 DOI: 10.1021/acs.jctc.0c01176] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Guanine quadruplex nucleic acids (G4s) are involved in key biological processes such as replication or transcription. Beyond their biological relevance, G4s find applications as biotechnological tools since they readily bind hemin and enhance its peroxidase activity, creating a G4-DNAzyme. The biocatalytic properties of G4-DNAzymes have been thoroughly studied and used for biosensing purposes. Despite hundreds of applications and massive experimental efforts, the atomistic details of the reaction mechanism remain unclear. To help select between the different hypotheses currently under investigation, we use extended explicit-solvent molecular dynamics (MD) simulations to scrutinize the G4/hemin interaction. We find that besides the dominant conformation in which hemin is stacked atop the external G-quartets, hemin can also transiently bind to the loops and be brought to the external G-quartets through diverse delivery mechanisms. The simulations do not support the catalytic mechanism relying on a wobbling guanine. Similarly, the catalytic role of the iron-bound water molecule is not in line with our results; however, given the simulation limitations, this observation should be considered with some caution. The simulations rather suggest tentative mechanisms in which the external G-quartet itself could be responsible for the unique H2O2-promoted biocatalytic properties of the G4/hemin complexes. Once stacked atop a terminal G-quartet, hemin rotates about its vertical axis while readily sampling shifted geometries where the iron transiently contacts oxygen atoms of the adjacent G-quartet. This dynamics is not apparent from the ensemble-averaged structure. We also visualize transient interactions between the stacked hemin and the G4 loops. Finally, we investigated interactions between hemin and on-pathway folding intermediates of the parallel-stranded G4 fold. The simulations suggest that hemin drives the folding of parallel-stranded G4s from slip-stranded intermediates, acting as a G4 chaperone. Limitations of the MD technique are briefly discussed.
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Affiliation(s)
- Petr Stadlbauer
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic
| | - Barira Islam
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic
| | - Michal Otyepka
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic.,Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute, Palacký University, Křížkovského 8, 779 00 Olomouc, Czech Republic
| | - Jielin Chen
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - David Monchaud
- Institut de Chimie Moléculaire (ICMUB), CNRS UMR6302, UBFC, Dijon 21078, France
| | - Jun Zhou
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Jean-Louis Mergny
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic.,State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering, Nanjing University, Nanjing 210023, China.,Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS, INSERM, Institut Polytechnique de Paris, 91128 Palaiseau cedex, France
| | - Jiří Šponer
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic
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17
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Reddy Sannapureddi RK, Mohanty MK, Gautam AK, Sathyamoorthy B. Characterization of DNA G-quadruplex Topologies with NMR Chemical Shifts. J Phys Chem Lett 2020; 11:10016-10022. [PMID: 33179931 DOI: 10.1021/acs.jpclett.0c02969] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
G-quadruplexes are nucleic acid motifs formed by stacking of guanosine-tetrad pseudoplanes. They perform varied biological roles, and their distinctive structural features enable diverse applications. High-resolution structural characterization of G-quadruplexes is often time-consuming and expensive, calling for effective methods. Herein, we develop NMR chemical shifts and machine learning-based methodology that allows direct, rapid, and reliable analysis of canonical three-plane DNA G-quadruplexes sans isotopic enrichment. We show, for the first time, that each unique topology enforces a specific distribution of glycosidic torsion angles. Newly acquired carbon chemical shifts are exquisite probes for the dihedral angle distribution and provide immediate and unambiguous backbone topology assignment. The support vector machine learning methodology aids resonance assignment by providing plane indices for tetrad-forming guanosines. We further demonstrate the robustness by successful application of the methodology to a sequence that folds in two dissimilar topologies under different ionic conditions, providing its first atomic-level characterization.
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Affiliation(s)
| | - Manish Kumar Mohanty
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Madhya Pradesh 462066, India
| | - Anoop Kumar Gautam
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Madhya Pradesh 462066, India
| | - Bharathwaj Sathyamoorthy
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Madhya Pradesh 462066, India
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18
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Jana J, Weisz K. A Thermodynamic Perspective on Potential G-Quadruplex Structures as Silencer Elements in the MYC Promoter. Chemistry 2020; 26:17242-17251. [PMID: 32761687 PMCID: PMC7839732 DOI: 10.1002/chem.202002985] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/31/2020] [Indexed: 01/10/2023]
Abstract
Multiple G‐tracts within the promoter region of the c‐myc oncogene may fold into various G‐quadruplexes with the recruitment of different tracts and guanosine residues for the G‐core assembly. Thermodynamic profiles for the folding of wild‐type and representative truncated as well as mutated sequences were extracted by comprehensive DSC experiments. The unique G‐quadruplex involving consecutive G‐tracts II–V with formation of two one‐nucleotide and one central two‐nucleotide propeller loop, previously proposed to be the biologically most relevant species, was found to be the most stable fold in terms of its Gibbs free energy of formation at ambient temperatures. Its stability derives from its short propeller loops but also from the favorable type of loop residues. Whereas quadruplex folds with long propeller loops are significantly disfavored, a snap‐back loop structure formed by incorporating a 3’‐terminal guanosine into the empty position of a tetrad seems highly competitive based on its thermodynamic stability. However, its destabilization by extending the 3’‐terminus questions the significance of such a species under in vivo conditions.
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Affiliation(s)
- Jagannath Jana
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Str. 4, 17487, Greifswald, Germany
| | - Klaus Weisz
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Str. 4, 17487, Greifswald, Germany
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19
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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: 54] [Impact Index Per Article: 13.5] [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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20
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Oh KI, Kim J, Park CJ, Lee JH. Dynamics Studies of DNA with Non-canonical Structure Using NMR Spectroscopy. Int J Mol Sci 2020; 21:E2673. [PMID: 32290457 PMCID: PMC7216225 DOI: 10.3390/ijms21082673] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/07/2020] [Accepted: 04/09/2020] [Indexed: 12/11/2022] Open
Abstract
The non-canonical structures of nucleic acids are essential for their diverse functions during various biological processes. These non-canonical structures can undergo conformational exchange among multiple structural states. Data on their dynamics can illustrate conformational transitions that play important roles in folding, stability, and biological function. Here, we discuss several examples of the non-canonical structures of DNA focusing on their dynamic characterization by NMR spectroscopy: (1) G-quadruplex structures and their complexes with target proteins; (2) i-motif structures and their complexes with proteins; (3) triplex structures; (4) left-handed Z-DNAs and their complexes with various Z-DNA binding proteins. This review provides insight into how the dynamic features of non-canonical DNA structures contribute to essential biological processes.
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Affiliation(s)
- Kwang-Im Oh
- Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam 52828, Korea;
| | - Jinwoo Kim
- Department of Chemistry, Gwangju Institute of Science and Technology, Gwangju 61005, Korea;
| | - Chin-Ju Park
- Department of Chemistry, Gwangju Institute of Science and Technology, Gwangju 61005, Korea;
| | - Joon-Hwa Lee
- Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam 52828, Korea;
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21
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Molecular dynamics simulations of G-quadruplexes: The basic principles and their application to folding and ligand binding. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 2020. [DOI: 10.1016/bs.armc.2020.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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