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Heel SV, Juen F, Bartosik K, Micura R, Kreutz C, Breuker K. Resolving the intricate binding of neomycin B to multiple binding motifs of a neomycin-sensing riboswitch aptamer by native top-down mass spectrometry and NMR spectroscopy. Nucleic Acids Res 2024; 52:4691-4701. [PMID: 38567725 PMCID: PMC11077050 DOI: 10.1093/nar/gkae224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 03/05/2024] [Accepted: 03/25/2024] [Indexed: 05/09/2024] Open
Abstract
Understanding small molecule binding to RNA can be complicated by an intricate interplay between binding stoichiometry, multiple binding motifs, different occupancies of different binding motifs, and changes in the structure of the RNA under study. Here, we use native top-down mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy to experimentally resolve these factors and gain a better understanding of the interactions between neomycin B and the 40 nt aptamer domain of a neomycin-sensing riboswitch engineered in yeast. Data from collisionally activated dissociation of the 1:1, 1:2 and 1:3 RNA-neomycin B complexes identified a third binding motif C of the riboswitch in addition to the two motifs A and B found in our previous study, and provided occupancies of the different binding motifs for each complex stoichiometry. Binding of a fourth neomycin B molecule was unspecific according to both MS and NMR data. Intriguingly, all major changes in the aptamer structure can be induced by the binding of the first neomycin B molecule regardless of whether it binds to motif A or B as evidenced by stoichiometry-resolved MS data together with titration data from 1H NMR spectroscopy in the imino proton region. Specific binding of the second and third neomycin B molecules further stabilizes the riboswitch aptamer, thereby allowing for a gradual response to increasing concentrations of neomycin B, which likely leads to a fine-tuning of the cellular regulatory mechanism.
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Affiliation(s)
- Sarah Viola Heel
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Fabian Juen
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Karolina Bartosik
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Ronald Micura
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Christoph Kreutz
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Kathrin Breuker
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
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2
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Heel SV, Bartosik K, Juen F, Kreutz C, Micura R, Breuker K. Native Top-Down Mass Spectrometry Uncovers Two Distinct Binding Motifs of a Functional Neomycin-Sensing Riboswitch Aptamer. J Am Chem Soc 2023. [PMID: 37420313 PMCID: PMC10360057 DOI: 10.1021/jacs.3c02774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/09/2023]
Abstract
Understanding how ligands bind to ribonucleic acids (RNA) is important for understanding RNA recognition in biological processes and drug development. Here, we have studied neomycin B binding to neomycin-sensing riboswitch aptamer constructs by native top-down mass spectrometry (MS) using electrospray ionization (ESI) and collisionally activated dissociation (CAD). Our MS data for a 27 nt aptamer construct reveal the binding site and ligand interactions, in excellent agreement with the structure derived from nuclear magnetic resonance (NMR) studies. Strikingly, for an extended 40 nt aptamer construct, which represents the sequence with the highest regulatory factor for riboswitch function, we identified two binding motifs for neomycin B binding, one corresponding to the bulge-loop motif of the 27 nt construct and the other one in the minor groove of the lower stem, which according to the MS data are equally populated. By replacing a noncanonical with a canonical base pair in the lower stem of the 40 nt aptamer, we can reduce binding to the minor groove motif from ∼50 to ∼30%. Conversely, the introduction of a CUG/CUG motif in the lower stem shifts the binding equilibrium in favor of minor groove binding. The MS data reveal site-specific and stoichiometry-resolved information on aminoglycoside binding to RNA that is not directly accessible by other methods and underscore the role of noncanonical base pairs in RNA recognition by aminoglycosides.
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Affiliation(s)
- Sarah Viola Heel
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Karolina Bartosik
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Fabian Juen
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Christoph Kreutz
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Ronald Micura
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Kathrin Breuker
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
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3
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Kenderdine T, Fabris D. The multifaceted roles of mass spectrometric analysis in nucleic acids drug discovery and development. MASS SPECTROMETRY REVIEWS 2023; 42:1332-1357. [PMID: 34939674 PMCID: PMC9218015 DOI: 10.1002/mas.21766] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 09/23/2021] [Accepted: 11/22/2021] [Indexed: 06/07/2023]
Abstract
The deceptively simple concepts of mass determination and fragment analysis are the basis for the application of mass spectrometry (MS) to a boundless range of analytes, including fundamental components and polymeric forms of nucleic acids (NAs). This platform affords the intrinsic ability to observe first-hand the effects of NA-active drugs on the chemical structure, composition, and conformation of their targets, which might affect their ability to interact with cognate NAs, proteins, and other biomolecules present in a natural environment. The possibility of interfacing with high-performance separation techniques represents a multiplying factor that extends these capabilities to cover complex sample mixtures obtained from organisms that were exposed to NA-active drugs. This report provides a brief overview of these capabilities in the context of the analysis of the products of NA-drug activity and NA therapeutics. The selected examples offer proof-of-principle of the applicability of this platform to all phases of the journey undertaken by any successful NA drug from laboratory to bedside, and provide the rationale for its rapid expansion outside traditional laboratory settings in support to ever growing manufacturing operations.
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Affiliation(s)
| | - Dan Fabris
- Department of Chemistry, University of Connecticut
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4
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Deschamps E, Calabrese V, Schmitz I, Hubert-Roux M, Castagnos D, Afonso C. Advances in Ultra-High-Resolution Mass Spectrometry for Pharmaceutical Analysis. Molecules 2023; 28:2061. [PMID: 36903305 PMCID: PMC10003995 DOI: 10.3390/molecules28052061] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/16/2023] [Accepted: 02/19/2023] [Indexed: 02/25/2023] Open
Abstract
Pharmaceutical analysis refers to an area of analytical chemistry that deals with active compounds either by themselves (drug substance) or when formulated with excipients (drug product). In a less simplistic way, it can be defined as a complex science involving various disciplines, e.g., drug development, pharmacokinetics, drug metabolism, tissue distribution studies, and environmental contamination analyses. As such, the pharmaceutical analysis covers drug development to its impact on health and the environment. Moreover, due to the need for safe and effective medications, the pharmaceutical industry is one of the most heavily regulated sectors of the global economy. For this reason, powerful analytical instrumentation and efficient methods are required. In the last decades, mass spectrometry has been increasingly used in pharmaceutical analysis both for research aims and routine quality controls. Among different instrumental setups, ultra-high-resolution mass spectrometry with Fourier transform instruments, i.e., Fourier transform ion cyclotron resonance (FTICR) and Orbitrap, gives access to valuable molecular information for pharmaceutical analysis. In fact, thanks to their high resolving power, mass accuracy, and dynamic range, reliable molecular formula assignments or trace analysis in complex mixtures can be obtained. This review summarizes the principles of the two main types of Fourier transform mass spectrometers, and it highlights applications, developments, and future perspectives in pharmaceutical analysis.
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Affiliation(s)
- Estelle Deschamps
- Normandie Univ, COBRA, UMR 6014 and FR 3038, Université de Rouen, INSA de Rouen, CNRS, IRCOF, 1 rue Tesnières, CEDEX, 76821 Mont-Saint-Aignan, France
- ORIL Industrie, Servier Group, 13 r Auguste Desgenétais, 76210 Bolbec, France
| | - Valentina Calabrese
- Normandie Univ, COBRA, UMR 6014 and FR 3038, Université de Rouen, INSA de Rouen, CNRS, IRCOF, 1 rue Tesnières, CEDEX, 76821 Mont-Saint-Aignan, France
- Université de Lyon, Université Claude Bernard Lyon 1, Institut des Sciences Analytiques, CNRS UMR 5280, 5 Rue de La Doua, F-69100 Villeurbanne, France
| | - Isabelle Schmitz
- Normandie Univ, COBRA, UMR 6014 and FR 3038, Université de Rouen, INSA de Rouen, CNRS, IRCOF, 1 rue Tesnières, CEDEX, 76821 Mont-Saint-Aignan, France
| | - Marie Hubert-Roux
- Normandie Univ, COBRA, UMR 6014 and FR 3038, Université de Rouen, INSA de Rouen, CNRS, IRCOF, 1 rue Tesnières, CEDEX, 76821 Mont-Saint-Aignan, France
| | - Denis Castagnos
- ORIL Industrie, Servier Group, 13 r Auguste Desgenétais, 76210 Bolbec, France
| | - Carlos Afonso
- Normandie Univ, COBRA, UMR 6014 and FR 3038, Université de Rouen, INSA de Rouen, CNRS, IRCOF, 1 rue Tesnières, CEDEX, 76821 Mont-Saint-Aignan, France
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5
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Sosic A, Olivato G, Carraro C, Göttlich R, Fabris D, Gatto B. In Vitro Evaluation of Bis-3-Chloropiperidines as RNA Modulators Targeting TAR and TAR-Protein Interaction. Int J Mol Sci 2022; 23:ijms23020582. [PMID: 35054766 PMCID: PMC8776071 DOI: 10.3390/ijms23020582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 01/01/2022] [Accepted: 01/04/2022] [Indexed: 12/04/2022] Open
Abstract
After a long limbo, RNA has gained its credibility as a druggable target, fully earning its deserved role in the next generation of pharmaceutical R&D. We have recently probed the trans-activation response (TAR) element, an RNA stem–bulge–loop domain of the HIV-1 genome with bis-3-chloropiperidines (B-CePs), and revealed the compounds unique behavior in stabilizing TAR structure, thus impairing in vitro the chaperone activity of the HIV-1 nucleocapsid (NC) protein. Seeking to elucidate the determinants of B-CePs inhibition, we have further characterized here their effects on the target TAR and its NC recognition, while developing quantitative analytical approaches for the study of multicomponent RNA-based interactions.
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Affiliation(s)
- Alice Sosic
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Via Francesco Marzolo 5, 35131 Padova, Italy; (A.S.); (G.O.); (C.C.)
| | - Giulia Olivato
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Via Francesco Marzolo 5, 35131 Padova, Italy; (A.S.); (G.O.); (C.C.)
| | - Caterina Carraro
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Via Francesco Marzolo 5, 35131 Padova, Italy; (A.S.); (G.O.); (C.C.)
| | - Richard Göttlich
- Institute of Organic Chemistry, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany;
| | - Dan Fabris
- Department of Chemistry, University of Connecticut, 55 North Eagleville Rd., Storrs, CT 06269, USA;
| | - Barbara Gatto
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Via Francesco Marzolo 5, 35131 Padova, Italy; (A.S.); (G.O.); (C.C.)
- Correspondence:
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6
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Largy E, König A, Ghosh A, Ghosh D, Benabou S, Rosu F, Gabelica V. Mass Spectrometry of Nucleic Acid Noncovalent Complexes. Chem Rev 2021; 122:7720-7839. [PMID: 34587741 DOI: 10.1021/acs.chemrev.1c00386] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nucleic acids have been among the first targets for antitumor drugs and antibiotics. With the unveiling of new biological roles in regulation of gene expression, specific DNA and RNA structures have become very attractive targets, especially when the corresponding proteins are undruggable. Biophysical assays to assess target structure as well as ligand binding stoichiometry, affinity, specificity, and binding modes are part of the drug development process. Mass spectrometry offers unique advantages as a biophysical method owing to its ability to distinguish each stoichiometry present in a mixture. In addition, advanced mass spectrometry approaches (reactive probing, fragmentation techniques, ion mobility spectrometry, ion spectroscopy) provide more detailed information on the complexes. Here, we review the fundamentals of mass spectrometry and all its particularities when studying noncovalent nucleic acid structures, and then review what has been learned thanks to mass spectrometry on nucleic acid structures, self-assemblies (e.g., duplexes or G-quadruplexes), and their complexes with ligands.
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Affiliation(s)
- Eric Largy
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Alexander König
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Anirban Ghosh
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Debasmita Ghosh
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Sanae Benabou
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Frédéric Rosu
- Univ. Bordeaux, CNRS, INSERM, IECB, UMS 3033, F-33600 Pessac, France
| | - Valérie Gabelica
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
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7
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Sosic A, Göttlich R, Fabris D, Gatto B. B-CePs as cross-linking probes for the investigation of RNA higher-order structure. Nucleic Acids Res 2021; 49:6660-6672. [PMID: 34125908 PMCID: PMC8266612 DOI: 10.1093/nar/gkab468] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 05/13/2021] [Accepted: 05/19/2021] [Indexed: 11/12/2022] Open
Abstract
Elucidating the structure of RNA and RNA ensembles is essential to understand biological functions. In this work, we explored the previously uncharted reactivity of bis-chloropiperidines (B-CePs) towards RNA. We characterized at the molecular level the different adducts induced by the fast reacting compound B-CeP 1 with RNA. Following an approach based on solution thermal melting coupled with ESI mass spectrometry (STHEM-ESI), we proved the ability of B-CePs to induce inter-molecular cross-links between guanines in double stranded RNA. These results open the possibility of using B-CePs as structural probes for investigating higher-order structures, such as the kissing loop complex established by the dimerization initiation site (DIS) of the HIV-1 genome. We confirmed the potential of B-CePs to reveal the identity of RNA structures involved in long-range interactions, expecting to benefit the characterization of samples that are not readily amenable to traditional high-resolution techniques, and thus promoting the elucidation of pertinent RNA systems associated with old and new diseases.
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Affiliation(s)
- Alice Sosic
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, 35131 Padova, Italy
| | - Richard Göttlich
- Institute of Organic Chemistry, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - Dan Fabris
- Departments of Chemistry and Biological Sciences, University at Albany-SUNY, Albany, NY, 12222, USA
| | - Barbara Gatto
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, 35131 Padova, Italy
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8
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Bis-3-Chloropiperidines Targeting TAR RNA as A Novel Strategy to Impair the HIV-1 Nucleocapsid Protein. Molecules 2021; 26:molecules26071874. [PMID: 33810333 PMCID: PMC8038054 DOI: 10.3390/molecules26071874] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/16/2021] [Accepted: 03/22/2021] [Indexed: 11/16/2022] Open
Abstract
Specific RNA sequences regulate functions essential to life. The Trans-Activation Response element (TAR) is an RNA stem-bulge-loop structure involved in several steps of HIV-1 replication. In this work, we show how RNA targeting can inhibit HIV-1 nucleocapsid (NC), a highly conserved protein known to catalyze nucleic acid melting and strand transfers during reverse transcription. Our RNA targeting strategy consists of the employment of bis-3-chloropiperidines (B-CePs) to impair RNA melting through bifunctional alkylation. Specific interactions between B-CePs and TAR RNA were analytically investigated by gel electrophoresis and mass spectrometry, allowing the elucidation of B-CePs' recognition of TAR, and highlighting an RNA-directed mechanism of protein inhibition. We propose that B-CePs can freeze TAR tridimensional conformation, impairing NC-induced dynamics and finally inhibiting its functions in vitro.
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9
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Dremann DN, Chow CS. The use of electrospray ionization mass spectrometry to monitor RNA-ligand interactions. Methods Enzymol 2020; 623:315-337. [PMID: 31239052 DOI: 10.1016/bs.mie.2019.05.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
RNAs are drawing increasing attention as potential therapeutic targets. A significant challenge in the RNA drug discovery process is identification of compounds that not only disrupt the natural functions of RNA by binding with high affinity, but also do so selectively. Assessing the binding mode of small molecules with RNA is important for understanding how they select their binding site and impart their mechanism of action. A number of complementary assays are often employed for analysis of the binding mode and to determine selectivity. One important technique that gives information about the binding affinity and stoichiometry is electrospray ionization mass spectrometry (ESI MS). More recent methods have also revealed the usefulness of ESI MS in determining the binding loci of small molecules on RNA.
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10
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Gamba E, Sosic A, Saccone I, Magli E, Frecentese F, Gatto B. Multiple in Vitro Inhibition of HIV-1 Proteins by 2,6-Dipeptidyl-anthraquinone Conjugates Targeting the PBS RNA. ACS Med Chem Lett 2020; 11:949-955. [PMID: 32435410 DOI: 10.1021/acsmedchemlett.9b00682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 03/23/2020] [Indexed: 11/28/2022] Open
Abstract
We recently reported a series of 2,6-dipeptidyl-anthraquinone conjugates (AQs) as Trans-Activation Response element (TAR) RNA-binding agents able to inhibit in vitro the HIV-1 nucleocapsid (NC) protein-mediated processes. Because NC is a highly adaptable nucleic acid chaperone assisting several crucial steps along reverse transcription, in this study we investigate the ability of AQs to interact with other virus-derived nucleic acid structures thus potentially inhibiting multiple NC functions. Focusing on the HIV-1 Primer Binding Site (PBS) RNA sequence, we demonstrate that properly substituted dipeptidyl-anthraquinone conjugates efficiently inhibit the NC-mediated primer annealing in the low micromolar range. Similarly, we extended the analysis to the HIV-1 trans-activator of transcription (Tat) peptide, which has been recently shown to mimic the annealer functions of NC upon interacting with the same nucleic acid regulatory sequences. Our results highlight how RNA-targeting agents can act as multimode inhibitors of key viral proteins affecting their chaperone activity in reverse transcription processes.
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Affiliation(s)
- Elia Gamba
- Dipartimento di Scienze del Farmaco, Università di Padova, via Marzolo 5, 35131 Padova, Italy
| | - Alice Sosic
- Dipartimento di Scienze del Farmaco, Università di Padova, via Marzolo 5, 35131 Padova, Italy
| | - Irene Saccone
- Dipartimento di Farmacia, Università degli Studi di Napoli "Federico II", Via D. Montesano 49, 80131 Napoli, Italy
| | - Elisa Magli
- Dipartimento di Farmacia, Università degli Studi di Napoli "Federico II", Via D. Montesano 49, 80131 Napoli, Italy
| | - Francesco Frecentese
- Dipartimento di Farmacia, Università degli Studi di Napoli "Federico II", Via D. Montesano 49, 80131 Napoli, Italy
| | - Barbara Gatto
- Dipartimento di Scienze del Farmaco, Università di Padova, via Marzolo 5, 35131 Padova, Italy
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Paul D, Marchand A, Verga D, Teulade-Fichou MP, Bombard S, Rosu F, Gabelica V. Probing ligand and cation binding sites in G-quadruplex nucleic acids by mass spectrometry and electron photodetachment dissociation sequencing. Analyst 2019; 144:3518-3524. [PMID: 31020955 DOI: 10.1039/c9an00398c] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mass spectrometry provides exquisite details on ligand and cation binding stoichiometries with a DNA target. The next important step is to develop reliable methods to determine the cation and ligand binding sites in each complex separated by using a mass spectrometer. To circumvent the caveat of ligand derivatization for cross-linking, which may alter the ligand binding mode, we explored a tandem mass spectrometry (MS/MS) method that does not require ligand derivatization, and is therefore also applicable to localize metal cations. By putting more negative charge states on the complexes using supercharging agents, and by creating radical ions by electron photodetachment, oligonucleotide bonds become weaker than the DNA-cation or DNA-ligand noncovalent bonds upon collision-induced dissociation of the radicals. This electron photodetachment (EPD) method allows one to locate the binding regions of cations and ligands by top-down sequencing of the oligonucleotide target. The very potent G-quadruplex ligands 360A and PhenDC3 were found to replace a potassium cation and bind close to the central loop of 4-repeat human telomeric sequences.
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Affiliation(s)
- Dababrata Paul
- University of Bordeaux, INSERM and CNRS, ARNA Laboratory, IECB site, 2 rue Robert Escarpit, 33600 Pessac, France.
| | - Adrien Marchand
- University of Bordeaux, INSERM and CNRS, ARNA Laboratory, IECB site, 2 rue Robert Escarpit, 33600 Pessac, France.
| | - Daniela Verga
- Institut Curie, PSL Research University, CNRS-UMR 9187, INSERM U1196, F-91405 Orsay, France and Université Paris Sud, Université Paris-Saclay, CNRS-UMR 9187, INSERM U1196, F-91405 Orsay, France
| | - Marie-Paule Teulade-Fichou
- Institut Curie, PSL Research University, CNRS-UMR 9187, INSERM U1196, F-91405 Orsay, France and Université Paris Sud, Université Paris-Saclay, CNRS-UMR 9187, INSERM U1196, F-91405 Orsay, France
| | - Sophie Bombard
- Institut Curie, PSL Research University, CNRS-UMR 9187, INSERM U1196, F-91405 Orsay, France and Université Paris Sud, Université Paris-Saclay, CNRS-UMR 9187, INSERM U1196, F-91405 Orsay, France
| | - Frédéric Rosu
- CNRS UMS3033, Inserm US001, IECB, 2 rue Robert Escarpit, 33607 Pessac, France.
| | - Valérie Gabelica
- University of Bordeaux, INSERM and CNRS, ARNA Laboratory, IECB site, 2 rue Robert Escarpit, 33600 Pessac, France.
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12
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MS methods to study macromolecule-ligand interaction: Applications in drug discovery. Methods 2018; 144:152-174. [PMID: 29890284 DOI: 10.1016/j.ymeth.2018.06.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 06/01/2018] [Accepted: 06/03/2018] [Indexed: 12/12/2022] Open
Abstract
The interaction of small compounds (i.e. ligands) with macromolecules or macromolecule assemblies (i.e. targets) is the mechanism of action of most of the drugs available today. Mass spectrometry is a popular technique for the interrogation of macromolecule-ligand interactions and therefore is also widely used in drug discovery and development. Thanks to its versatility, mass spectrometry is used for multiple purposes such as biomarker screening, identification of the mechanism of action, ligand structure optimization or toxicity assessment. The evolution and automation of the instruments now allows the development of high throughput methods with high sensitivity and a minimized false discovery rate. Herein, all these approaches are described with a focus on the methods for studying macromolecule-ligand interaction aimed at defining the structure-activity relationships of drug candidates, along with their mechanism of action, metabolism and toxicity.
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13
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Sosic A, Saccone I, Carraro C, Kenderdine T, Gamba E, Caliendo G, Corvino A, Di Vaio P, Fiorino F, Magli E, Perissutti E, Santagada V, Severino B, Spada V, Fabris D, Frecentese F, Gatto B. Non-Natural Linker Configuration in 2,6-Dipeptidyl-Anthraquinones Enhances the Inhibition of TAR RNA Binding/Annealing Activities by HIV-1 NC and Tat Proteins. Bioconjug Chem 2018; 29:2195-2207. [PMID: 29791798 DOI: 10.1021/acs.bioconjchem.8b00104] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The HIV-1 nucleocapsid (NC) protein represents an excellent molecular target for the development of anti-retrovirals by virtue of its well-characterized chaperone activities, which play pivotal roles in essential steps of the viral life cycle. Our ongoing search for candidates able to impair NC binding/annealing activities led to the identification of peptidyl-anthraquinones as a promising class of nucleic acid ligands. Seeking to elucidate the inhibition determinants and increase the potency of this class of compounds, we have now explored the effects of chirality in the linker connecting the planar nucleus to the basic side chains. We show here that the non-natural linker configuration imparted unexpected TAR RNA targeting properties to the 2,6-peptidyl-anthraquinones and significantly enhanced their potency. Even if the new compounds were able to interact directly with the NC protein, they manifested a consistently higher affinity for the TAR RNA substrate and their TAR-binding properties mirrored their ability to interfere with NC-TAR interactions. Based on these findings, we propose that the viral Tat protein, sharing the same RNA substrate but acting in distinct phases of the viral life cycle, constitutes an additional druggable target for this class of peptidyl-anthraquinones. The inhibition of Tat-TAR interaction for the test compounds correlated again with their TAR-binding properties, while simultaneously failing to demonstrate any direct Tat-binding capabilities. These considerations highlighted the importance of TAR RNA in the elucidation of their inhibition mechanism, rather than direct protein inhibition. We have therefore identified anti-TAR compounds with dual in vitro inhibitory activity on different viral proteins, demonstrating that it is possible to develop multitarget compounds capable of interfering with processes mediated by the interactions of this essential RNA domain of HIV-1 genome with NC and Tat proteins.
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Affiliation(s)
- Alice Sosic
- Dipartimento di Scienze del Farmaco , Università di Padova , via Marzolo 5 , 35131 Padova , Italy
| | - Irene Saccone
- Dipartimento di Farmacia , Università degli Studi di Napoli "Federico II" , Via D. Montesano 49 , 80131 Napoli , Italy
| | - Caterina Carraro
- Dipartimento di Scienze del Farmaco , Università di Padova , via Marzolo 5 , 35131 Padova , Italy
| | - Thomas Kenderdine
- The RNA Institute and Department of Chemistry , State University of New York , 1400 Washington Avenue , Albany , New York 12222 , United States
| | - Elia Gamba
- Dipartimento di Scienze del Farmaco , Università di Padova , via Marzolo 5 , 35131 Padova , Italy
| | - Giuseppe Caliendo
- Dipartimento di Farmacia , Università degli Studi di Napoli "Federico II" , Via D. Montesano 49 , 80131 Napoli , Italy
| | - Angela Corvino
- Dipartimento di Farmacia , Università degli Studi di Napoli "Federico II" , Via D. Montesano 49 , 80131 Napoli , Italy
| | - Paola Di Vaio
- Dipartimento di Farmacia , Università degli Studi di Napoli "Federico II" , Via D. Montesano 49 , 80131 Napoli , Italy
| | - Ferdinando Fiorino
- Dipartimento di Farmacia , Università degli Studi di Napoli "Federico II" , Via D. Montesano 49 , 80131 Napoli , Italy
| | - Elisa Magli
- Dipartimento di Farmacia , Università degli Studi di Napoli "Federico II" , Via D. Montesano 49 , 80131 Napoli , Italy
| | - Elisa Perissutti
- Dipartimento di Farmacia , Università degli Studi di Napoli "Federico II" , Via D. Montesano 49 , 80131 Napoli , Italy
| | - Vincenzo Santagada
- Dipartimento di Farmacia , Università degli Studi di Napoli "Federico II" , Via D. Montesano 49 , 80131 Napoli , Italy
| | - Beatrice Severino
- Dipartimento di Farmacia , Università degli Studi di Napoli "Federico II" , Via D. Montesano 49 , 80131 Napoli , Italy
| | - Valentina Spada
- Dipartimento di Farmacia , Università degli Studi di Napoli "Federico II" , Via D. Montesano 49 , 80131 Napoli , Italy
| | - Dan Fabris
- The RNA Institute and Department of Chemistry , State University of New York , 1400 Washington Avenue , Albany , New York 12222 , United States
| | - Francesco Frecentese
- Dipartimento di Farmacia , Università degli Studi di Napoli "Federico II" , Via D. Montesano 49 , 80131 Napoli , Italy
| | - Barbara Gatto
- Dipartimento di Scienze del Farmaco , Università di Padova , via Marzolo 5 , 35131 Padova , Italy
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14
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Vušurović J, Schneeberger E, Breuker K. Interactions of Protonated Guanidine and Guanidine Derivatives with Multiply Deprotonated RNA Probed by Electrospray Ionization and Collisionally Activated Dissociation. ChemistryOpen 2017; 6:739-750. [PMID: 29226062 PMCID: PMC5715244 DOI: 10.1002/open.201700143] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 10/06/2017] [Indexed: 11/25/2022] Open
Abstract
Interactions of ribonucleic acid (RNA) with guanidine and guanidine derivatives are important features in RNA-protein and RNA-drug binding. Here we have investigated noncovalently bound complexes of an 8-nucleotide RNA and six different ligands, all of which have a guanidinium moiety, by using electrospray ionization (ESI) and collisionally activated dissociation (CAD) mass spectrometry (MS). The order of complex stability correlated almost linearly with the number of ligand atoms that can potentially be involved in hydrogen-bond or salt-bridge interactions with the RNA, but not with the proton affinity of the ligands. However, ligand dissociation of the complex ions in CAD was generally accompanied by proton transfer from ligand to RNA, which indicated conversion of salt-bridge into hydrogen-bond interactions. The relative stabilities and dissociation pathways of [RNA+m L-n H] n- complexes with different stoichiometries (m=1-5) and net charge (n= 2-5) revealed both specific and unspecific ligand binding to the RNA.
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Affiliation(s)
- Jovana Vušurović
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI)University of InnsbruckInnrain 80–826020InnsbruckAustria
| | - Eva‐Maria Schneeberger
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI)University of InnsbruckInnrain 80–826020InnsbruckAustria
| | - Kathrin Breuker
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI)University of InnsbruckInnrain 80–826020InnsbruckAustria
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15
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Schneeberger E, Breuker K. Native Top-Down Mass Spectrometry of TAR RNA in Complexes with a Wild-Type tat Peptide for Binding Site Mapping. Angew Chem Int Ed Engl 2017; 56:1254-1258. [PMID: 28000363 PMCID: PMC5299493 DOI: 10.1002/anie.201610836] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Indexed: 12/18/2022]
Abstract
Ribonucleic acids (RNA) frequently associate with proteins in many biological processes to form more or less stable complex structures. The characterization of RNA-protein complex structures and binding interfaces by nuclear magnetic resonance (NMR) spectroscopy, X-ray crystallography, or strategies based on chemical crosslinking, however, can be quite challenging. Herein, we have explored the use of an alternative method, native top-down mass spectrometry (MS), for probing of complex stoichiometry and protein binding sites at the single-residue level of RNA. Our data show that the electrostatic interactions between HIV-1 TAR RNA and a peptide comprising the arginine-rich binding region of tat protein are sufficiently strong in the gas phase to survive phosphodiester backbone cleavage of RNA by collisionally activated dissociation (CAD), thus allowing its use for probing tat binding sites in TAR RNA by top-down MS. Moreover, the MS data reveal time-dependent 1:2 and 1:1 stoichiometries of the TAR-tat complexes and suggest structural rearrangements of TAR RNA induced by binding of tat peptide.
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Affiliation(s)
- Eva‐Maria Schneeberger
- Institut für Organische Chemie and Center for Molecular Biosciences Innsbruck (CMBI)Universität InnsbruckInnrain 80-826020InnsbruckAustria
| | - Kathrin Breuker
- Institut für Organische Chemie and Center for Molecular Biosciences Innsbruck (CMBI)Universität InnsbruckInnrain 80-826020InnsbruckAustria
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16
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Schneeberger E, Breuker K. Native Top‐Down Mass Spectrometry of TAR RNA in Complexes with a Wild‐Type tat Peptide for Binding Site Mapping. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201610836] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Eva‐Maria Schneeberger
- Institut für Organische Chemie and Center for Molecular Biosciences Innsbruck (CMBI) Universität Innsbruck Innrain 80-82 6020 Innsbruck Austria
| | - Kathrin Breuker
- Institut für Organische Chemie and Center for Molecular Biosciences Innsbruck (CMBI) Universität Innsbruck Innrain 80-82 6020 Innsbruck Austria
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17
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Lippens JL, Mangrum J, McIntyre W, Redick B, Fabris D. A simple heated-capillary modification improves the analysis of non-covalent complexes by Z-spray electrospray ionization. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2016; 30:773-83. [PMID: 26864529 PMCID: PMC4868961 DOI: 10.1002/rcm.7490] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 12/11/2015] [Accepted: 12/15/2015] [Indexed: 05/29/2023]
Abstract
RATIONALE The observation of intact non-covalent complexes by electrospray ionization mass spectrometry (ESI-MS) hinges on the ability to minimize in-source activation processes that take place during analyte desolvation. We explored the merits of replacing the sampling cone of a standard Z-spray source with a heated capillary that makes the desolvation process slower and more gradual. We employed well-characterized protein-RNA, RNA-RNA, and DNA-DNA assemblies to compare the alternative configurations. METHODS Mass analysis evaluated the integrity of the complexes, whereas traveling wave ion mobility experiments assessed the stability of biomolecular structure. Analyses were performed back-to-back on the same samples on a Synapt G2 HDMS equipped with either the standard sampling cone or the heated-capillary apparatus. In each configuration, the source/capillary temperature was varied in controlled fashion, while keeping all other desolvation parameters constant to monitor the in-source dissociation of selected DNA duplexes. Ion mobility data were obtained from the same precursor by using the alternative configurations under the same settings. RESULTS Monitoring the percentage of associated complex demonstrated that the heated capillary provided softer desolvation that was more conducive to the detection of intact non-covalent interactions. This configuration failed to produce complete dissociation of 14 bp and 24 bp duplexes, even when the source/capillary temperature was increased well above their solution melting points. Analyzed by IMS-MS, a selected construct displayed just one conformation with the heated capillary, but two with the standard sampling cone. CONCLUSIONS The heated capillary minimizes in-source activation processes that can lead to unintended dissociation of complexes and perturbation of biomolecular structure, which rely on the integrity of non-covalent interactions. This effect can be attributed to the attenuation of the supersonic expansion typical of the Z-spray geometry and the greater ability to control the energy imparted to the system. This hardware modification will be expected to benefit the analysis of biomolecular structure performed on this particular instrumental platform.
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Affiliation(s)
| | | | | | - Bill Redick
- The RNA Institute, University at Albany (SUNY)
| | - D. Fabris
- The RNA Institute, University at Albany (SUNY)
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18
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Frecentese F, Sosic A, Saccone I, Gamba E, Link K, Miola A, Cappellini M, Cattelan MG, Severino B, Fiorino F, Magli E, Corvino A, Perissutti E, Fabris D, Gatto B, Caliendo G, Santagada V. Synthesis and in Vitro Screening of New Series of 2,6-Dipeptidyl-anthraquinones: Influence of Side Chain Length on HIV-1 Nucleocapsid Inhibitors. J Med Chem 2016; 59:1914-24. [PMID: 26797100 DOI: 10.1021/acs.jmedchem.5b01494] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
2,6-Dipeptidyl-anthraquinones are a promising class of nucleic acid-binding compounds that act as NC inhibitors in vitro. We designed, synthesized, and tested new series of 2,6-disubstituted-anthraquinones, which are able to bind viral nucleic acid substrates of NC. We demonstrate here that these novel derivatives interact preferentially with noncanonical structures of TAR and cTAR, stabilize their dynamics, and interfere with NC chaperone activity.
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Affiliation(s)
- Francesco Frecentese
- Dipartimento di Farmacia, Università di Napoli "Federico II" Via D. Montesano 49, 80131 Napoli, Italy
| | - Alice Sosic
- Dipartimento di Scienze del Farmaco, Università di Padova , via Marzolo 5, 35131 Padova, Italy
| | - Irene Saccone
- Dipartimento di Farmacia, Università di Napoli "Federico II" Via D. Montesano 49, 80131 Napoli, Italy
| | - Elia Gamba
- Dipartimento di Scienze del Farmaco, Università di Padova , via Marzolo 5, 35131 Padova, Italy
| | - Kristina Link
- Dipartimento di Scienze del Farmaco, Università di Padova , via Marzolo 5, 35131 Padova, Italy
| | - Angelica Miola
- Dipartimento di Scienze del Farmaco, Università di Padova , via Marzolo 5, 35131 Padova, Italy
| | - Marta Cappellini
- Dipartimento di Scienze del Farmaco, Università di Padova , via Marzolo 5, 35131 Padova, Italy
| | | | - Beatrice Severino
- Dipartimento di Farmacia, Università di Napoli "Federico II" Via D. Montesano 49, 80131 Napoli, Italy
| | - Ferdinando Fiorino
- Dipartimento di Farmacia, Università di Napoli "Federico II" Via D. Montesano 49, 80131 Napoli, Italy
| | - Elisa Magli
- Dipartimento di Farmacia, Università di Napoli "Federico II" Via D. Montesano 49, 80131 Napoli, Italy
| | - Angela Corvino
- Dipartimento di Farmacia, Università di Napoli "Federico II" Via D. Montesano 49, 80131 Napoli, Italy
| | - Elisa Perissutti
- Dipartimento di Farmacia, Università di Napoli "Federico II" Via D. Montesano 49, 80131 Napoli, Italy
| | - Dan Fabris
- The RNA Institute and Department of Chemistry, State University of New York , 1400 Washington Avenue, Albany, New York 12222, United States
| | - Barbara Gatto
- Dipartimento di Scienze del Farmaco, Università di Padova , via Marzolo 5, 35131 Padova, Italy
| | - Giuseppe Caliendo
- Dipartimento di Farmacia, Università di Napoli "Federico II" Via D. Montesano 49, 80131 Napoli, Italy
| | - Vincenzo Santagada
- Dipartimento di Farmacia, Università di Napoli "Federico II" Via D. Montesano 49, 80131 Napoli, Italy
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19
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Sosic A, Sinigaglia L, Cappellini M, Carli I, Parolin C, Zagotto G, Sabatino G, Rovero P, Fabris D, Gatto B. Mechanisms of HIV-1 Nucleocapsid Protein Inhibition by Lysyl-Peptidyl-Anthraquinone Conjugates. Bioconjug Chem 2015; 27:247-56. [PMID: 26666402 DOI: 10.1021/acs.bioconjchem.5b00627] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The Nucleocapsid protein NCp7 (NC) is a nucleic acid chaperone responsible for essential steps of the HIV-1 life cycle and an attractive candidate for drug development. NC destabilizes nucleic acid structures and promotes the formation of annealed substrates for HIV-1 reverse transcription elongation. Short helical nucleic acid segments bordered by bulges and loops, such as the Trans-Activation Response element (TAR) of HIV-1 and its complementary sequence (cTAR), are nucleation elements for helix destabilization by NC and also preferred recognition sites for threading intercalators. Inspired by these observations, we have recently demonstrated that 2,6-disubstituted peptidyl-anthraquinone-conjugates inhibit the chaperone activities of recombinant NC in vitro, and that inhibition correlates with the stabilization of TAR and cTAR stem-loop structures. We describe here enhanced NC inhibitory activity by novel conjugates that exhibit longer peptidyl chains ending with a conserved N-terminal lysine. Their efficient inhibition of TAR/cTAR annealing mediated by NC originates from the combination of at least three different mechanisms, namely, their stabilizing effects on nucleic acids dynamics by threading intercalation, their ability to target TAR RNA substrate leading to a direct competition with the protein for the same binding sites on TAR, and, finally, their effective binding to the NC protein. Our results suggest that these molecules may represent the stepping-stone for the future development of NC-inhibitors capable of targeting the protein itself and its recognition site in RNA.
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Affiliation(s)
| | | | | | | | | | | | | | - Paolo Rovero
- Dipartimento NeuroFarBa, Sezione di Scienze Farmaceutiche e Nutraceutica, Università di Firenze , 50121 Firenze, Italy
| | - Dan Fabris
- Department of Chemistry, State University of New York , Albany, New York 12222, United States
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20
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Riml C, Glasner H, Rodgers MT, Micura R, Breuker K. On the mechanism of RNA phosphodiester backbone cleavage in the absence of solvent. Nucleic Acids Res 2015; 43:5171-81. [PMID: 25904631 PMCID: PMC4446422 DOI: 10.1093/nar/gkv288] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 03/24/2015] [Indexed: 12/18/2022] Open
Abstract
Ribonucleic acid (RNA) modifications play an important role in the regulation of gene expression and the development of RNA-based therapeutics, but their identification, localization and relative quantitation by conventional biochemical methods can be quite challenging. As a promising alternative, mass spectrometry (MS) based approaches that involve RNA dissociation in ‘top-down’ strategies are currently being developed. For this purpose, it is essential to understand the dissociation mechanisms of unmodified and posttranscriptionally or synthetically modified RNA. Here, we have studied the effect of select nucleobase, ribose and backbone modifications on phosphodiester bond cleavage in collisionally activated dissociation (CAD) of positively and negatively charged RNA. We found that CAD of RNA is a stepwise reaction that is facilitated by, but does not require, the presence of positive charge. Preferred backbone cleavage next to adenosine and guanosine in CAD of (M+nH)n+ and (M−nH)n− ions, respectively, is based on hydrogen bonding between nucleobase and phosphodiester moieties. Moreover, CAD of RNA involves an intermediate that is sufficiently stable to survive extension of the RNA structure and intramolecular proton redistribution according to simple Coulombic repulsion prior to backbone cleavage into c and y ions from phosphodiester bond cleavage.
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Affiliation(s)
- Christian Riml
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Heidelinde Glasner
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - M T Rodgers
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI 48202-3489, United States
| | - Ronald Micura
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Kathrin Breuker
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
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21
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Abstract
Nucleic acids are diverse polymeric macromolecules that are essential for all life forms. These biomolecules possess a functional three-dimensional structure under aqueous physiological conditions. Mass spectrometry-based approaches have on the other hand opened the possibility to gain structural information on nucleic acids from gas-phase measurements. To correlate gas-phase structural probing results with solution structures, it is therefore important to grasp the extent to which nucleic acid structures are preserved, or altered, when transferred from the solution to a fully anhydrous environment. We will review here experimental and theoretical approaches available to characterize the structure of nucleic acids in the gas phase (with a focus on oligonucleotides and higher-order structures), and will summarize the structural features of nucleic acids that can be preserved in the gas phase on the experiment time scale.
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22
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Cui X, Lin S, Zhou J, Yuan G. Investigation of non-covalent interaction of natural flexible cyclic molecules with telomeric RNA G-quadruplexes by electrospray ionization mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2012; 26:1803-1809. [PMID: 22777782 DOI: 10.1002/rcm.6295] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
RATIONALE Recently, human telomeric DNA was found to be transcribed into RNA transcripts composing of tandem repeats of r(UUAGGG) which can form G-quadruplex structures. Studies have shown that human telomeric RNA is associated with the telomerase activity in vitro. Finding high affinity small molecule ligands binding to the telomeric RNA G-quadruplex may facilitate the regulation of the telomerase activity. METHODS The 12-mer and 24-mer telomeric RNA sequences, r(UAGGGUUAGGGU) and r(UAGGGUUAGGGUUAGGGUUAGGGU), were synthesized by TaKaRa Biotechnology (Dalian) Co., Ltd. (TaKaRa, Dalian) with high-performance liquid chromatography (HPLC) purification. Electrospray ionization ion-trap mass spectrometry was used to evaluate the binding affinities of three natural flexible cyclic molecules, tetrandrine, fangchinoline and cepharanthine, with the telomeric RNA G-quadruplexes. The fragmentation pathways of the G-quadruplexes and G-quadruplex-ligand complexes were investigated by tandem mass spectrometry. RESULTS the natural flexible cyclic molecules were found to have high binding affinities to the 12-mer and 24-mer RNA G-quadruplexes with stoichiometry of 1:1 to 3:1. Collision-induced dissociation tandem mass spectrometry shows that the G-quadruplex-ligand complexes lose neutral ammoniums first and the small molecule ligand subsequently. Besides, among the three flexible cyclic molecules, cepharanthine binds most tightly to the RNA G-quadruplexes than tetandrine and fangchinoline. CONCLUSIONS Three flexible cyclic small molecules were found to be potential telomeric RNA G-quadruplex ligands, especially cepharanthine, which has high affinity and binds most tightly to the RNA G-quadruplexes. These findings may provide further implications in the regulation of telomeric RNA and telomerase activity.
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Affiliation(s)
- Xiaojie Cui
- Beijing National Laboratory for Molecular Sciences, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
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23
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Fabris D, Kellersberger K, Wilhide J. Higher-order structure of nucleic acids in the gas phase: top-down analysis of base-pairing interactions. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2012; 312:155-162. [PMID: 24027423 PMCID: PMC3767431 DOI: 10.1016/j.ijms.2011.07.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Non-ergodic as well as ergodic activation methods are capable of maintaining the integrity of base pairs during the top-down analysis of nucleic acids. Here, we investigate the significance of this characteristic in the investigation of higher-order structures of increasing complexity. We show that cognate fragments produced by typical backbone cleavages may not be always detected as separate sequence ions, but rather as individual products that remain associated through mutual pairing contacts. This effect translates into unintended masking of cleavage events that take place in double-stranded regions, thus leading to the preferential detection of fragments originating from unpaired regions. Such effect is determined by the stability of the weak non-covalent association between complementary stretches, which is affected by base composition, length of the double-stranded structure, and charge of the precursor ion selected for analysis. Although such effect may prevent the achievement of full sequence coverage for primary structure determination, it may provide the key to correctly differentiate double- versus single-stranded regions, in what could be defined as gas-phase footprinting experiments. In light of the critical role played by base pairs in defining the higher-order structure of nucleic acids, these approaches will be expected to support an increased utilization of mass spectrometry for the investigation of nucleic acid structure and dynamics.
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Affiliation(s)
- D. Fabris
- The RNA Institute, University at Albany
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24
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Cui W, Rohrs HW, Gross ML. Top-down mass spectrometry: recent developments, applications and perspectives. Analyst 2011; 136:3854-64. [PMID: 21826297 PMCID: PMC3505190 DOI: 10.1039/c1an15286f] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Top-down mass spectrometry is an emerging approach for the analysis of intact proteins. The term was coined as a contrast with the better-established, bottom-up strategy for analysis of peptide fragments derived from digestion, either enzymatically or chemically, of intact proteins. Although the term top-down originates from proteomics, it can also be applied to mass spectrometric analysis of intact large biomolecules that are constituents of protein assemblies or complexes. Traditionally, mass spectrometry has usually started with intact molecules, and in this regard, top-down approaches reflect the spirit of mass spectrometry. This article provides an overview of the methodologies in top-down mass spectrometry and then reviews applications covering protein posttranslational modifications, protein biophysics, DNAs/RNAs, and protein assemblies. Finally, challenges and future directions are discussed.
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Affiliation(s)
- Weidong Cui
- NIH NCRR Center for Biomedical and Bio-Organic Mass Spectrometry, Department of Chemistry, Washington University, St. Louis, MO 63130, USA.
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25
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Abstract
Alternative approaches complementing the existing technologies for analysis of nucleic acids and their assemblies are necessary to take on the new challenges posed by the postgenomic era. The versatility of MS in biopolymer analysis and its ability to reach beyond sequence information are the basis of ever expanding applications aimed at the elucidation of nucleic acid structure-function relationships. This Feature summarizes the current state of MS-based approaches devised to overcome the limitations of traditional techniques and to advance different facets of nucleic acids research.
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Affiliation(s)
- D Fabris
- The RNA Institute, University at Albany, Albany, NY 12222, USA.
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26
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Huang TY, Liu J, McLuckey SA. Top-down tandem mass spectrometry of tRNA via ion trap collision-induced dissociation. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2010; 21:890-898. [PMID: 20080046 DOI: 10.1016/j.jasms.2009.12.007] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Revised: 12/15/2009] [Accepted: 12/16/2009] [Indexed: 05/28/2023]
Abstract
Transfer RNA is a class of highly modified and structured non-coding RNA molecules generally comprised of 74-95 nucleotides. In this study, tandem mass spectrometry of intact multiply charged tRNA anions of roughly 25 kDa in mass has been demonstrated using a quadrupole/time-of-flight tandem mass spectrometer adapted for ion/ion reaction studies. The sample proved to be a mixture of tRNA molecules. The mass of the most abundant component of the mixture was not consistent with that of the nominal identity of the tRNA from the supplier, viz., tRNA(Phe); rather, the mass was consistent with tRNA(Phe) bearing an incomplete 3'-terminus. Multiply-charged anions from the major components were isolated in the gas phase and subjected to ion trap collision-induced dissociation without subsequent ion/ion reactions. Abundant fragments from the 5'- and 3'-termini of the molecule could be used to identify the major component as tRNA(Phe)-3'adenosine (without 3'-phosphorylation). Roughly 15% of the primary sequence of the intact tRNA was unambiguously reflected in the product ion spectrum. The existence of a possible tRNA(Phe) variant and the intact tRNA(Phe) was also supported by ion trap CID data. The multiply-charged fragment ions derived from tRNA(Phe)-3'adenosine were further charge-reduced to mostly singly- and doubly-charged species via proton transfer ion/ion reactions with benzoquinoline cations. The resulting reduction in spectral overlap and charge state ambiguity simplified interpretation of the product ion spectrum and allowed for the identification of product ions from roughly 60% of the sequence.
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Affiliation(s)
- Teng-Yi Huang
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
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27
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Taucher M, Breuker K. Top-down mass spectrometry for sequencing of larger (up to 61 nt) RNA by CAD and EDD. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2010; 21:918-929. [PMID: 20363646 DOI: 10.1016/j.jasms.2010.02.025] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Revised: 02/18/2010] [Accepted: 02/18/2010] [Indexed: 05/29/2023]
Abstract
We have studied the effect of solution additives on hydrolysis and charge state distribution in ESI MS of RNA. Lower and higher charge state ions can be electrosprayed from solutions containing 25 mM piperidine/25 mM imidazole and 1% vol. triethylamine, respectively, with base-catalyzed hydrolysis rates that are sufficiently slow to perform MS/MS experiments. These lower and higher charge state ions are suitable as precursors for CAD and EDD, respectively. We demonstrate nearly complete sequence coverage for 61 nt RNA dissociated by CAD, and 34 nt RNA dissociated by EDD, and suggest a mechanism for backbone fragmentation in EDD of RNA.
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Affiliation(s)
- Monika Taucher
- Institute of Organic Chemistry and Center for Molecular Biosciences (CMBI), University of Innsbruck, Innsbruck, Austria
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28
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Fabris D. A role for the MS analysis of nucleic acids in the post-genomics age. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2010; 21:1-13. [PMID: 19897384 DOI: 10.1016/j.jasms.2009.09.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2009] [Revised: 09/04/2009] [Accepted: 09/04/2009] [Indexed: 05/28/2023]
Abstract
The advances of mass spectrometry in the analysis of nucleic acids have tracked very closely the exciting developments of instrumentation and ancillary technologies, which have taken place over the years. However, their diffusion in the broader life sciences community has been and will be linked to the ever evolving focus of biomedical research and its changing demands. Before the completion of the Human Genome Project, great emphasis was placed on sequencing technologies that could help accomplish this project of exceptional scale. After the publication of the human genome, the emphasis switched toward techniques dedicated to the exploration of sequences not coding for actual protein products, which amount to the vast majority of transcribed elements. The broad range of capabilities offered by mass spectrometry is rapidly advancing this platform to the forefront of the technologies employed for the structure-function investigation of these noncoding elements. Increasing focus on the characterization of functional assemblies and their specific interactions has prompted a re-evaluation of what has been traditionally construed as nucleic acid analysis by mass spectrometry. Inspired by the accelerating expansion of the broader field of nucleic acid research, new applications to fundamental biological studies and drug discovery will help redefine the evolving role of MS-analysis of nucleic acids in the post-genomics age.
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Affiliation(s)
- Daniele Fabris
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, Maryland 21228, USA.
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29
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Revisiting plus-strand DNA synthesis in retroviruses and long terminal repeat retrotransposons: dynamics of enzyme: substrate interactions. Viruses 2009; 1:657-77. [PMID: 21994564 PMCID: PMC3185511 DOI: 10.3390/v1030657] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Revised: 10/28/2009] [Accepted: 11/04/2009] [Indexed: 11/16/2022] Open
Abstract
Although polypurine tract (PPT)-primed initiation of plus-strand DNA synthesis in retroviruses and LTR-containing retrotransposons can be accurately duplicated, the molecular details underlying this concerted series of events remain largely unknown. Importantly, the PPT 3' terminus must be accommodated by ribonuclease H (RNase H) and DNA polymerase catalytic centers situated at either terminus of the cognate reverse transcriptase (RT), and in the case of the HIV-1 enzyme, ∼70Å apart. Communication between RT and the RNA/DNA hybrid therefore appears necessary to promote these events. The crystal structure of the HIV-1 RT/PPT complex, while informative, positions the RNase H active site several bases pairs from the PPT/U3 junction, and thus provides limited information on cleavage specificity. To fill the gap between biochemical and crystallographic approaches, we review a multidisciplinary approach combining chemical probing, mass spectrometry, NMR spectroscopy and single molecule spectroscopy. Our studies also indicate that nonnucleoside RT inhibitors affect enzyme orientation, suggesting initiation of plus-strand DNA synthesis as a potential therapeutic target.
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30
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Brinson RG, Turner KB, Yi-Brunozzi HY, Le Grice SFJ, Fabris D, Marino JP. Probing anomalous structural features in polypurine tract-containing RNA-DNA hybrids with neomycin B. Biochemistry 2009; 48:6988-97. [PMID: 19449839 DOI: 10.1021/bi900357j] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
During (-)-strand DNA synthesis in retroviruses and Saccharomyces cerevisiae LTR retrotransposons, a purine rich region of the RNA template, known as the polypurine tract (PPT), is resistant to RNase H-mediated hydrolysis and subsequently serves as a primer for (+)-strand, DNA-dependent DNA synthesis. Although HIV-1 and Ty3 PPT sequences share no sequence similarity beyond the fact that both include runs of purine ribonucleotides, it has been suggested that these PPTs are processed by their cognate reverse transcriptases (RTs) through a common molecular mechanism. Here, we have used the aminoglycoside neomycin B (NB) to examine which structural features of the Ty3 PPT contribute to specific recognition and processing by its cognate RT. Using high-resolution NMR, direct infusion FTICR mass spectrometry, and isothermal titration calorimetry, we show that NB binds preferentially and selectively adjacent to the Ty3 3' PPT-U3 cleavage junction and in an upstream 5' region where the thumb subdomain of Ty3 RT putatively grips the substrate. Regions highlighted by NB on the Ty3 PPT are similar to those previously identified on the HIV-1 PPT sequence that are implicated as contact points for substrate binding by its RT. Our findings thus support the notion that common structural features of lentiviral and LTR-retrotransposon PPTs facilitate the interaction with their cognate RT.
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Affiliation(s)
- Robert G Brinson
- Center for Advanced Research in Biotechnology of the University of Maryland Biotechnology Institute and the National Institute of Standards and Technology, 9600 Gudelsky Drive, Rockville, Maryland 20850, USA
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31
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Turner KB, Kohlway AS, Hagan NA, Fabris D. Noncovalent probes for the investigation of structure and dynamics of protein-nucleic acid assemblies: the case of NC-mediated dimerization of genomic RNA in HIV-1. Biopolymers 2009; 91:283-96. [PMID: 18946871 DOI: 10.1002/bip.21107] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The nature of specific RNA-RNA and protein-RNA interactions involved in the process of genome dimerization and isomerization in HIV-1, which is mediated in vitro by stemloop 1 (SL1) of the packaging signal and by the nucleocapsid (NC) domain of the viral Gag polyprotein, was investigated by using archetypical nucleic acid ligands as noncovalent probes. Small-molecule ligands make contact with their target substrates through complex combinations of H-bonds, salt bridges, and hydrophobic interactions. Therefore, their binding patterns assessed by electrospray ionization mass spectrometry can provide valuable insights into the factors determining specific recognition between species involved in biopolymer assemblies. In the case of SL1, dimerization and isomerization create unique structural features capable of sustaining stable interactions with classic nucleic acid ligands. The binding modes exhibited by intercalators and minor groove binders were adversely affected by the significant distortion of the duplex formed by palindrome annealing in the kissing-loop (KL) dimer, whereas the modes observed for the corresponding extended duplex (ED) confirmed a more regular helical structure. Consistent with the ability to establish electrostatic interactions with highly negative pockets typical of helix anomalies, polycationic aminoglycosides bound to the stem-bulge motif conserved in all SL1 conformers, to the unpaired nucleotides located at the hinge between kissing hairpins in KL, and to the exposed bases flanking the palindrome duplex in ED. The patterns afforded by intercalators and minor groove binders did not display detectable variations when the corresponding NC-SL1 complexes were submitted to probing. In contrast, aminoglycosides displayed the ability to compete with the protein for overlapping sites, producing opposite effects on the isomerization process. Indeed, displacing NC from the stem-bulges of the KL dimer induced inhibition of stem melting and decreased the efficiency of isomerization. Competition for the hinge region, instead, eliminated the NC stabilization of a grip motif formed by nucleobases of opposite strands, thus facilitating the strand-exchange required for isomerization. These noncovalent probes provided further evidence that the structural context of the actual binding sites has significant influence on the chaperone activities of NC, which should be taken in account when developing potential drug candidates aimed at disrupting genome dimerization and isomerization in HIV-1.
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Affiliation(s)
- Kevin B Turner
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD, USA
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32
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Rosu F, De Pauw E, Gabelica V. Electrospray mass spectrometry to study drug-nucleic acids interactions. Biochimie 2008; 90:1074-87. [DOI: 10.1016/j.biochi.2008.01.005] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Accepted: 01/11/2008] [Indexed: 12/27/2022]
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33
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Turner KB, Brinson RG, Yi-Brunozzi HY, Rausch JW, Miller JT, Le Grice SFJ, Marino JP, Fabris D. Structural probing of the HIV-1 polypurine tract RNA:DNA hybrid using classic nucleic acid ligands. Nucleic Acids Res 2008; 36:2799-810. [PMID: 18400780 PMCID: PMC2377446 DOI: 10.1093/nar/gkn129] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The interactions of archetypical nucleic acid ligands with the HIV-1 polypurine tract (PPT) RNA:DNA hybrid, as well as analogous DNA:DNA, RNA:RNA and swapped hybrid substrates, were used to probe structural features of the PPT that contribute to its specific recognition and processing by reverse transcriptase (RT). Results from intercalative and groove-binding ligands indicate that the wild-type PPT hybrid does not contain any strikingly unique groove geometries and/or stacking arrangements that might contribute to the specificity of its interaction with RT. In contrast, neomycin bound preferentially and selectively to the PPT near the 5′(rA)4:(dT)4 tract and the 3′ PPT-U3 junction. Nuclear magnetic resonance data from a complex between HIV-1 RT and the PPT indicate RT contacts within the same regions highlighted on the PPT by neomycin. These observations, together with the fact that the sites are correctly spaced to allow interaction with residues in the ribonuclease H (RNase H) active site and thumb subdomain of the p66 RT subunit, suggest that despite the long cleft employed by RT to make contact with nucleic acids substrates, these sites provide discrete binding units working in concert to determine not only specific PPT recognition, but also its orientation on the hybrid structure.
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Affiliation(s)
- Kevin B Turner
- University of Maryland Baltimore County, Baltimore, MD, USA
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34
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Turner KB, Hagan NA, Fabris D. Understanding the isomerization of the HIV-1 dimerization initiation domain by the nucleocapsid protein. J Mol Biol 2007; 369:812-28. [PMID: 17466332 PMCID: PMC2475603 DOI: 10.1016/j.jmb.2007.03.065] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2007] [Revised: 03/20/2007] [Accepted: 03/23/2007] [Indexed: 10/23/2022]
Abstract
The specific binding of HIV-1 nucleocapsid (NC) to the hinge region of the kissing-loop (KL) dimer formed by stemloop 1 (SL1) can have significant consequences on its ability to isomerize into the corresponding extended duplex (ED) form. The binding determinants and the effects on the isomerization process were investigated in vitro by a concerted strategy involving ad hoc RNA mutants and electrospray ionization-Fourier transform ion cyclotron resonance (ESI-FTICR) mass spectrometry, which enabled us to characterize the stoichiometry and conformational state of all possible protein-RNA and RNA-RNA assemblies present simultaneously in solution. For the first time, NC-hinge interactions were observed in constructs including at least one unpaired guanine at the 5'-end of the loop-loop duplex, whereas no interactions were detected when the unpaired guanine was placed at its 3'-end. This binding mode is supported by the presence of a grip-like motif described by recent crystal structures, which is formed by the 5'-purines of both hairpins held together by mutual stacking interactions. Using tandem mass spectrometry, hinge interactions were clearly shown to reduce the efficiency of KL/ED isomerization without inducing its complete block. This outcome is consistent with the partial stabilization of the extra-helical grip by the bound protein, which can hamper the purine components from parting ways and initiate the strand exchange process. These findings confirm that the broad binding and chaperone activities of NC induce unique effects that are clearly dependent on the structural context of the cognate nucleic acid substrate. For this reason, the presence of multiple binding sites on the different forms assumed by SL1 can produce seemingly contrasting effects that contribute to a fine modulation of the two-step process of RNA dimerization and isomerization.
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Affiliation(s)
- Kevin B. Turner
- University of Maryland Baltimore County, Department of Chemistry and Biochemistry, 1000 Hilltop Circle, Baltimore, MD 21228 USA, Tel. (410) 455-3053, Fax. (410) 455-2608,
| | - Nathan A. Hagan
- University of Maryland Baltimore County, Department of Chemistry and Biochemistry, 1000 Hilltop Circle, Baltimore, MD 21228 USA, Tel. (410) 455-3053, Fax. (410) 455-2608,
| | - Daniele Fabris
- University of Maryland Baltimore County, Department of Chemistry and Biochemistry, 1000 Hilltop Circle, Baltimore, MD 21228 USA, Tel. (410) 455-3053, Fax. (410) 455-2608,
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