1
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Botova M, Camacho-Zarco AR, Tognetti J, Bessa LM, Guseva S, Mikkola E, Salvi N, Maurin D, Herrmann T, Blackledge M. A specific phosphorylation-dependent conformational switch in SARS-CoV-2 nucleocapsid protein inhibits RNA binding. SCIENCE ADVANCES 2024; 10:eaax2323. [PMID: 39093972 PMCID: PMC11296341 DOI: 10.1126/sciadv.aax2323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 06/27/2024] [Indexed: 08/04/2024]
Abstract
The nucleocapsid protein of severe acute respiratory syndrome coronavirus 2 encapsidates the viral genome and is essential for viral function. The central disordered domain comprises a serine-arginine-rich (SR) region that is hyperphosphorylated in infected cells. This modification regulates function, although mechanistic details remain unknown. We use nuclear magnetic resonance to follow structural changes occurring during hyperphosphorylation by serine arginine protein kinase 1, glycogen synthase kinase 3, and casein kinase 1, that abolishes interaction with RNA. When eight approximately uniformly distributed sites have been phosphorylated, the SR domain binds the same interface as single-stranded RNA, resulting in complete inhibition of RNA binding. Phosphorylation by protein kinase A does not prevent RNA binding, indicating that the pattern resulting from physiologically relevant kinases is specific for inhibition. Long-range contacts between the RNA binding, linker, and dimerization domains are abrogated, phenomena possibly related to genome packaging and unpackaging. This study provides insight into the recruitment of specific host kinases to regulate viral function.
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Affiliation(s)
| | | | | | | | | | - Emmi Mikkola
- Université Grenoble Alpes, CNRS, CEA, IBS, F-38000 Grenoble, France
| | | | - Damien Maurin
- Université Grenoble Alpes, CNRS, CEA, IBS, F-38000 Grenoble, France
| | - Torsten Herrmann
- Université Grenoble Alpes, CNRS, CEA, IBS, F-38000 Grenoble, France
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2
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Toews S, Wacker A, Faison EM, Duchardt-Ferner E, Richter C, Mathieu D, Bottaro S, Zhang Q, Schwalbe H. The 5'-terminal stem-loop RNA element of SARS-CoV-2 features highly dynamic structural elements that are sensitive to differences in cellular pH. Nucleic Acids Res 2024; 52:7971-7986. [PMID: 38842942 PMCID: PMC11260494 DOI: 10.1093/nar/gkae477] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 05/16/2024] [Accepted: 05/22/2024] [Indexed: 07/23/2024] Open
Abstract
We present the nuclear magnetic resonance spectroscopy (NMR) solution structure of the 5'-terminal stem loop 5_SL1 (SL1) of the SARS-CoV-2 genome. SL1 contains two A-form helical elements and two regions with non-canonical structure, namely an apical pyrimidine-rich loop and an asymmetric internal loop with one and two nucleotides at the 5'- and 3'-terminal part of the sequence, respectively. The conformational ensemble representing the averaged solution structure of SL1 was validated using NMR residual dipolar coupling (RDC) and small-angle X-ray scattering (SAXS) data. We show that the internal loop is the major binding site for fragments of low molecular weight. This internal loop of SL1 can be stabilized by an A12-C28 interaction that promotes the transient formation of an A+•C base pair. As a consequence, the pKa of the internal loop adenosine A12 is shifted to 5.8, compared to a pKa of 3.63 of free adenosine. Furthermore, applying a recently developed pH-differential mutational profiling (PD-MaP) approach, we not only recapitulated our NMR findings of SL1 but also unveiled multiple sites potentially sensitive to pH across the 5'-UTR of SARS-CoV-2.
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Affiliation(s)
- Sabrina Toews
- Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University Frankfurt, Frankfurt/Main, Hesse 60438, Germany
- Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University Frankfurt, Frankfurt/Main, Hesse 60438, Germany
| | - Anna Wacker
- Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University Frankfurt, Frankfurt/Main, Hesse 60438, Germany
- Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University Frankfurt, Frankfurt/Main, Hesse 60438, Germany
| | - Edgar M Faison
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC27599, USA
| | - Elke Duchardt-Ferner
- Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University Frankfurt, Frankfurt/Main, Hesse 60438, Germany
- Institute of Molecular Biosciences, Johann Wolfgang Goethe-University Frankfurt, Frankfurt/Main, Hesse 60438, Germany
| | - Christian Richter
- Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University Frankfurt, Frankfurt/Main, Hesse 60438, Germany
- Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University Frankfurt, Frankfurt/Main, Hesse 60438, Germany
| | - Daniel Mathieu
- Bruker BioSpin GmbH, Ettlingen, Baden-Württemberg 76275, Germany
| | - Sandro Bottaro
- Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen 2200, Denmark
| | - Qi Zhang
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC27599, USA
| | - Harald Schwalbe
- Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University Frankfurt, Frankfurt/Main, Hesse 60438, Germany
- Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University Frankfurt, Frankfurt/Main, Hesse 60438, Germany
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3
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von Ehr J, Oberstrass L, Yazgan E, Schnaubelt LI, Blümel N, McNicoll F, Weigand JE, Zarnack K, Müller-McNicoll M, Korn SM, Schlundt A. Arid5a uses disordered extensions of its core ARID domain for distinct DNA- and RNA-recognition and gene regulation. J Biol Chem 2024; 300:107457. [PMID: 38866324 PMCID: PMC11262183 DOI: 10.1016/j.jbc.2024.107457] [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: 04/10/2024] [Revised: 05/23/2024] [Accepted: 06/01/2024] [Indexed: 06/14/2024] Open
Abstract
AT-rich interacting domain (ARID)-containing proteins, Arids, are a heterogeneous DNA-binding protein family involved in transcription regulation and chromatin processing. For the member Arid5a, no exact DNA-binding preference has been experimentally defined so far. Additionally, the protein binds to mRNA motifs for transcript stabilization, supposedly through the DNA-binding ARID domain. To date, however, no unbiased RNA motif definition and clear dissection of nucleic acid-binding through the ARID domain have been undertaken. Using NMR-centered biochemistry, we here define the Arid5a DNA preference. Further, high-throughput in vitro binding reveals a consensus RNA-binding motif engaged by the core ARID domain. Finally, transcriptome-wide binding (iCLIP2) reveals that Arid5a has a weak preference for (A)U-rich regions in pre-mRNA transcripts of factors related to RNA processing. We find that the intrinsically disordered regions flanking the ARID domain modulate the specificity and affinity of DNA binding, while they appear crucial for RNA interactions. Ultimately, our data suggest that Arid5a uses its extended ARID domain for bifunctional gene regulation and that the involvement of IDR extensions is a more general feature of Arids in interacting with different nucleic acids at the chromatin-mRNA interface.
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Affiliation(s)
- Julian von Ehr
- Institute for Molecular Biosciences and Biomolecular Resonance Center (BMRZ), Goethe University Frankfurt, Frankfurt, Germany; IMPRS on Cellular Biophysics, Frankfurt, Germany
| | - Lasse Oberstrass
- University of Marburg, Department of Pharmacy, Institute of Pharmaceutical Chemistry, Marburg, Germany
| | - Ege Yazgan
- Institute for Molecular Biosciences, Goethe University Frankfurt, Frankfurt, Germany; Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
| | - Lara Ina Schnaubelt
- Institute for Molecular Biosciences and Biomolecular Resonance Center (BMRZ), Goethe University Frankfurt, Frankfurt, Germany
| | - Nicole Blümel
- Institute for Molecular Biosciences, Goethe University Frankfurt, Frankfurt, Germany
| | - Francois McNicoll
- Institute for Molecular Biosciences, Goethe University Frankfurt, Frankfurt, Germany
| | - Julia E Weigand
- University of Marburg, Department of Pharmacy, Institute of Pharmaceutical Chemistry, Marburg, Germany
| | - Kathi Zarnack
- Institute for Molecular Biosciences, Goethe University Frankfurt, Frankfurt, Germany; Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
| | - Michaela Müller-McNicoll
- Institute for Molecular Biosciences, Goethe University Frankfurt, Frankfurt, Germany; Max-Planck Institute for Biophysics, Frankfurt, Germany
| | - Sophie Marianne Korn
- Institute for Molecular Biosciences and Biomolecular Resonance Center (BMRZ), Goethe University Frankfurt, Frankfurt, Germany; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York, USA.
| | - Andreas Schlundt
- Institute for Molecular Biosciences and Biomolecular Resonance Center (BMRZ), Goethe University Frankfurt, Frankfurt, Germany; University of Greifswald, Institute of Biochemistry, Greifswald, Germany.
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4
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Zhao H, Syed AM, Khalid MM, Nguyen A, Ciling A, Wu D, Yau WM, Srinivasan S, Esposito D, Doudna J, Piszczek G, Ott M, Schuck P. Assembly of SARS-CoV-2 nucleocapsid protein with nucleic acid. Nucleic Acids Res 2024; 52:6647-6661. [PMID: 38587193 PMCID: PMC11194069 DOI: 10.1093/nar/gkae256] [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: 11/22/2023] [Revised: 03/18/2024] [Accepted: 03/27/2024] [Indexed: 04/09/2024] Open
Abstract
The viral genome of SARS-CoV-2 is packaged by the nucleocapsid (N-)protein into ribonucleoprotein particles (RNPs), 38 ± 10 of which are contained in each virion. Their architecture has remained unclear due to the pleomorphism of RNPs, the high flexibility of N-protein intrinsically disordered regions, and highly multivalent interactions between viral RNA and N-protein binding sites in both N-terminal (NTD) and C-terminal domain (CTD). Here we explore critical interaction motifs of RNPs by applying a combination of biophysical techniques to ancestral and mutant proteins binding different nucleic acids in an in vitro assay for RNP formation, and by examining nucleocapsid protein variants in a viral assembly assay. We find that nucleic acid-bound N-protein dimers oligomerize via a recently described protein-protein interface presented by a transient helix in its long disordered linker region between NTD and CTD. The resulting hexameric complexes are stabilized by multivalent protein-nucleic acid interactions that establish crosslinks between dimeric subunits. Assemblies are stabilized by the dimeric CTD of N-protein offering more than one binding site for stem-loop RNA. Our study suggests a model for RNP assembly where N-protein scaffolding at high density on viral RNA is followed by cooperative multimerization through protein-protein interactions in the disordered linker.
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Affiliation(s)
- Huaying Zhao
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
| | - Abdullah M Syed
- Gladstone Institutes, San Francisco, CA 94158, USA
- Innovative Genomics Institute, University of California, Berkeley, CA 94720, USA
| | - Mir M Khalid
- Gladstone Institutes, San Francisco, CA 94158, USA
| | - Ai Nguyen
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
| | - Alison Ciling
- Gladstone Institutes, San Francisco, CA 94158, USA
- Innovative Genomics Institute, University of California, Berkeley, CA 94720, USA
| | - Di Wu
- Biophysics Core Facility, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Wai-Ming Yau
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sanjana Srinivasan
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
| | - Dominic Esposito
- Protein Expression Laboratory, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Jennifer A Doudna
- Gladstone Institutes, San Francisco, CA 94158, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
- HHMI, University of California, Berkeley, CA 94720, USA
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA 94720, USA
| | - Grzegorz Piszczek
- Biophysics Core Facility, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Melanie Ott
- Gladstone Institutes, San Francisco, CA 94158, USA
- Department of Medicine, University of California, San Francisco, CA 94143, USA
- Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
| | - Peter Schuck
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
- Center for Biomedical Engineering Technology Acceleration, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
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5
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Chen Y, Sun S, Liu X, Li H, Huan S, Xiong B, Zhang XB. Plasmonic Imaging of Multivalent NTD-Nucleic Acid Interactions for Broad-Spectrum Antiviral Drug Analysis. Anal Chem 2024; 96:9551-9560. [PMID: 38787915 DOI: 10.1021/acs.analchem.4c01037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2024]
Abstract
The discovery and identification of broad-spectrum antiviral drugs are of great significance for blocking the spread of pathogenic viruses and corresponding variants of concern. Herein, we proposed a plasmonic imaging-based strategy for assessing the efficacy of potential broad-spectrum antiviral drugs targeting the N-terminal domain of a nucleocapsid protein (NTD) and nucleic acid (NA) interactions. With NTD and NA conjugated gold nanoparticles as core and satellite nanoprobes, respectively, we found that the multivalent binding interactions could drive the formation of core-satellite nanostructures with enhanced scattering brightness due to the plasmonic coupling effect. The core-satellite assembly can be suppressed in the presence of antiviral drugs targeting the NTD-NA interactions, allowing the drug efficacy analysis by detecting the dose-dependent changes in the scattering brightness by plasmonic imaging. By quantifying the changes in the scattering brightness of plasmonic nanoprobes, we uncovered that the constructed multivalent weak interactions displayed a 500-fold enhancement in affinity as compared with the monovalent NTD-NA interactions. We demonstrated the plasmonic imaging-based strategy for evaluating the efficacy of a potential broad-spectrum drug, PJ34, that can target the NTD-NA interactions, with the IC50 as 24.35 and 14.64 μM for SARS-CoV-2 and SARS-CoV, respectively. Moreover, we discovered that ceftazidime holds the potential as a candidate drug to inhibit the NTD-NA interactions with an IC50 of 22.08 μM from molecular docking and plasmonic imaging-based drug analysis. Finally, we validated that the potential antiviral drug, 5-benzyloxygramine, which can induce the abnormal dimerization of nucleocapsid proteins, is effective for SARS-CoV-2, but not effective against SARS-CoV. All these demonstrations indicated that the plasmonic imaging-based strategy is robust and can be used as a powerful strategy for the discovery and identification of broad-spectrum drugs targeting the evolutionarily conserved viral proteins.
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Affiliation(s)
- Yancao Chen
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Shijie Sun
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Xixuan Liu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Huiwen Li
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Shuangyan Huan
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Bin Xiong
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Xiao-Bing Zhang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
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6
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Stuwe H, Reardon PN, Yu Z, Shah S, Hughes K, Barbar EJ. Phosphorylation in the Ser/Arg-rich region of the nucleocapsid of SARS-CoV-2 regulates phase separation by inhibiting self-association of a distant helix. J Biol Chem 2024; 300:107354. [PMID: 38718862 PMCID: PMC11180338 DOI: 10.1016/j.jbc.2024.107354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 04/24/2024] [Accepted: 04/30/2024] [Indexed: 06/06/2024] Open
Abstract
The nucleocapsid protein (N) of SARS-CoV-2 is essential for virus replication, genome packaging, evading host immunity, and virus maturation. N is a multidomain protein composed of an independently folded monomeric N-terminal domain that is the primary site for RNA binding and a dimeric C-terminal domain that is essential for efficient phase separation and condensate formation with RNA. The domains are separated by a disordered Ser/Arg-rich region preceding a self-associating Leu-rich helix. Phosphorylation in the Ser/Arg region in infected cells decreases the viscosity of N:RNA condensates promoting viral replication and host immune evasion. The molecular level effect of phosphorylation, however, is missing from our current understanding. Using NMR spectroscopy and analytical ultracentrifugation, we show that phosphorylation destabilizes the self-associating Leu-rich helix 30 amino-acids distant from the phosphorylation site. NMR and gel shift assays demonstrate that RNA binding by the linker is dampened by phosphorylation, whereas RNA binding to the full-length protein is not significantly affected presumably due to retained strong interactions with the primary RNA-binding domain. Introducing a switchable self-associating domain to replace the Leu-rich helix confirms the importance of linker self-association to droplet formation and suggests that phosphorylation not only increases solubility of the positively charged elongated Ser/Arg region as observed in other RNA-binding proteins but can also inhibit self-association of the Leu-rich helix. These data highlight the effect of phosphorylation both at local sites and at a distant self-associating hydrophobic helix in regulating liquid-liquid phase separation of the entire protein.
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Affiliation(s)
- Hannah Stuwe
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon, USA
| | | | - Zhen Yu
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon, USA
| | - Sahana Shah
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon, USA
| | - Kaitlyn Hughes
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon, USA
| | - Elisar J Barbar
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon, USA.
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7
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Yin Y, Yang Z, Sun Y, Yang Y, Zhang X, Zhao X, Tian W, Qiu Y, Yin Y, You F, Lu D. RNA-binding protein PTENα blocks RIG-I activation to prevent viral inflammation. Nat Chem Biol 2024:10.1038/s41589-024-01621-5. [PMID: 38773328 DOI: 10.1038/s41589-024-01621-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 04/15/2024] [Indexed: 05/23/2024]
Abstract
A timely inflammatory response is crucial for early viral defense, but uncontrolled inflammation harms the host. Retinoic acid-inducible gene I (RIG-I) has a pivotal role in detecting RNA viruses, yet the regulatory mechanisms governing its sensitivity remain elusive. Here we identify PTENα, an N-terminally extended form of PTEN, as an RNA-binding protein with a preference for the CAUC(G/U)UCAU motif. Using both in vivo and in vitro viral infection assays, we demonstrated that PTENα restricted the host innate immune response, relying on its RNA-binding capacity and phosphatase activity. Mechanistically, PTENα directly bound to viral RNA and enzymatically converted its 5'-triphosphate to 5'-monophosphate, thereby reducing RIG-I sensitivity. Physiologically, brain-intrinsic PTENα exerted protective effects against viral inflammation, while peripheral PTENα restricted host antiviral immunity and, to some extent, promoted viral replication. Collectively, our findings underscore the significance of PTENα in modulating viral RNA- and RIG-I-mediated immune recognition, offering potential therapeutic implications for infectious diseases.
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Affiliation(s)
- Yue Yin
- Institute of Systems Biomedicine, Department of Immunology, Department of Pathology, School of Basic Medical Sciences, NHC Key Laboratory of Medical Immunology, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, P.R. China
| | - Zeliang Yang
- Institute of Systems Biomedicine, Department of Immunology, Department of Pathology, School of Basic Medical Sciences, NHC Key Laboratory of Medical Immunology, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, P.R. China
| | - Yizhe Sun
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Ying Yang
- Department of Blood Transfusion, Peking University People's Hospital, Beijing, P.R. China
| | - Xin Zhang
- Institute of Systems Biomedicine, Department of Immunology, Department of Pathology, School of Basic Medical Sciences, NHC Key Laboratory of Medical Immunology, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, P.R. China
| | - Xuyang Zhao
- Institute of Systems Biomedicine, Department of Immunology, Department of Pathology, School of Basic Medical Sciences, NHC Key Laboratory of Medical Immunology, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, P.R. China
| | - Wenyu Tian
- Institute of Systems Biomedicine, Department of Immunology, Department of Pathology, School of Basic Medical Sciences, NHC Key Laboratory of Medical Immunology, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, P.R. China
| | - Yaruo Qiu
- Institute of Systems Biomedicine, Department of Immunology, Department of Pathology, School of Basic Medical Sciences, NHC Key Laboratory of Medical Immunology, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, P.R. China
| | - Yuxin Yin
- Institute of Systems Biomedicine, Department of Immunology, Department of Pathology, School of Basic Medical Sciences, NHC Key Laboratory of Medical Immunology, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, P.R. China.
| | - Fuping You
- Institute of Systems Biomedicine, Department of Immunology, Department of Pathology, School of Basic Medical Sciences, NHC Key Laboratory of Medical Immunology, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, P.R. China.
| | - Dan Lu
- Institute of Systems Biomedicine, Department of Immunology, Department of Pathology, School of Basic Medical Sciences, NHC Key Laboratory of Medical Immunology, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, P.R. China.
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8
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Kathe NC, Novakovic M, Allain FHT. Buffer choice and pH strongly influence phase separation of SARS-CoV-2 nucleocapsid with RNA. Mol Biol Cell 2024; 35:ar73. [PMID: 38568799 PMCID: PMC11151101 DOI: 10.1091/mbc.e23-12-0500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 03/18/2024] [Accepted: 03/25/2024] [Indexed: 04/05/2024] Open
Abstract
The SARS-CoV-2 nucleocapsid (N) protein is crucial for virus replication and genome packaging. N protein forms biomolecular condensates both in vitro and in vivo in a process known as liquid-liquid phase separation (LLPS), but the exact factors regulating LLPS of N protein are not fully understood. Here, we show that pH and buffer choice have a profound impact on LLPS of N protein. The degree of phase separation is highly dependent on the pH of the solution, which is correlated with histidine protonation in N protein. Specifically, we demonstrate that protonation of H356 is essential for LLPS in phosphate buffer. Moreover, electrostatic interactions of buffer molecules with specific amino acid residues are able to alter the net charge of N protein, thus influencing its ability to undergo phase separation in the presence of RNA. Overall, these findings reveal that even subtle changes in amino acid protonation or surface charge caused by the pH and buffer system can strongly influence the LLPS behavior, and point to electrostatic interactions as the main driving forces of N protein phase separation. Further, our findings emphasize the importance of these experimental parameters when studying phase separation of biomolecules, especially in the context of viral infections where the intracellular milieu undergoes drastic changes and intracellular pH normally decreases.
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Affiliation(s)
- Nina C. Kathe
- Department of Biology, Institute of Biochemistry, ETH Zurich, Zurich, Switzerland
| | - Mihajlo Novakovic
- Department of Biology, Institute of Biochemistry, ETH Zurich, Zurich, Switzerland
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9
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de Moura TR, Purta E, Bernat A, Martín-Cuevas E, Kurkowska M, Baulin E, Mukherjee S, Nowak J, Biela A, Rawski M, Glatt S, Moreno-Herrero F, Bujnicki J. Conserved structures and dynamics in 5'-proximal regions of Betacoronavirus RNA genomes. Nucleic Acids Res 2024; 52:3419-3432. [PMID: 38426934 PMCID: PMC11014237 DOI: 10.1093/nar/gkae144] [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: 10/09/2023] [Revised: 01/25/2024] [Accepted: 02/26/2024] [Indexed: 03/02/2024] Open
Abstract
Betacoronaviruses are a genus within the Coronaviridae family of RNA viruses. They are capable of infecting vertebrates and causing epidemics as well as global pandemics in humans. Mitigating the threat posed by Betacoronaviruses requires an understanding of their molecular diversity. The development of novel antivirals hinges on understanding the key regulatory elements within the viral RNA genomes, in particular the 5'-proximal region, which is pivotal for viral protein synthesis. Using a combination of cryo-electron microscopy, atomic force microscopy, chemical probing, and computational modeling, we determined the structures of 5'-proximal regions in RNA genomes of Betacoronaviruses from four subgenera: OC43-CoV, SARS-CoV-2, MERS-CoV, and Rousettus bat-CoV. We obtained cryo-electron microscopy maps and determined atomic-resolution models for the stem-loop-5 (SL5) region at the translation start site and found that despite low sequence similarity and variable length of the helical elements it exhibits a remarkable structural conservation. Atomic force microscopy imaging revealed a common domain organization and a dynamic arrangement of structural elements connected with flexible linkers across all four Betacoronavirus subgenera. Together, these results reveal common features of a critical regulatory region shared between different Betacoronavirus RNA genomes, which may allow targeting of these RNAs by broad-spectrum antiviral therapeutics.
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Affiliation(s)
- Tales Rocha de Moura
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology in Warsaw, ul. Ks. Trojdena 4, 02-109 Warsaw, Poland
| | - Elżbieta Purta
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology in Warsaw, ul. Ks. Trojdena 4, 02-109 Warsaw, Poland
| | - Agata Bernat
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology in Warsaw, ul. Ks. Trojdena 4, 02-109 Warsaw, Poland
| | - Eva M Martín-Cuevas
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Małgorzata Kurkowska
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology in Warsaw, ul. Ks. Trojdena 4, 02-109 Warsaw, Poland
| | - Eugene F Baulin
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology in Warsaw, ul. Ks. Trojdena 4, 02-109 Warsaw, Poland
| | - Sunandan Mukherjee
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology in Warsaw, ul. Ks. Trojdena 4, 02-109 Warsaw, Poland
| | - Jakub Nowak
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
| | - Artur P Biela
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
| | - Michał Rawski
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
- National Synchrotron Radiation Centre SOLARIS, Jagiellonian University, Krakow, Poland
| | - Sebastian Glatt
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
| | - Fernando Moreno-Herrero
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Janusz M Bujnicki
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology in Warsaw, ul. Ks. Trojdena 4, 02-109 Warsaw, Poland
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10
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Cubuk J, Alston J, Incicco JJ, Holehouse A, Hall K, Stuchell-Brereton M, Soranno A. The disordered N-terminal tail of SARS-CoV-2 Nucleocapsid protein forms a dynamic complex with RNA. Nucleic Acids Res 2024; 52:2609-2624. [PMID: 38153183 PMCID: PMC10954482 DOI: 10.1093/nar/gkad1215] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 11/17/2023] [Accepted: 12/11/2023] [Indexed: 12/29/2023] Open
Abstract
The SARS-CoV-2 Nucleocapsid (N) protein is responsible for condensation of the viral genome. Characterizing the mechanisms controlling nucleic acid binding is a key step in understanding how condensation is realized. Here, we focus on the role of the RNA binding domain (RBD) and its flanking disordered N-terminal domain (NTD) tail, using single-molecule Förster Resonance Energy Transfer and coarse-grained simulations. We quantified contact site size and binding affinity for nucleic acids and concomitant conformational changes occurring in the disordered region. We found that the disordered NTD increases the affinity of the RBD for RNA by about 50-fold. Binding of both nonspecific and specific RNA results in a modulation of the tail configurations, which respond in an RNA length-dependent manner. Not only does the disordered NTD increase affinity for RNA, but mutations that occur in the Omicron variant modulate the interactions, indicating a functional role of the disordered tail. Finally, we found that the NTD-RBD preferentially interacts with single-stranded RNA and that the resulting protein:RNA complexes are flexible and dynamic. We speculate that this mechanism of interaction enables the Nucleocapsid protein to search the viral genome for and bind to high-affinity motifs.
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Affiliation(s)
- Jasmine Cubuk
- Department of Biochemistry and Molecular Biophysics, Washington University in St Louis, 660 St Euclid Ave, 63110 Saint Louis, MO, USA
- Center for Biomolecular Condensates, Washington University in St Louis, 1 Brookings Drive, 63130 Saint Louis, MO, USA
| | - Jhullian J Alston
- Department of Biochemistry and Molecular Biophysics, Washington University in St Louis, 660 St Euclid Ave, 63110 Saint Louis, MO, USA
- Center for Biomolecular Condensates, Washington University in St Louis, 1 Brookings Drive, 63130 Saint Louis, MO, USA
| | - J Jeremías Incicco
- Department of Biochemistry and Molecular Biophysics, Washington University in St Louis, 660 St Euclid Ave, 63110 Saint Louis, MO, USA
- Center for Biomolecular Condensates, Washington University in St Louis, 1 Brookings Drive, 63130 Saint Louis, MO, USA
| | - Alex S Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University in St Louis, 660 St Euclid Ave, 63110 Saint Louis, MO, USA
- Center for Biomolecular Condensates, Washington University in St Louis, 1 Brookings Drive, 63130 Saint Louis, MO, USA
| | - Kathleen B Hall
- Department of Biochemistry and Molecular Biophysics, Washington University in St Louis, 660 St Euclid Ave, 63110 Saint Louis, MO, USA
| | - Melissa D Stuchell-Brereton
- Department of Biochemistry and Molecular Biophysics, Washington University in St Louis, 660 St Euclid Ave, 63110 Saint Louis, MO, USA
- Center for Biomolecular Condensates, Washington University in St Louis, 1 Brookings Drive, 63130 Saint Louis, MO, USA
| | - Andrea Soranno
- Department of Biochemistry and Molecular Biophysics, Washington University in St Louis, 660 St Euclid Ave, 63110 Saint Louis, MO, USA
- Center for Biomolecular Condensates, Washington University in St Louis, 1 Brookings Drive, 63130 Saint Louis, MO, USA
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11
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Chamberlain SR, Moore S, Grant TD. Fitting high-resolution electron density maps from atomic models to solution scattering data. Biophys J 2023; 122:4567-4581. [PMID: 37924208 PMCID: PMC10719074 DOI: 10.1016/j.bpj.2023.10.034] [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: 06/05/2023] [Revised: 08/29/2023] [Accepted: 10/31/2023] [Indexed: 11/06/2023] Open
Abstract
Solution scattering techniques, such as small- and wide-angle X-ray scattering (SWAXS), provide valuable insights into the structure and dynamics of biological macromolecules in solution. In this study, we present an approach to accurately predict solution X-ray scattering profiles at wide angles from atomic models by generating high-resolution electron density maps. Our method accounts for the excluded volume of bulk solvent by calculating unique adjusted atomic volumes directly from the atomic coordinates. This approach eliminates the need for one of the free fitting parameters commonly used in existing algorithms, resulting in improved accuracy of the calculated SWAXS profile. An implicit model of the hydration shell is generated that uses the form factor of water. Two parameters, namely the bulk solvent density and the mean hydration shell contrast, are adjusted to best fit the data. Results using eight publicly available SWAXS profiles show high-quality fits to the data. In each case, the optimized parameter values show small adjustments demonstrating that the default values are close to the true solution. Disabling parameter optimization produces significantly more accurate predicted scattering profiles compared to the leading software. The algorithm is computationally efficient, comparable to the leading software and up to 10 times faster for large molecules. The algorithm is encoded in a command line script called denss.pdb2mrc.py and is available open source as part of the DENSS v1.7.0 software package. In addition to improving the ability to compare atomic models to experimental SWAXS data, these developments pave the way for increasing the accuracy of modeling algorithms using SWAXS data and decreasing the risk of overfitting.
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Affiliation(s)
- Sarah R Chamberlain
- Department of Structural Biology, Jacobs School of Medicine and Biomedical Sciences, SUNY University at Buffalo, Buffalo, New York
| | - Stephen Moore
- Department of Structural Biology, Jacobs School of Medicine and Biomedical Sciences, SUNY University at Buffalo, Buffalo, New York
| | - Thomas D Grant
- Department of Structural Biology, Jacobs School of Medicine and Biomedical Sciences, SUNY University at Buffalo, Buffalo, New York.
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12
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Zhao H, Syed AM, Khalid MM, Nguyen A, Ciling A, Wu D, Yau WM, Srinivasan S, Esposito D, Doudna JA, Piszczek G, Ott M, Schuck P. Assembly reactions of SARS-CoV-2 nucleocapsid protein with nucleic acid. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.22.568361. [PMID: 38045338 PMCID: PMC10690241 DOI: 10.1101/2023.11.22.568361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
The viral genome of SARS-CoV-2 is packaged by the nucleocapsid (N-) protein into ribonucleoprotein particles (RNPs), 38±10 of which are contained in each virion. Their architecture has remained unclear due to the pleomorphism of RNPs, the high flexibility of N-protein intrinsically disordered regions, and highly multivalent interactions between viral RNA and N-protein binding sites in both N-terminal (NTD) and C-terminal domain (CTD). Here we explore critical interaction motifs of RNPs by applying a combination of biophysical techniques to mutant proteins binding different nucleic acids in an in vitro assay for RNP formation, and by examining mutant proteins in a viral assembly assay. We find that nucleic acid-bound N-protein dimers oligomerize via a recently described protein-protein interface presented by a transient helix in its long disordered linker region between NTD and CTD. The resulting hexameric complexes are stabilized by multi-valent protein-nucleic acid interactions that establish crosslinks between dimeric subunits. Assemblies are stabilized by the dimeric CTD of N-protein offering more than one binding site for stem-loop RNA. Our study suggests a model for RNP assembly where N-protein scaffolding at high density on viral RNA is followed by cooperative multimerization through protein-protein interactions in the disordered linker.
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Affiliation(s)
- Huaying Zhao
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892
| | - Abdullah M. Syed
- Gladstone Institutes, San Francisco, CA 94158
- Innovative Genomics Institute, University of California, Berkeley, CA 94720
| | | | - Ai Nguyen
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892
| | - Alison Ciling
- Gladstone Institutes, San Francisco, CA 94158
- Innovative Genomics Institute, University of California, Berkeley, CA 94720
| | - Di Wu
- Biophysics Core Facility, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Wai-Ming Yau
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Sanjana Srinivasan
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892
| | - Dominic Esposito
- Protein Expression Laboratory, Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Jennifer A. Doudna
- Gladstone Institutes, San Francisco, CA 94158
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
- HHMI, University of California, Berkeley, CA 94720
- Department of Chemistry, University of California, Berkeley, CA 94720
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA 94720
| | - Grzegorz Piszczek
- Biophysics Core Facility, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Melanie Ott
- Gladstone Institutes, San Francisco, CA 94158
- Department of Medicine, University of California, San Francisco, CA 94143
- Chan Zuckerberg Biohub, San Francisco, CA 94158
| | - Peter Schuck
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892
- Center for Biomedical Engineering Technology Acceleration, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892
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13
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Estelle AB, Forsythe HM, Yu Z, Hughes K, Lasher B, Allen P, Reardon PN, Hendrix DA, Barbar EJ. RNA structure and multiple weak interactions balance the interplay between RNA binding and phase separation of SARS-CoV-2 nucleocapsid. PNAS NEXUS 2023; 2:pgad333. [PMID: 37901441 PMCID: PMC10605006 DOI: 10.1093/pnasnexus/pgad333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Accepted: 10/02/2023] [Indexed: 10/31/2023]
Abstract
The nucleocapsid (N) protein of SARS-CoV-2 binds viral RNA, condensing it inside the virion, and phase separating with RNA to form liquid-liquid condensates. There is little consensus on what differentiates sequence-independent N-RNA interactions in the virion or in liquid droplets from those with specific genomic RNA (gRNA) motifs necessary for viral function inside infected cells. To identify the RNA structures and the N domains responsible for specific interactions and phase separation, we use the first 1,000 nt of viral RNA and short RNA segments designed as models for single-stranded and paired RNA. Binding affinities estimated from fluorescence anisotropy of these RNAs to the two-folded domains of N (the NTD and CTD) and comparison to full-length N demonstrate that the NTD binds preferentially to single-stranded RNA, and while it is the primary RNA-binding site, it is not essential to phase separation. Nuclear magnetic resonance spectroscopy identifies two RNA-binding sites on the NTD: a previously characterized site and an additional although weaker RNA-binding face that becomes prominent when binding to the primary site is weak, such as with dsRNA or a binding-impaired mutant. Phase separation assays of nucleocapsid domains with double-stranded and single-stranded RNA structures support a model where multiple weak interactions, such as with the CTD or the NTD's secondary face promote phase separation, while strong, specific interactions do not. These studies indicate that both strong and multivalent weak N-RNA interactions underlie the multifunctional abilities of N.
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Affiliation(s)
- Aidan B Estelle
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA
| | - Heather M Forsythe
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA
| | - Zhen Yu
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA
| | - Kaitlyn Hughes
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA
| | - Brittany Lasher
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA
| | - Patrick Allen
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA
| | - Patrick N Reardon
- Oregon State University NMR Facility, Oregon State University, Corvallis, OR 97331, USA
| | - David A Hendrix
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA
- School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR 97331, USA
| | - Elisar J Barbar
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA
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14
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Tants JN, Schlundt A. Advances, Applications, and Perspectives in Small-Angle X-ray Scattering of RNA. Chembiochem 2023; 24:e202300110. [PMID: 37466350 DOI: 10.1002/cbic.202300110] [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: 02/10/2023] [Revised: 04/22/2023] [Indexed: 07/20/2023]
Abstract
RNAs exhibit a plethora of functions far beyond transmitting genetic information. Often, RNA functions are entailed in their structure, be it as a regulatory switch, protein binding site, or providing catalytic activity. Structural information is a prerequisite for a full understanding of RNA-regulatory mechanisms. Owing to the inherent dynamics, size, and instability of RNA, its structure determination remains challenging. Methods such as NMR spectroscopy, X-ray crystallography, and cryo-electron microscopy can provide high-resolution structures; however, their limitations make structure determination, even for small RNAs, cumbersome, if at all possible. Although at a low resolution, small-angle X-ray scattering (SAXS) has proven valuable in advancing structure determination of RNAs as a complementary method, which is also applicable to large-sized RNAs. Here, we review the technological and methodological advancements of RNA SAXS. We provide examples of the powerful inclusion of SAXS in structural biology and discuss possible future applications to large RNAs.
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Affiliation(s)
- Jan-Niklas Tants
- Goethe University Frankfurt, Institute for Molecular Biosciences and Biomagnetic Resonance Centre (BMRZ), Max-von-Laue-Str. 9, 60438, Frankfurt, Germany
| | - Andreas Schlundt
- Goethe University Frankfurt, Institute for Molecular Biosciences and Biomagnetic Resonance Centre (BMRZ), Max-von-Laue-Str. 9, 60438, Frankfurt, Germany
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