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1.
Sci Rep ; 13(1): 2890, 2023 02 18.
Article in English | MEDLINE | ID: covidwho-2268916

ABSTRACT

Replication of the coronavirus genome starts with the formation of viral RNA-containing double-membrane vesicles (DMV) following viral entry into the host cell. The multi-domain nonstructural protein 3 (nsp3) is the largest protein encoded by the known coronavirus genome and serves as a central component of the viral replication and transcription machinery. Previous studies demonstrated that the highly-conserved C-terminal region of nsp3 is essential for subcellular membrane rearrangement, yet the underlying mechanisms remain elusive. Here we report the crystal structure of the CoV-Y domain, the most C-terminal domain of the SARS-CoV-2 nsp3, at 2.4 Å-resolution. CoV-Y adopts a previously uncharacterized V-shaped fold featuring three distinct subdomains. Sequence alignment and structure prediction suggest that this fold is likely shared by the CoV-Y domains from closely related nsp3 homologs. NMR-based fragment screening combined with molecular docking identifies surface cavities in CoV-Y for interaction with potential ligands and other nsps. These studies provide the first structural view on a complete nsp3 CoV-Y domain, and the molecular framework for understanding the architecture, assembly and function of the nsp3 C-terminal domains in coronavirus replication. Our work illuminates nsp3 as a potential target for therapeutic interventions to aid in the on-going battle against the COVID-19 pandemic and diseases caused by other coronaviruses.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/metabolism , Molecular Docking Simulation , Pandemics , Protein Domains , Viral Nonstructural Proteins/genetics
2.
Angewandte Chemie ; 135(14):1-6, 2023.
Article in English | Academic Search Complete | ID: covidwho-2257696

ABSTRACT

Der Ausbruch von COVID‐19 im Dezember 2019 erforderte eine Koordination wissenschaftlicher Beiträge zum Verständnis und zur Bekämpfung des Virus und führte so zur Bildung internationaler Forschungskonsortien. In diesem Viewpoint Article erläutern wir, wie sich die NMR‐Community versammelt hat, um sowohl das Genom als auch das Proteom von SARS‐CoV‐2 strukturell zu untersuchen und für beide die Bindung an niedermolekulare Verbindungen zu testen. Externe Faktoren, einschließlich längerfristiger Lockdowns aufgrund der Pandemie, begünstigten den Übergang von lokaler, auf einzelne Forschungsgruppen ausgerichteter Verbundforschung hin zu hochkoordinierter Forschung mit über 50 Gruppen aus 18 Ländern, die durch digitale Austauschformate unmittelbar gemeinsam Daten analysierten und unveröffentlichte Ergebnisse diskutierten und darüber hinaus Proben untereinander teilten. Wir diskutieren hier einige wichtige Lehren, die nach dem Ende der Pandemie gezogen werden sollten, und Herausforderungen, die es anzugehen gilt. (German) [ FROM AUTHOR] Copyright of Angewandte Chemie is the property of John Wiley & Sons, Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

3.
Angew Chem Int Ed Engl ; 62(14): e202217171, 2023 03 27.
Article in English | MEDLINE | ID: covidwho-2229623

ABSTRACT

The outbreak of COVID-19 in December 2019 required the formation of international consortia for a coordinated scientific effort to understand and combat the virus. In this Viewpoint Article, we discuss how the NMR community has gathered to investigate the genome and proteome of SARS-CoV-2 and tested them for binding to low-molecular-weight binders. External factors including extended lockdowns due to the global pandemic character of the viral infection triggered the transition from locally focused collaborative research conducted within individual research groups to digital exchange formats for immediate discussion of unpublished results and data analysis, sample sharing, and coordinated research between more than 50 groups from 18 countries simultaneously. We discuss key lessons that might pertain after the end of the pandemic and challenges that we need to address.


Subject(s)
COVID-19 , Humans , SARS-CoV-2 , Communicable Disease Control , Magnetic Resonance Spectroscopy , Magnetic Resonance Imaging
4.
Berg, Hannes, Wirtz Martin, Maria A.; Altincekic, Nadide, Islam, Alshamleh, Bains, Jasleen Kaur, Blechar, Julius, Ceylan, Betül, de Jesus, Vanessa, Karthikeyan, Dhamotharan, Fuks, Christin, Gande, Santosh L.; Hargittay, Bruno, Hohmann, Katharina F.; Hutchison, Marie T.; Korn, Sophie Marianne, Krishnathas, Robin, Kutz, Felicitas, Linhard, Verena, Matzel, Tobias, Meiser, Nathalie, Niesteruk, Anna, Pyper, Dennis J.; Schulte, Linda, Trucks, Sven, Azzaoui, Kamal, Blommers, Marcel J. J.; Gadiya, Yojana, Karki, Reagon, Zaliani, Andrea, Gribbon, Philip, Marcius da Silva, Almeida, Cristiane Dinis, Anobom, Bula, Anna L.; Bütikofer, Matthias, Caruso, Ícaro Putinhon, Felli, Isabella Caterina, Da Poian, Andrea T.; Gisele Cardoso de, Amorim, Fourkiotis, Nikolaos K.; Gallo, Angelo, Ghosh, Dhiman, Francisco, Gomes‐Neto, Gorbatyuk, Oksana, Hao, Bing, Kurauskas, Vilius, Lecoq, Lauriane, Li, Yunfeng, Nathane Cunha, Mebus‐Antunes, Mompeán, Miguel, Thais Cristtina, Neves‐Martins, Martí, Ninot‐Pedrosa, Pinheiro, Anderson S.; Pontoriero, Letizia, Pustovalova, Yulia, Riek, Roland, Robertson, Angus J.; Abi Saad, Marie Jose, Treviño, Miguel Á, Tsika, Aikaterini C.; Almeida, Fabio C. L.; Bax, Ad, Katherine, Henzler‐Wildman, Hoch, Jeffrey C.; Jaudzems, Kristaps, Laurents, Douglas V.; Orts, Julien, Pierattelli, Roberta, Spyroulias, Georgios A.; Elke, Duchardt‐Ferner, Ferner, Jan, Fürtig, Boris, Hengesbach, Martin, Löhr, Frank, Qureshi, Nusrat, Richter, Christian, Saxena, Krishna, Schlundt, Andreas, Sreeramulu, Sridhar, Wacker, Anna, Weigand, Julia E.; Julia, Wirmer‐Bartoschek, Wöhnert, Jens, Schwalbe, Harald.
Angewandte Chemie ; 134(46), 2022.
Article in English | ProQuest Central | ID: covidwho-2103465

ABSTRACT

SARS‐CoV‐2 (SCoV2) and its variants of concern pose serious challenges to the public health. The variants increased challenges to vaccines, thus necessitating for development of new intervention strategies including anti‐virals. Within the international Covid19‐NMR consortium, we have identified binders targeting the RNA genome of SCoV2. We established protocols for the production and NMR characterization of more than 80 % of all SCoV2 proteins. Here, we performed an NMR screening using a fragment library for binding to 25 SCoV2 proteins and identified hits also against previously unexplored SCoV2 proteins. Computational mapping was used to predict binding sites and identify functional moieties (chemotypes) of the ligands occupying these pockets. Striking consensus was observed between NMR‐detected binding sites of the main protease and the computational procedure. Our investigation provides novel structural and chemical space for structure‐based drug design against the SCoV2 proteome.

5.
J Mol Biol ; 434(16): 167720, 2022 08 30.
Article in English | MEDLINE | ID: covidwho-2028233

ABSTRACT

Viral infection in cells triggers a cascade of molecular defense mechanisms to maintain host-cell homoeostasis. One of these mechanisms is ADP-ribosylation, a fundamental post-translational modification (PTM) characterized by the addition of ADP-ribose (ADPr) on substrates. Poly(ADP-ribose) polymerases (PARPs) are implicated in this process and they perform ADP-ribosylation on host and pathogen proteins. Some viral families contain structural motifs that can reverse this PTM. These motifs known as macro domains (MDs) are evolutionarily conserved protein domains found in all kingdoms of life. They are divided in different classes with the viral belonging to Macro-D-type class because of their properties to recognize and revert the ADP-ribosylation. Viral MDs are potential pharmaceutical targets, capable to counteract host immune response. Sequence and structural homology between viral and human MDs are an impediment for the development of new active compounds against their function. Remdesivir, is a drug administrated in viral infections inhibiting viral replication through RNA-dependent RNA polymerase (RdRp). Herein, GS-441524, the active metabolite of the remdesivir, is tested as a hydrolase inhibitor for several viral MDs and for its binding to human homologs found in PARPs. This study presents biochemical and biophysical studies, which indicate that GS-441524 selectively modifies SARS-CoV-2 MD de-MARylation activity, while it does not interact with hPARP14 MD2 and hPARP15 MD2. The structural investigation of MD•GS-441524 complexes, using solution NMR and X-ray crystallography, discloses the impact of certain amino acids in ADPr binding cavity suggesting that F360 and its adjacent residues tune the selective binding of the inhibitor to SARS-CoV-2 MD.


Subject(s)
ADP-Ribosylation , Adenosine/analogs & derivatives , Coronavirus Protease Inhibitors , Poly(ADP-ribose) Polymerases , SARS-CoV-2 , ADP-Ribosylation/drug effects , Adenosine/chemistry , Adenosine/pharmacology , Adenosine Diphosphate Ribose/chemistry , Coronavirus Protease Inhibitors/chemistry , Coronavirus Protease Inhibitors/pharmacology , Humans , Poly(ADP-ribose) Polymerases/chemistry , Protein Binding , Protein Domains , SARS-CoV-2/drug effects , SARS-CoV-2/enzymology
6.
Biomol NMR Assign ; 16(1): 17-25, 2022 04.
Article in English | MEDLINE | ID: covidwho-1827073

ABSTRACT

The ongoing pandemic of the respiratory disease COVID-19 is caused by the SARS-CoV-2 (SCoV2) virus. SCoV2 is a member of the Betacoronavirus genus. The 30 kb positive sense, single stranded RNA genome of SCoV2 features 5'- and 3'-genomic ends that are highly conserved among Betacoronaviruses. These genomic ends contain structured cis-acting RNA elements, which are involved in the regulation of viral replication and translation. Structural information about these potential antiviral drug targets supports the development of novel classes of therapeutics against COVID-19. The highly conserved branched stem-loop 5 (SL5) found within the 5'-untranslated region (5'-UTR) consists of a basal stem and three stem-loops, namely SL5a, SL5b and SL5c. Both, SL5a and SL5b feature a 5'-UUUCGU-3' hexaloop that is also found among Alphacoronaviruses. Here, we report the extensive 1H, 13C and 15N resonance assignment of the 37 nucleotides (nts) long sequence spanning SL5b and SL5c (SL5b + c), as basis for further in-depth structural studies by solution NMR spectroscopy.


Subject(s)
COVID-19 , SARS-CoV-2 , 5' Untranslated Regions , Humans , Magnetic Resonance Spectroscopy , Nuclear Magnetic Resonance, Biomolecular
7.
ChemPhysChem ; 23(4):e202200048, 2022.
Article in English | Wiley | ID: covidwho-1704901

ABSTRACT

The Cover Feature illustrates how artifact-free 2D NOE correlations between labile protons can be obtained from an extended Hadamard encoding/decoding matrix, which supersedes problems in conventional Hadamard schemes. The sensitivity-enhancing abilities of extended Hadamard encoding operating in conjunction with solvent repolarization mechanisms are demonstrated on GHz NMR studies on SARS-CoV-2 RNA fragments. More information can be found in the Article by Lucio Frydman and co-workers.

8.
Chemphyschem ; 23(4): e202100704, 2022 02 16.
Article in English | MEDLINE | ID: covidwho-1589144

ABSTRACT

Hadamard encoded saturation transfer can significantly improve the efficiency of NOE-based NMR correlations from labile protons in proteins, glycans and RNAs, increasing the sensitivity of cross-peaks by an order of magnitude and shortening experimental times by ≥100-fold. These schemes, however, fail when tackling correlations within a pool of labile protons - for instance imino-imino correlations in RNAs or amide-amide correlations in proteins. Here we analyze the origin of the artifacts appearing in these experiments and propose a way to obtain artifact-free correlations both within the labile pool as well as between labile and non-labile 1 Hs, while still enjoying the gains arising from Hadamard encoding and solvent repolarizations. The principles required for implementing what we define as the extended Hadamard scheme are derived, and its clean, artifact-free, sensitivity-enhancing performance is demonstrated on RNA fragments derived from the SARS-CoV-2 genome. Sensitivity gains per unit time approaching an order of magnitude are then achieved in both imino-imino and imino-amino/aromatic protons 2D correlations; similar artifact-free sensitivity gains can be observed when carrying out extended Hadamard encodings of 3D NOESY/HSQC-type experiments. The resulting spectra reveal significantly more correlations than their conventionally acquired counterparts, which can support the spectral assignment and secondary structure determination of structured RNA elements.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Magnetic Resonance Spectroscopy/methods , Proteins/chemistry , RNA
9.
Biomol NMR Assign ; 15(2): 467-474, 2021 10.
Article in English | MEDLINE | ID: covidwho-1442185

ABSTRACT

The stem-loop (SL1) is the 5'-terminal structural element within the single-stranded SARS-CoV-2 RNA genome. It is formed by nucleotides 7-33 and consists of two short helical segments interrupted by an asymmetric internal loop. This architecture is conserved among Betacoronaviruses. SL1 is present in genomic SARS-CoV-2 RNA as well as in all subgenomic mRNA species produced by the virus during replication, thus representing a ubiquitous cis-regulatory RNA with potential functions at all stages of the viral life cycle. We present here the 1H, 13C and 15N chemical shift assignment of the 29 nucleotides-RNA construct 5_SL1, which denotes the native 27mer SL1 stabilized by an additional terminal G-C base-pair.


Subject(s)
5' Untranslated Regions , Nuclear Magnetic Resonance, Biomolecular , SARS-CoV-2/genetics , Nucleic Acid Conformation , RNA, Spliced Leader
10.
Biomol NMR Assign ; 15(2): 335-340, 2021 10.
Article in English | MEDLINE | ID: covidwho-1442184

ABSTRACT

The SARS-CoV-2 virus is the cause of the respiratory disease COVID-19. As of today, therapeutic interventions in severe COVID-19 cases are still not available as no effective therapeutics have been developed so far. Despite the ongoing development of a number of effective vaccines, therapeutics to fight the disease once it has been contracted will still be required. Promising targets for the development of antiviral agents against SARS-CoV-2 can be found in the viral RNA genome. The 5'- and 3'-genomic ends of the 30 kb SCoV-2 genome are highly conserved among Betacoronaviruses and contain structured RNA elements involved in the translation and replication of the viral genome. The 40 nucleotides (nt) long highly conserved stem-loop 4 (5_SL4) is located within the 5'-untranslated region (5'-UTR) important for viral replication. 5_SL4 features an extended stem structure disrupted by several pyrimidine mismatches and is capped by a pentaloop. Here, we report extensive 1H, 13C, 15N and 31P resonance assignments of 5_SL4 as the basis for in-depth structural and ligand screening studies by solution NMR spectroscopy.


Subject(s)
5' Untranslated Regions , Nuclear Magnetic Resonance, Biomolecular , SARS-CoV-2/genetics , Inverted Repeat Sequences/genetics
11.
Biomol NMR Assign ; 15(2): 287-295, 2021 10.
Article in English | MEDLINE | ID: covidwho-1442183

ABSTRACT

The current COVID-19 pandemic caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has become a worldwide health crisis, necessitating coordinated scientific research and urgent identification of new drug targets for treatment of COVID-19 lung disease. The covid19-nmr consortium seeks to support drug development by providing publicly accessible NMR data on the viral RNA elements and proteins. The SARS-CoV-2 genome comprises a single RNA of about 30 kb in length, in which 14 open reading frames (ORFs) have been annotated, and encodes approximately 30 proteins. The first two-thirds of the SARS-CoV-2 genome is made up of two large overlapping open-reading-frames (ORF1a and ORF1b) encoding a replicase polyprotein, which is subsequently cleaved to yield 16 so-called non-structural proteins. The non-structural protein 1 (Nsp1), which is considered to be a major virulence factor, suppresses host immune functions by associating with host ribosomal complexes at the very end of its C-terminus. Furthermore, Nsp1 facilitates initiation of viral RNA translation via an interaction of its N-terminal domain with the 5' untranslated region (UTR) of the viral RNA. Here, we report the near-complete backbone chemical-shift assignments of full-length SARS-CoV-2 Nsp1 (19.8 kDa), which reveal the domain organization, secondary structure and backbone dynamics of Nsp1, and which will be of value to further NMR-based investigations of both the biochemical and physiological functions of Nsp1.


Subject(s)
Nuclear Magnetic Resonance, Biomolecular , SARS-CoV-2 , Viral Nonstructural Proteins/chemistry , Models, Molecular , Protein Domains
12.
Angew Chem Weinheim Bergstr Ger ; 133(21): 11991-11998, 2021 May 17.
Article in English | MEDLINE | ID: covidwho-1381836

ABSTRACT

2D NOESY plays a central role in structural NMR spectroscopy. We have recently discussed methods that rely on solvent-driven exchanges to enhance NOE correlations between exchangeable and non-exchangeable protons in nucleic acids. Such methods, however, fail when trying to establish connectivities within pools of labile protons. This study introduces an alternative that also enhances NOEs between such labile sites, based on encoding a priori selected peaks by selective saturations. The resulting selective magnetization transfer (SMT) experiment proves particularly useful for enhancing the imino-imino cross-peaks in RNAs, which is a first step in the NMR resolution of these structures. The origins of these enhancements are discussed, and their potential is demonstrated on RNA fragments derived from the genome of SARS-CoV-2, recorded with better sensitivity and an order of magnitude faster than conventional 2D counterparts.

13.
J Am Chem Soc ; 143(13): 4942-4948, 2021 04 07.
Article in English | MEDLINE | ID: covidwho-1387161

ABSTRACT

Multidimensional NOESY experiments targeting correlations between exchangeable imino and amino protons provide valuable information about base pairing in nucleic acids. It has been recently shown that the sensitivity of homonuclear correlations involving RNA's labile imino protons can be significantly enhanced, by exploiting the repolarization brought about by solvent exchanges. Homonuclear correlations, however, are of limited spectral resolution, and usually incapable of tackling relatively large homopolymers with repeating structures like RNAs. This study presents a heteronuclear-resolved version of those NOESY experiments, in which magnetization transfers between the aqueous solvent and the nucleic acid protons are controlled by selecting specific chemical shift combinations of a coupled 1H-15N spin pair. This selective control effectively leads to a pseudo-3D version of HSQC-NOESY, but with cross-peaks enhanced by ∼2-5× as compared with conventional 2D NOESY counterparts. The enhanced signal sensitivity as well as access to both 15N-1H and 1H-1H NOESY dimensions can greatly facilitate RNA assignments and secondary structure determinations, as demonstrated here with the analysis of genome fragments derived from the SARS-CoV-2 virus.


Subject(s)
Magnetic Phenomena , Magnetic Resonance Spectroscopy , RNA, Viral/chemistry , SARS-CoV-2/genetics , Temperature
14.
Biomol NMR Assign ; 15(1): 165-171, 2021 04.
Article in English | MEDLINE | ID: covidwho-1384622

ABSTRACT

SARS-CoV-2 RNA, nsP3c (non-structural Protein3c) spans the sequence of the so-called SARS Unique Domains (SUDs), first observed in SARS-CoV. Although the function of this viral protein is not fully elucidated, it is believed that it is crucial for the formation of the replication/transcription viral complex (RTC) and of the interaction of various viral "components" with the host cell; thus, it is essential for the entire viral life cycle. The first two SUDs, the so-called SUD-N (the N-terminal domain) and SUD-M (domain following SUD-N) domains, exhibit topological and conformational features that resemble the nsP3b macro (or "X") domain. Indeed, they are all folded in a three-layer α/ß/α sandwich structure, as revealed through crystallographic structural investigation of SARS-CoV SUDs, and they have been attributed to different substrate selectivity as they selectively bind to oligonucleotides. On the other hand, the C-terminal SUD (SUD-C) exhibit much lower sequence similarities compared to the SUD-N & SUD-M, as reported in previous crystallographic and NMR studies of SARS-CoV. In the absence of the 3D structures of SARS-CoV-2, we report herein the almost complete NMR backbone and side-chain resonance assignment (1H,13C,15N) of SARS-CoV-2 SUD-M and SUD-C proteins, and the NMR chemical shift-based prediction of their secondary structure elements. These NMR data will set the base for further understanding at the atomic-level conformational dynamics of these proteins and will allow the effective screening of a large number of small molecules as binders with potential biological impact on their function.


Subject(s)
Coronavirus Papain-Like Proteases/chemistry , Magnetic Resonance Spectroscopy , SARS-CoV-2/chemistry , Carbon Isotopes , Hydrogen , Nitrogen Isotopes , Protein Binding , Protein Domains , Protein Structure, Secondary
15.
Biomol NMR Assign ; 15(1): 85-89, 2021 04.
Article in English | MEDLINE | ID: covidwho-1384621

ABSTRACT

Among the proteins encoded by the SARS-CoV-2 RNA, nsP3 (non-structural Protein3) is the largest multi-domain protein. Its role is multifaceted and important for the viral life cycle. Nonetheless, regarding the specific role of each domain there are many aspects of their function that have to be investigated. SARS Unique Domains (SUDs), constitute the nsP3c region of the nsP3, and were observed for the first time in SARS-CoV. Two of them, namely SUD-N (the first SUD) and the SUD-M (sequential to SUD-N), exhibit structural homology with nsP3b ("X" or macro domain); indeed all of them are folded in a three-layer α/ß/α sandwich. On the contrary, they do not exhibit functional similarities, like ADP-ribose binding properties and ADP-ribose hydrolase activity. There are reports that suggest that these two SUDs may exhibit a binding selectivity towards G-oligonucleotides, a feature which may contribute to the characterization of their role in the formation of the replication/transcription viral complex (RTC) and of the interaction of various viral "components" with the host cell. While the structures of these domains of SARS-CoV-2 have not been determined yet, SUDs interaction with oligonucleotides and/or RNA molecules may provide a platform for drug discovery. Here, we report the almost complete NMR backbone and side-chain resonance assignment (1H,13C,15N) of SARS-CoV-2 SUD-N protein, and the NMR chemical shift-based prediction of the secondary structure elements. These data may be exploited for its 3D structure determination and the screening of chemical compounds libraries, which may alter SUD-N function.


Subject(s)
Coronavirus Papain-Like Proteases/chemistry , Magnetic Resonance Spectroscopy , SARS-CoV-2/chemistry , Carbon Isotopes , Drug Design , Hydrogen , Nitrogen Isotopes , Oligonucleotides/chemistry , Protein Domains , Protein Structure, Secondary , Virus Replication
16.
Angew Chem Int Ed Engl ; 60(21): 11884-11891, 2021 05 17.
Article in English | MEDLINE | ID: covidwho-1384108

ABSTRACT

2D NOESY plays a central role in structural NMR spectroscopy. We have recently discussed methods that rely on solvent-driven exchanges to enhance NOE correlations between exchangeable and non-exchangeable protons in nucleic acids. Such methods, however, fail when trying to establish connectivities within pools of labile protons. This study introduces an alternative that also enhances NOEs between such labile sites, based on encoding a priori selected peaks by selective saturations. The resulting selective magnetization transfer (SMT) experiment proves particularly useful for enhancing the imino-imino cross-peaks in RNAs, which is a first step in the NMR resolution of these structures. The origins of these enhancements are discussed, and their potential is demonstrated on RNA fragments derived from the genome of SARS-CoV-2, recorded with better sensitivity and an order of magnitude faster than conventional 2D counterparts.


Subject(s)
Nuclear Magnetic Resonance, Biomolecular/methods , Protons , RNA, Viral/analysis , SARS-CoV-2/chemistry , Magnetic Phenomena , RNA, Viral/chemistry
17.
Angew Chem Int Ed Engl ; 60(35): 19191-19200, 2021 08 23.
Article in English | MEDLINE | ID: covidwho-1279344

ABSTRACT

SARS-CoV-2 contains a positive single-stranded RNA genome of approximately 30 000 nucleotides. Within this genome, 15 RNA elements were identified as conserved between SARS-CoV and SARS-CoV-2. By nuclear magnetic resonance (NMR) spectroscopy, we previously determined that these elements fold independently, in line with data from in vivo and ex-vivo structural probing experiments. These elements contain non-base-paired regions that potentially harbor ligand-binding pockets. Here, we performed an NMR-based screening of a poised fragment library of 768 compounds for binding to these RNAs, employing three different 1 H-based 1D NMR binding assays. The screening identified common as well as RNA-element specific hits. The results allow selection of the most promising of the 15 RNA elements as putative drug targets. Based on the identified hits, we derive key functional units and groups in ligands for effective targeting of the RNA of SARS-CoV-2.


Subject(s)
Genome , RNA, Viral/metabolism , SARS-CoV-2/genetics , Small Molecule Libraries/metabolism , Drug Evaluation, Preclinical , Ligands , Molecular Structure , Nucleic Acid Conformation , Proton Magnetic Resonance Spectroscopy , RNA, Viral/chemistry , Small Molecule Libraries/chemistry
18.
Biomol NMR Assign ; 15(2): 235-241, 2021 10.
Article in English | MEDLINE | ID: covidwho-1146127

ABSTRACT

As part of an International consortium aiming at the characterization by NMR of the proteins of the SARS-CoV-2 virus, we have obtained the virtually complete assignment of the backbone atoms of the non-structural protein nsp9. This small (12 kDa) protein is encoded by ORF1a, binds to RNA and seems to be essential for viral RNA synthesis. The crystal structures of the SARS-CoV-2 protein and other homologues suggest that the protein is dimeric as also confirmed by analytical ultracentrifugation and dynamic light scattering. Our data constitute the prerequisite for further NMR-based characterization, and provide the starting point for the identification of small molecule lead compounds that could interfere with RNA binding and prevent viral replication.


Subject(s)
Nuclear Magnetic Resonance, Biomolecular , RNA-Binding Proteins/chemistry , Viral Nonstructural Proteins/chemistry , Hydrogen-Ion Concentration , Models, Molecular , Protein Structure, Secondary
19.
Biomol NMR Assign ; 15(1): 129-135, 2021 04.
Article in English | MEDLINE | ID: covidwho-1141504

ABSTRACT

The current outbreak of the highly infectious COVID-19 respiratory disease is caused by the novel coronavirus SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2). To fight the pandemic, the search for promising viral drug targets has become a cross-border common goal of the international biomedical research community. Within the international Covid19-NMR consortium, scientists support drug development against SARS-CoV-2 by providing publicly available NMR data on viral proteins and RNAs. The coronavirus nucleocapsid protein (N protein) is an RNA-binding protein involved in viral transcription and replication. Its primary function is the packaging of the viral RNA genome. The highly conserved architecture of the coronavirus N protein consists of an N-terminal RNA-binding domain (NTD), followed by an intrinsically disordered Serine/Arginine (SR)-rich linker and a C-terminal dimerization domain (CTD). Besides its involvement in oligomerization, the CTD of the N protein (N-CTD) is also able to bind to nucleic acids by itself, independent of the NTD. Here, we report the near-complete NMR backbone chemical shift assignments of the SARS-CoV-2 N-CTD to provide the basis for downstream applications, in particular site-resolved drug binding studies.


Subject(s)
Coronavirus Nucleocapsid Proteins/chemistry , Magnetic Resonance Spectroscopy , SARS-CoV-2/chemistry , Carbon Isotopes , Crystallography, X-Ray , Dimerization , Drug Design , Hydrogen , Hydrogen-Ion Concentration , Nitrogen Isotopes , Phosphoproteins/chemistry , Protein Binding , Protein Domains , Protein Interaction Mapping , Protein Structure, Secondary
20.
Biomol NMR Assign ; 15(1): 203-211, 2021 04.
Article in English | MEDLINE | ID: covidwho-1046684

ABSTRACT

The SARS-CoV-2 (SCoV-2) virus is the causative agent of the ongoing COVID-19 pandemic. It contains a positive sense single-stranded RNA genome and belongs to the genus of Betacoronaviruses. The 5'- and 3'-genomic ends of the 30 kb SCoV-2 genome are potential antiviral drug targets. Major parts of these sequences are highly conserved among Betacoronaviruses and contain cis-acting RNA elements that affect RNA translation and replication. The 31 nucleotide (nt) long highly conserved stem-loop 5a (SL5a) is located within the 5'-untranslated region (5'-UTR) important for viral replication. SL5a features a U-rich asymmetric bulge and is capped with a 5'-UUUCGU-3' hexaloop, which is also found in stem-loop 5b (SL5b). We herein report the extensive 1H, 13C and 15N resonance assignment of SL5a as basis for in-depth structural studies by solution NMR spectroscopy.


Subject(s)
5' Untranslated Regions , Coronavirus Papain-Like Proteases/chemistry , Magnetic Resonance Spectroscopy , SARS-CoV-2/chemistry , SARS-CoV-2/genetics , Carbon Isotopes , Genes, Viral , Hydrogen , Nitrogen Isotopes , Protein Binding , Protein Domains , Protein Structure, Secondary
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