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1.
BMC Infect Dis ; 22(1): 280, 2022 Mar 23.
Article in English | MEDLINE | ID: covidwho-1789103

ABSTRACT

BACKGROUND: Deep neck space abscess (DNSA) is a serious infection in the head and neck. Antibiotic therapy is an important treatment in patients with DNSA. However, the results of bacterial culture need at least 48 h, and the positive rate is only 30-50%, indicating that the use of empiric antibiotic treatment for most patients with DNSA should at least 48 h or even throughout the whole course of treatment. Thus, how to use empiric antibiotics has always been a problem for clinicians. This study analyzed the distribution of bacteria based on disease severity and clinical characteristics of DNSA patients, and provides bacteriological guidance for the empiric use of antibiotics. METHODS: We analyzed 433 patients with DNSA who were diagnosed and treated at nine medical centers in Guangdong Province between January 1, 2015, and December 31, 2020. A nomogram for disease severity (mild/severe) was constructed using least absolute shrinkage and selection operator-logistic regression analysis. Clinical characteristics for the Gram reaction of the strain were identified using multivariate analyses. RESULTS: 92 (21.2%) patients developed life-threatening complications. The nomogram for disease severity comprised of seven predictors. The area under the receiver operating characteristic curves of the nomogram in the training and validation cohorts were 0.951 and 0.931, respectively. In the mild cases, 43.2% (101/234) had positive culture results (49% for Gram-positive and 51% for Gram-negative strains). The positive rate of cultures in the patients with severe disease was 63% (58/92, 37.9% for Gram-positive, and 62.1% for Gram-negative strains). Diabetes mellitus was an independent predictor of Gram-negative strains in the mild disease group, whereas gas formation and trismus were independent predictors of Gram-positive strains in the severe disease group. The positivity rate of multidrug-resistant strains was higher in the severe disease group (12.1%) than in the mild disease group (1.0%) (P < 0.001). Metagenomic sequencing was helpful for the bacteriological diagnosis of DNSA by identifying anaerobic strains (83.3%). CONCLUSION: We established a DNSA clinical severity prediction model and found some predictors for the type of Gram-staining strains in different disease severity cases. These results can help clinicians in effectively choosing an empiric antibiotic treatment.


Subject(s)
Abscess , Neck , Abscess/drug therapy , Abscess/microbiology , Anti-Bacterial Agents/therapeutic use , Humans , Metagenomics , Neck/microbiology , Severity of Illness Index
2.
iScience ; 2022.
Article in English | EuropePMC | ID: covidwho-1755857

ABSTRACT

The global pandemic of COVID-19 caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection confers great threat to the public health. Human breastmilk is a complex with nutritional composition to nourish infants and protect them from different kinds of infectious diseases including COVID-19. Here, we identified lactoferrin (LF), mucin1 (MUC1) and α-lactalbumin (α-LA) from human breastmilk inhibit SARS-CoV-2 infection using a SARS-CoV-2 pseudovirus system and transcription and replication-competent SARS-CoV-2 virus-like-particles (trVLP). Additionally, LF and MUC1 inhibited multiple steps including viral attachment, entry and post-entry replication, while α-LA inhibited viral attachment and entry. Importantly, LF, MUC1 and α-LA possessed potent antiviral activities towards variants such as B.1.1.7 (alpha), B.1.351 (beta), P.1 (gamma) and B.1.617.1 (kappa). Taken together, our study provides evidence that human breastmilk components (LF, MUC1 and α-LA) are promising antiviral and potential therapeutic candidates warranting further development or treating COVID-19. Graphical

3.
Nano today ; 2022.
Article in English | EuropePMC | ID: covidwho-1749472

ABSTRACT

While gold compound have been approved for Rheumatoid arthritis treatment as it well suppresses inflammatory cytokines of patients, no such treatment is currently available for COVID-19 treatment in vivo. We firstly disclose gold cluster yields better therapeutic outcome than Remdesivir in COVID-19 hamster treatments as it is armed with direct inhibition viral replication and intrinsic suppression inflammatory cytokines expression. Crystal data reveals that Au (I), released from gold cluster (GA), covalently binds thiolate of Cys145 of SARS-CoV-2 Mpro. GA directly decreases SARS-CoV-2 viral replication and intrinsically down-regulates NFκB pathway therefore significantly inhibiting expression of inflammatory cytokines in cells. The inflammatory cytokines in GA-treated COVID-19 transgenic mice are found to be significantly lower than that of control mice. When COVID-19 golden hamsters are treated by GA, the lung inflammatory cytokines levels are significantly lower than that of Remdesivir. The pathological results show that GA treatment significantly reduce lung inflammatory injuries when compared to that of Remdesivir-treated COVID-19 hamsters. Graphical

4.
Int J Prod Econ ; 245: 108396, 2022 Mar.
Article in English | MEDLINE | ID: covidwho-1699431

ABSTRACT

Although many firms are actively deploying various digital technology (DT) assets across their supply chains to mitigate the negative impact of the COVID-19 pandemic on operations, whether these DT assets are truly helpful remains unclear. To disentangle this puzzle, we investigate whether firms that have higher levels of DT asset deployment achieve better supply chain performance in the COVID-19 crisis than firms with lower levels. From an asset orchestration perspective, we focus on two dimensions of DT asset deployment: breadth and depth, which reflect the scope and scale of DT assets, respectively. The empirical results from 175 Chinese firms that have deployed DT assets to varying degrees reveal that both the breadth and the depth of DT asset deployment show positive relationships with supply chain visibility. In contrast, the depth but not the breadth of DT asset deployment poses a positive relationship with supply chain agility. Most importantly, high levels of supply chain visibility and supply chain agility were prerequisites for excellent supply chain performance in the COVID-19 crisis. We contribute to the digital supply chain management literature by uncovering the mechanism through which DT asset deployment generates impacts on supply chain performance from an asset orchestration perspective. Our study also assists firms in improving their digital transformation strategies to combat the COVID-19 pandemic.

5.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-324240

ABSTRACT

Human steroid 5α-reductase 2 (SRD5α2) as a critical integral membrane enzyme in steroid metabolism catalyzes testosterone to dihydrotestosterone. Mutations on its gene have been linked to 5α-reductase deficiency and prostate cancer. Finasteride and dutasteride as SRD5α2 inhibitors are widely used anti-androgen drugs for benign prostate hyperplasia, which have recently been indicated in the treatment of COVID-19. The molecular mechanisms underlying enzyme catalysis and inhibition remained elusive for SRD5α2 and other eukaryotic integral membrane steroid reductases due to a lack of structural information. Here, we report a crystal structure of human SRD5α2 at 2.8 Å revealing a unique 7-TM structural topology and an intermediate adduct of finasteride and NADPH as NADP-dihydrofinasteride in a largely enclosed binding cavity inside the membrane. Structural analysis together with computational and mutagenesis studies reveals molecular mechanisms for the 5α-reduction of testosterone and the finasteride inhibition involving residues E57 and Y91. Molecular dynamics simulation results indicate high conformational dynamics of the cytosolic region regulating the NADPH/NADP + exchange. Mapping disease-causing mutations of SRD5α2 to our structure suggests molecular mechanisms for their pathological effects. Our results offer critical structural insights into the function of integral membrane steroid reductases and will facilitate drug development.

6.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-323657

ABSTRACT

The ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, previously designated as 2019-nCoV) outbreak has caused global concern1. Currently, there are no clinically approved specific drugs or vaccines available for this virus. The viral polymerase is a promising target for developing broad- spectrum antiviral drugs. Here, based on the highly similar structure of SARS- CoV non-structural protein 12 (nsp12) polymerase subunit2, we applied virtual screen for the available compounds, including both the FDA-approved and under- clinic drugs, to identify potential antiviral molecules against SARS-CoV-2. We found two drugs, the clinically approved anti-fungi drug Caspofungin Acetate (Cancidas) and the oncolytic peptide LTX-315, can bind SARS-CoV-2 nsp12 protein to block the polymerase activity in vitro . Further live virus assay revealed that both Caspofungin Acetate and LTX-315 can effectively inhibit SARS-CoV-2 replication in vero cells. These findings present promising drug candidates for treatment of related diseases and would also stimulate the development of pan- coronavirus antiviral agents.Authors Min Wang, Fei Ye, Jiaqi Su, Jingru Zhao, and Bin Yuan contributed equally to this work.

7.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-319475

ABSTRACT

Background: The severity of COVID-19 associates with the clinical decision making and the prognosis of COVID-19 patients, therefore, early identification of patients who are likely to develop severe or critical COVID-19 is critical in clinical practice. The aim of this study was to screen severity-associated markers and construct an assessment model for predicting the severity of COVID-19. Methods: : 172 confirmed COVID-19 patients were enrolled from two designated hospitals in Hangzhou, China. Ordinal logistic regression was used to screen severity-associated markers. Least Absolute Shrinkage and Selection Operator (LASSO) regression was performed for further feature selection. Assessment models were constructed using logistic regression, ridge regression, support vector machine and random forest. The area under the receiver operator characteristic curve (AUROC) was used to evaluate the performance of different models. Internal validation was performed by using bootstrap with 500 re-sampling in the training set, and external validation was performed in the validation set for the four models, respectively. Results: : Age, comorbidity, fever, and 18 laboratory markers were associated with the severity of COVID-19 (all P values <0.05). By LASSO regression, eight markers were included for the assessment model construction. The ridge regression model had the best performance with AUROCs of 0.930 (95% CI, 0.914-0.943) and 0.827 (95% CI, 0.716-0.921) in the internal and external validations, respectively. A risk score, established based on the ridge regression model, had good discrimination in all patients with an AUROC of 0.897 (95% CI 0.845-0.940), and a well-fitted calibration curve. Using the optimal cutoff value of 71, the sensitivity and specificity were 87.1% and 78.1%, respectively. A web-based assessment system was developed based on the risk score. Conclusions: : Eight clinical markers of lactate dehydrogenase, C-reactive protein, albumin, comorbidity, electrolyte disturbance, coagulation function, eosinophil and lymphocyte counts were associated with the severity of COVID-19. An assessment model constructed with these eight markers would help the clinician to evaluate the likelihood of developing severity of COVID-19 at admission and early take measures on clinical treatment.

8.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-307709

ABSTRACT

Background: Nucleic acid amplification is the main method used to detect infections of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the false-negative rate of nucleic acid tests cannot be ignored. Methods: : Herein, we demonstrated genomic variations at the target sequences for the tests and the geographical distribution of the variations across countries by analyzing the whole-genome sequencing data of SARS-CoV-2 strains from the 2019 Novel Coronavirus Resource (2019nCoVR) database. Results: : Among the 21 pairs of primer sequences in regions ORF1ab, S, E, and N, the total length of primer and probe target sequences was 938bp, with 131(13.97%) variant loci in 2415 (38.96%) isolates. Primer targets in the N region contained the most variations that were distributed among the most isolates, and the E region contained the least. Single nucleotide polymorphisms were the most frequent variation, with C to T transitions being detected in the most variant loci. G to A transitions and G to C transversions were the most common and had the highest isolate density. Genomic variations at the three mutation sites N: 28881, N: 28882, and N: 28883 were the most commonly detected, including in 608 SARS-CoV-2 strains from 33 countries, especially in the United Kingdom, Portugal, and Belgium. Conclusions: : Our work comprehensively analyzed genomic variations on the target sequences of the nucleic acid amplification tests, offering evidence to optimize primer and probe target sequence selection, thereby improving the performance of the SARS-CoV-2 diagnostic test.

9.
ACS Med Chem Lett ; 12(11): 1838-1844, 2021 Nov 11.
Article in English | MEDLINE | ID: covidwho-1507014

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has stimulated the search for effective drugs for its prevention and treatment. Natural products are an important source for new drug discovery. Here, we report that, NK007(S,R), a tylophorine malate, displays high antiviral activity against SARS-CoV-2 with an EC50 0.03 µM in vitro, which is substantially lower than that of remdesivir (EC50: 0.8 µM in vitro), the only authorized drug to date. The histopathological research revealed that NK007(S,R) (5 mg/kg/dose) displayed a protection effect in lung injury induced by SARS-CoV-2, which is better than remdesivir (25 mg/kg/dose). We also prepared two nanosized preparations of NK007(S,R), which also showed good efficacy (EC50: NP-NK007, 0.007 µM in vitro; LP-NK007, 0.014 µM in vitro). Our findings suggest that tylophora alkaloids, isolated from the traditional Chinese medicine Cynanchum komarovii AL, offer a new skeleton for the development of anticoronavirus drug candidate.

10.
Cancer Med ; 10(23): 8432-8450, 2021 12.
Article in English | MEDLINE | ID: covidwho-1469423

ABSTRACT

BACKGROUND AND AIMS: The existing evidence has indicated that hyperthermia ablation (HA) and HA combined with transarterial chemoembolization (HATACE) are the optimal alternative to surgical resection for patients with hepatocellular carcinoma (HCC) in the COVID-19 crisis. However, the evidence for decision-making is lacking in terms of comparison between HA and HATACE. Herein, a comprehensive evaluation was performed to compare the efficacy and safety of HATACE with monotherapy. MATERIALS AND METHODS: Worldwide studies were collected to evaluate the HATACE regimen for HCC due to the practical need for global extrapolation of applicative population. Meta-analyses were performed using the RevMan 5.3 software (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, Denmark). RESULTS: Thirty-six studies involving a large sample of 5036 patients were included finally. Compared with HA alone, HATACE produced the advantage of 5-year overall survival (OS) rate (OR:1.90; 95%CI:1.46,2.46; p < 0.05) without increasing toxicity (p ≥ 0.05). Compared with TACE alone, HATACE was associated with superior 5-year OS rate (OR:3.54; 95%CI:1.96,6.37; p < 0.05) and significantly reduced the incidences of severe liver damage (OR:0.32; 95%CI:0.11,0.96; p < 0.05) and ascites (OR:0.42; 95%CI:0.20,0.88; p < 0.05). Subgroup analysis results of small (≤3 cm) HCC revealed that there were no significant differences between the HATACE group and HA monotherapy group in regard to the OS rates (p ≥ 0.05). CONCLUSIONS: Compared with TACE alone, HATACE was more effective and safe for HCC. Compared with HA alone, HATACE was more effective for non-small-sized (>3 cm) HCC with comparable safety. However, the survival benefit of adjuvant TACE in HATACE regimen was not found for the patients with small (≤3 cm) HCC.


Subject(s)
Carcinoma, Hepatocellular/therapy , Chemoembolization, Therapeutic/methods , Hyperthermia, Induced/methods , Liver Neoplasms/therapy , COVID-19 , Carcinoma, Hepatocellular/mortality , Combined Modality Therapy , Humans , Liver Neoplasms/mortality , Randomized Controlled Trials as Topic , Treatment Outcome
11.
China CDC Wkly ; 2(25): 453-457, 2020 Jun 19.
Article in English | MEDLINE | ID: covidwho-1449640

ABSTRACT

WHAT IS ALREADY KNOWN ON THIS TOPIC?: A novel human coronavirus, known as SARS-CoV-2 or 2019-nCoV, is the causative agent of the coronavirus disease 2019 (COVID-19). We have released the primers and probes of real-time reverse transcription polymerase chain reaction (rRT-PCR) assays for the laboratory detection of COVID-19 infection. WHAT IS ADDED BY THIS REPORT?: Here we provide detailed technical data and evaluate the performance of three novel rRT-PCR assays targeting the ORF1ab, N, and E genes for detection of COVID-19 infection. The application of rRT-PCR assays among four types of specimens (alveolar lavage, sputum, throat swabs, and stool) from patients with COVID-19 indicated that the mean viral loads detected in sputum were higher than other specimens. WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE?: These rRT-PCR assays reported here could be used for laboratory diagnosis of COVID-19 infection with high sensitivity, specificity, and applicability. Sputum rather than throat swabs and stool should be a priority for specimen collection for laboratory detection of COVID-19.

12.
mBio ; 12(5): e0222021, 2021 10 26.
Article in English | MEDLINE | ID: covidwho-1440803

ABSTRACT

Coronavirus disease 2019 (COVID-19) has caused huge deaths and economic losses worldwide in the current pandemic. The main protease (Mpro) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is thought to be an ideal drug target for treating COVID-19. Leupeptin, a broad-spectrum covalent inhibitor of serine, cysteine, and threonine proteases, showed inhibitory activity against Mpro, with a 50% inhibitory concentration (IC50) value of 127.2 µM in vitro in our study here. In addition, leupeptin can also inhibit SARS-CoV-2 in Vero cells, with 50% effective concentration (EC50) values of 42.34 µM. More importantly, various strains of streptomyces that have a broad symbiotic relationship with medicinal plants can produce leupeptin and leupeptin analogs to regulate autogenous proteases. Fingerprinting and structure elucidation using high-performance liquid chromatography (HPLC) and high-resolution mass spectrometry (HRMS), respectively, further proved that the Qing-Fei-Pai-Du (QFPD) decoction, a traditional Chinese medicine (TCM) formula for the effective treatment of COVID-19 during the period of the Wuhan outbreak, contains leupeptin. All these results indicate that leupeptin at least contributes to the antiviral activity of the QFPD decoction against SARS-CoV-2. This also reminds us to pay attention to the microbiomes in TCM herbs as streptomyces in the soil might produce leupeptin that will later infiltrate the medicinal plant. We propose that plants, microbiome, and microbial metabolites form an ecosystem for the effective components of TCM herbs. IMPORTANCE A TCM formula has played an important role in the treatment of COVID-19 in China. However, the mechanism of TCM action is still unclear. In this study, we identified leupeptin, a metabolite produced by plant-symbiotic actinomyces (PSA), which showed antiviral activity in both cell culture and enzyme assays. Moreover, leupeptin found in the QFPD decoction was confirmed by both HPLC fingerprinting and HRMS. These results suggest that leupeptin likely contributes to the antiviral activity of the QFPD decoction against SARS-CoV-2. This result gives us important insight into further studies of the PSA metabolite and medicinal plant ecosystem for future TCM modernization research.


Subject(s)
COVID-19/drug therapy , Leupeptins/therapeutic use , Medicine, Chinese Traditional/methods , Animals , Chlorocebus aethiops , Ecosystem , Humans , SARS-CoV-2/drug effects , SARS-CoV-2/pathogenicity , Vero Cells
13.
Proc Natl Acad Sci U S A ; 118(39)2021 09 28.
Article in English | MEDLINE | ID: covidwho-1428995

ABSTRACT

Bats are responsible for the zoonotic transmission of several major viral diseases, including those leading to the 2003 SARS outbreak and likely the ongoing COVID-19 pandemic. While comparative genomics studies have revealed characteristic adaptations of the bat innate immune system, functional genomic studies are urgently needed to provide a foundation for the molecular dissection of the viral tolerance in bats. Here we report the establishment of genome-wide RNA interference (RNAi) and CRISPR libraries for the screening of the model megabat, Pteropus alecto. We used the complementary RNAi and CRISPR libraries to interrogate P. alecto cells for infection with two different viruses: mumps virus and influenza A virus, respectively. Independent screening results converged on the endocytosis pathway and the protein secretory pathway as required for both viral infections. Additionally, we revealed a general dependence of the C1-tetrahydrofolate synthase gene, MTHFD1, for viral replication in bat cells and human cells. The MTHFD1 inhibitor, carolacton, potently blocked replication of several RNA viruses, including SARS-CoV-2. We also discovered that bats have lower expression levels of MTHFD1 than humans. Our studies provide a resource for systematic inquiry into the genetic underpinnings of bat biology and a potential target for developing broad-spectrum antiviral therapy.


Subject(s)
Aminohydrolases/genetics , COVID-19/genetics , Formate-Tetrahydrofolate Ligase/genetics , Methylenetetrahydrofolate Dehydrogenase (NADP)/genetics , Multienzyme Complexes/genetics , Pandemics , Aminohydrolases/antagonists & inhibitors , Animals , Antiviral Agents/therapeutic use , COVID-19/drug therapy , COVID-19/virology , Cell Line , Chiroptera/genetics , Chiroptera/virology , Formate-Tetrahydrofolate Ligase/antagonists & inhibitors , Humans , Methylenetetrahydrofolate Dehydrogenase (NADP)/antagonists & inhibitors , Minor Histocompatibility Antigens , Multienzyme Complexes/antagonists & inhibitors , RNA Viruses/genetics , SARS-CoV-2/pathogenicity , Virus Replication/genetics
15.
Front Genet ; 12: 728960, 2021.
Article in English | MEDLINE | ID: covidwho-1417081

ABSTRACT

Despite that several therapeutic agents have exhibited promising prevention or treatment on Coronavirus disease-2019 (COVID-19), there is no specific drug discovered for this pandemic. Targeting virus-host interactome provides a more effective strategy for antivirus drug discovery compared with targeting virus proteins. In this study, we developed a network-based infrastructure to prioritize promising drug candidates from natural products and approved drugs via targeting host proteins of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). We firstly measured the network distances between drug targets and COVID-19 disease module utilizing the network proximity approach, and identified 229 approved drugs as well as 432 natural products had significant associations with SARS-CoV-2. After searching for previous literature evidence, we found that 60.7% (139/229) of approved drugs and 39.6% (171/432) of natural products were confirmed with antivirus or anti-inflammation. We further integrated our network-based predictions and validated anti-SARS-CoV-2 activities of some compounds. Four drug candidates, including hesperidin, isorhapontigenin, salmeterol, and gallocatechin-7-gallate, have exhibited activity on SARS-COV-2 virus-infected Vero cells. Finally, we showcased the mechanism of actions of isorhapontigenin and salmeterol via network analysis. Overall, this study offers forceful approaches for in silico identification of drug candidates on COVID-19, which may facilitate the discovery of antiviral drug therapies.

16.
Signal Transduct Target Ther ; 6(1): 343, 2021 09 16.
Article in English | MEDLINE | ID: covidwho-1415924

ABSTRACT

SARS-CoV-2 recognizes, via its spike receptor-binding domain (S-RBD), human angiotensin-converting enzyme 2 (ACE2) to initiate infection. Ecto-domain protein of ACE2 can therefore function as a decoy. Here we show that mutations of S19W, T27W, and N330Y in ACE2 could individually enhance SARS-CoV-2 S-RBD binding. Y330 could be synergistically combined with either W19 or W27, whereas W19 and W27 are mutually unbeneficial. The structures of SARS-CoV-2 S-RBD bound to the ACE2 mutants reveal that the enhanced binding is mainly contributed by the van der Waals interactions mediated by the aromatic side-chains from W19, W27, and Y330. While Y330 and W19/W27 are distantly located and devoid of any steric interference, W19 and W27 are shown to orient their side-chains toward each other and to cause steric conflicts, explaining their incompatibility. Finally, using pseudotyped SARS-CoV-2 viruses, we demonstrate that these residue substitutions are associated with dramatically improved entry-inhibition efficacy toward both wild-type and antibody-resistant viruses. Taken together, our biochemical and structural data have delineated the basis for the elevated S-RBD binding associated with S19W, T27W, and N330Y mutations in ACE2, paving the way for potential application of these mutants in clinical treatment of COVID-19.


Subject(s)
Angiotensin-Converting Enzyme 2/chemistry , COVID-19 , Molecular Dynamics Simulation , Mutation, Missense , SARS-CoV-2/chemistry , Amino Acid Substitution , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Antibodies, Viral/chemistry , Antibodies, Viral/metabolism , Humans , SARS-CoV-2/genetics , SARS-CoV-2/metabolism
17.
International Journal of Infectious Diseases ; 94:49-52, 2020.
Article in English | CAB Abstracts | ID: covidwho-1409644

ABSTRACT

Objective: To investigate the diagnostic value of serological testing and dynamic variance of serum antibody in coronavirus disease 2019 (COVID-19).

18.
Nucleic Acids Res ; 49(9): 5382-5392, 2021 05 21.
Article in English | MEDLINE | ID: covidwho-1387965

ABSTRACT

The emergence of SARS-CoV-2 infection has posed unprecedented threat to global public health. The virus-encoded non-structural protein 14 (nsp14) is a bi-functional enzyme consisting of an exoribonuclease (ExoN) domain and a methyltransferase (MTase) domain and plays a pivotal role in viral replication. Here, we report the structure of SARS-CoV-2 nsp14-ExoN domain bound to its co-factor nsp10 and show that, compared to the SARS-CoV nsp10/nsp14-full-length complex, SARS-CoV-2 nsp14-ExoN retains an integral exoribonuclease fold and preserves an active configuration in the catalytic center. Analysis of the nsp10/nsp14-ExoN interface reveals a footprint in nsp10 extensively overlapping with that observed in the nsp10/nsp16 structure. A marked difference in the co-factor when engaging nsp14 and nsp16 lies in helix-α1', which is further experimentally ascertained to be involved in nsp14-binding but not in nsp16-engagement. Finally, we also show that nsp10/nsp14-ExoN is enzymatically active despite the absence of nsp14-MTase domain. These data demonstrate that SARS-CoV-2 nsp10/nsp14-ExoN functions as an exoribonuclease with both structural and functional integrity.


Subject(s)
Biocatalysis , Exoribonucleases/chemistry , Exoribonucleases/metabolism , SARS-CoV-2/chemistry , SARS-CoV-2/enzymology , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/metabolism , Viral Regulatory and Accessory Proteins/chemistry , Viral Regulatory and Accessory Proteins/metabolism , Binding Sites , Crystallography, X-Ray , Exoribonucleases/genetics , Guanine , Methyltransferases/chemistry , Methyltransferases/deficiency , Methyltransferases/genetics , Methyltransferases/metabolism , Models, Molecular , Protein Domains/genetics , SARS-CoV-2/genetics , Viral Nonstructural Proteins/genetics , Viral Regulatory and Accessory Proteins/genetics
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