SARS-CoV-2 spike-protein D614G mutation increases virion spike density and infectivity.
Ontology highlight
ABSTRACT:
SUBMITTER: Zhang L
PROVIDER: S-EPMC7693302 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:SARS coronavirus 2 (SARS-CoV-2) isolates encoding a D614G mutation in the viral spike (S) protein predominate over time in locales where it is found, implying that this change enhances viral transmission. We therefore compared the functional properties of the S proteins with aspartic acid (S D614 ) and glycine (S G614 ) at residue 614. We observed that retroviruses pseudotyped with S G614 infected ACE2-expressing cells markedly more efficiently than those with S D614 . This greater infectivity was correlated with less S1 shedding and greater incorporation of the S protein into the pseudovirion. Similar results were obtained using the virus-like particles produced with SARS-CoV-2 M, N, E, and S proteins. However, S G614 did not bind ACE2 more efficiently than S D614 , and the pseudoviruses containing these S proteins were neutralized with comparable efficiencies by convalescent plasma. These results show S G614 is more stable than S D614 , consistent with epidemiological data suggesting that viruses with S G614 transmit more efficiently.
| S-EPMC7310631 | biostudies-literature
Project description:The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein acquired a D614G mutation early in the pandemic that confers greater infectivity and is now the globally dominant form. To determine whether D614G might also mediate neutralization escape that could compromise vaccine efficacy, sera from spike-immunized mice, nonhuman primates, and humans were evaluated for neutralization of pseudoviruses bearing either D614 or G614 spike. In all cases, the G614 pseudovirus was moderately more susceptible to neutralization. The G614 pseudovirus also was more susceptible to neutralization by receptor-binding domain (RBD) monoclonal antibodies and convalescent sera from people infected with either form of the virus. Negative stain electron microscopy revealed a higher percentage of the 1-RBD "up" conformation in the G614 spike, suggesting increased epitope exposure as a mechanism of enhanced vulnerability to neutralization. Based on these findings, the D614G mutation is not expected to be an obstacle for current vaccine development.
| S-EPMC7707640 | biostudies-literature
Project description: Not available
| EMPIAR-10891 | biostudies-other
Project description:With the COVID-19 pandemic, the evolutionary fate of SARS-CoV-2 becomes a matter of utmost concern. Mutation D614G in the spike (S) protein has become dominant, and recent evidence suggests it yields a more stable phenotype with higher transmission efficacy. We carry out a structural analysis that provides mechanistic clues on the enhanced infectivity. The D614G substitution creates a sticky packing defect in subunit S1, promoting its association with subunit S2 as a means to stabilize the structure of S1 within the S1/S2 complex. The results raise the therapeutic possibility of immunologically targeting the epitope involved in stabilizing the G614 phenotype as a means of reducing the infection efficacy of SARS-CoV-2. This therapeutic modality would not a-priori interfere directly with current efforts toward the immunological targeting of the RBD epitope; hence, it could be exploited as a complementary treatment.
| S-EPMC7433342 | biostudies-literature
Project description:The SARS-CoV2 coronavirus responsible for the current COVID19 pandemic has been reported to have a relatively low mutation rate. Nevertheless, a few prevalent variants have arisen that give the appearance of undergoing positive selection as they are becoming increasingly widespread over time. Most prominent among these is the D614G amino acid substitution in the SARS-CoV2 Spike protein, which mediates viral entry. The D614G substitution, however, is in linkage disequilibrium with the ORF1b P314L mutation where both mutations almost invariably co-occur, making functional inferences problematic. In addition, the possibility of repeated new introductions of the mutant strain does not allow one to distinguish between a founder effect and an intrinsic genetic property of the virus. Here, we synthesized and expressed the WT and D614G variant SARS-Cov2 Spike protein, and report that using a SARS-CoV2 Spike protein pseudotyped lentiviral vector we observe that the D614G variant Spike has >1/2 log10 increased infectivity in human cells expressing the human ACE2 protein as the viral receptor. The increased binding/fusion activity of the D614G Spike protein was corroborated in a cell fusion assay using Spike and ACE2 proteins expressed in different cells. These results are consistent with the possibility that the Spike D614G mutant increases the infectivity of SARS-CoV2.
| S-EPMC7386486 | biostudies-literature
Project description:The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein substitution D614G became dominant during the coronavirus disease 2019 (COVID-19) pandemic1,2. However, the effect of this variant on viral spread and vaccine efficacy remains to be defined. Here we engineered the spike D614G substitution in the USA-WA1/2020 SARS-CoV-2 strain, and found that it enhances viral replication in human lung epithelial cells and primary human airway tissues by increasing the infectivity and stability of virions. Hamsters infected with SARS-CoV-2 expressing spike(D614G) (G614 virus) produced higher infectious titres in nasal washes and the trachea, but not in the lungs, supporting clinical evidence showing that the mutation enhances viral loads in the upper respiratory tract of COVID-19 patients and may increase transmission. Sera from hamsters infected with D614 virus exhibit modestly higher neutralization titres against G614 virus than against D614 virus, suggesting that the mutation is unlikely to reduce the ability of vaccines in clinical trials to protect against COVID-19, and that therapeutic antibodies should be tested against the circulating G614 virus. Together with clinical findings, our work underscores the importance of this variant in viral spread and its implications for vaccine efficacy and antibody therapy.
| S-EPMC8158177 | biostudies-literature
Project description:The causative agent of the COVID-19 pandemic, SARS-CoV-2, is steadily mutating during continuous transmission among humans. Such mutations can occur in the spike (S) protein that binds to the ACE2 receptor and is cleaved by TMPRSS2. However, whether S mutations affect SARS-CoV-2 cell entry remains unknown. Here, we show that naturally occurring S mutations can reduce or enhance cell entry via ACE2 and TMPRSS2. A SARS-CoV-2 S-pseudotyped lentivirus exhibits substantially lower entry than that of SARS-CoV S. Among S variants, the D614G mutant shows the highest cell entry, as supported by structural and binding analyses. Nevertheless, the D614G mutation does not affect neutralization by antisera against prototypic viruses. Taken together, we conclude that the D614G mutation increases cell entry by acquiring higher affinity to ACE2 while maintaining neutralization susceptibility. Based on these findings, further worldwide surveillance is required to understand SARS-CoV-2 transmissibility among humans.
| S-EPMC7870668 | biostudies-literature
Project description:A novel variant of the SARS-CoV-2 virus carrying a point mutation in the Spike protein (D614G) has recently emerged and rapidly surpassed others in prevalence. This mutation is in linkage disequilibrium with an ORF1b protein variant (P314L), making it difficult to discern the functional significance of the Spike D614G mutation from population genetics alone. Here, we perform site-directed mutagenesis on wild-type human-codon-optimized Spike to introduce the D614G variant. Using multiple human cell lines, including human lung epithelial cells, we found that the lentiviral particles pseudotyped with Spike D614G are more effective at transducing cells than ones pseudotyped with wild-type Spike. The increased transduction with Spike D614G ranged from 1.3- to 2.4-fold in Caco-2 and Calu-3 cells expressing endogenous ACE2 and from 1.5- to 7.7-fold in A549ACE2 and Huh7.5ACE2 overexpressing ACE2. Furthermore, trans-complementation of SARS-CoV-2 virus with Spike D614G showed an increased infectivity in human cells. Although there is minimal difference in ACE2 receptor binding between the D614 and G614 Spike variants, the G614 variant is more resistant to proteolytic cleavage, suggesting a possible mechanism for the increased transduction.
| S-EPMC7891930 | biostudies-literature
Project description:A SARS-CoV-2 variant carrying the Spike protein amino acid change D614G has become the most prevalent form in the global pandemic. Dynamic tracking of variant frequencies revealed a recurrent pattern of G614 increase at multiple geographic levels: national, regional, and municipal. The shift occurred even in local epidemics where the original D614 form was well established prior to introduction of the G614 variant. The consistency of this pattern was highly statistically significant, suggesting that the G614 variant may have a fitness advantage. We found that the G614 variant grows to a higher titer as pseudotyped virions. In infected individuals, G614 is associated with lower RT-PCR cycle thresholds, suggestive of higher upper respiratory tract viral loads, but not with increased disease severity. These findings illuminate changes important for a mechanistic understanding of the virus and support continuing surveillance of Spike mutations to aid with development of immunological interventions.
| S-EPMC7332439 | biostudies-literature
Project description:SARS‐CoV‐2 has become an increasingly dangerous virus infecting 77.6 million people and resulting in over 2 million deaths in the last year. The spike glycoprotein plays an important role in the viral infection process by recognizing and binding to the ACE2 receptor in host's cells. Due to the importance of this protein, current research efforts are focused on mutations that impact viral infectivity. SARS‐CoV‐2 viruses with a spike mutation at position 614 were recently shown to be more infectious than their wild‐type ancestor. The D614G substitution eliminates a hydrogen bond with a threonine residue (T859) in an adjacent protein chain, allowing the spike protein to assume more readily an open conformation. Since the open conformation mediates attachment to the ACE2 receptor, the D614G mutant causes higher infectivity than the wild‐type spike protein. The main goal of this research was to create physical 3D printed models of the wild‐type and mutant spike proteins to visualize the molecular changes caused by the D614G mutation. Structural analyses of the wild‐type and the D614G spike mutant were performed using the Protein Data Bank files, 6vxx and 6xs6. To visualize the conformational changes caused by the D614G mutation, the protein structure alignments were performed using Pymol. A combined file containing the superimposed structures was imported into Jmol to create the scripts for model construction and 3D printing. A small protein model was built to describe the overall structure of the spike and the location of the amino acids linked to higher viral infectivity. An additional detailed model was constructed to illustrate the biochemical interactions at the mutation site. In this model, important amino acids such as Asp614, Ala647, and Thr859 are highlighted due to their role in hydrogen bonding and spike protein binding to the ACE2 receptor. A magnetic piece was created to show the effects of the aspartic acid to glycine mutation at position 614. A Jmol tutorial was designed to complement the 3D models and assess students’ learning of the structure and function of SARS‐CoV‐2 spike protein. This exercise will allow undergraduate students and faculty to visualize and better understand how single amino acid mutations can lead to changes in viral infectivity.
| S-EPMC8239501 | biostudies-literature