Connections between biomechanics and higher infectivity: a tale of the D614G mutation in the SARS-CoV-2 spike protein.
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ABSTRACT:
SUBMITTER: Mittal A
PROVIDER: S-EPMC7797704 | biostudies-literature | 2021 Jan
REPOSITORIES: biostudies-literature
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Connections between biomechanics and higher infectivity: a tale of the D614G mutation in the SARS-CoV-2 spike protein.
Mittal Anshumali A Verma Vikash V
Signal transduction and targeted therapy 20210111 1
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Project description:SARS-CoV-2 variants with spike (S)-protein D614G mutations now predominate globally. We therefore compare the properties of the mutated S protein (SG614) with the original (SD614). We report here pseudoviruses carrying SG614 enter ACE2-expressing cells more efficiently than those with SD614. This increased entry correlates with less S1-domain shedding and higher S-protein incorporation into the virion. Similar results are obtained with virus-like particles produced with SARS-CoV-2 M, N, E, and S proteins. However, D614G does not alter S-protein binding to ACE2 or neutralization sensitivity of pseudoviruses. Thus, D614G may increase infectivity by assembling more functional S protein into the virion.
| S-EPMC7693302 | biostudies-literature
Project description:ObjectiveThe coronavirus disease 2019 (COVID-19) pandemic has caused an exponential rise in death rates and hospitalizations. The aim of this study was to characterize the D614G substitution in the severe acute respiratory syndome coronavirus 2 (SARS-CoV-2) spike glycoprotein (S protein), which may affect viral infectivity.MethodsThe effect of D614G substitution on the structure and thermodynamic stability of the S protein was analyzed with use of DynaMut and SCooP. HDOCK and PRODIGY were used to model furin protease binding to the S protein RRAR cleavage site and calculate binding affinities. Molecular dynamics simulations were used to predict the S protein apo structure, the S protein-furin complex structure, and the free binding energy of the complex.ResultsThe D614G substitution in the G clade of SARS-CoV-2 strains introduced structural mobility and decreased the thermal stability of the S protein (??G?=?-0.086?kcal mol-1). The substitution resulted in stronger binding affinity (Kd?=?1.6?×?10-8) for furin, which may enhance S protein cleavage. The results were corroborated by molecular dynamics simulations demonstrating higher binding energy of furin and the S protein D614G mutant (-61.9?kcal?mol-1 compared with -56.78?kcal?mol-1 for wild-type S protein).ConclusionsThe D614G substitution in the G clade induced flexibility of the S protein, resulting in increased furin binding, which may enhance S protein cleavage and infiltration of host cells. Therefore, the SARS-CoV-2 D614G substitution may result in a more virulent strain.
| S-EPMC7567667 | 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: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: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: Not available
| EMPIAR-10891 | biostudies-other
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:A single mutation from aspartate to glycine at position 614 has dominated all circulating variants of the severe acute respiratory syndrome coronavirus 2. D614G mutation induces structural changes in the spike (S) protein that strengthen the virus infectivity. Here, we use molecular dynamics simulations to dissect the effects of mutation and 630-loop rigidification on S-protein structure. The introduction of the mutation orders the 630-loop structure and thereby induces global structural changes toward the cryoelectron microscopy structure of the D614G S-protein. The ordered 630-loop weakens local interactions between the 614th residue and others in contrast to disordered structures in the wild-type protein. The mutation allosterically alters global interactions between receptor-binding domains, forming an asymmetric and mobile down conformation and facilitating transitions toward up conformation. The loss of salt bridge between D614 and K854 upon the mutation generally stabilizes S-protein protomer, including the fusion peptide proximal region that mediates membrane fusion. Understanding the molecular basis of D614G mutation is crucial as it dominates in all variants of concern, including Delta and Omicron.
| S-EPMC9671695 | 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
Project description:The spike D614G mutation increases SARS-CoV-2 infectivity, viral load, and transmission but the molecular mechanism underlying these effects remains unclear. We report here that spike is trafficked to lysosomes and that the D614G mutation enhances the lysosomal sorting of spike and the lysosomal accumulation of spike-positive punctae in SARS-CoV-2-infected cells. Spike trafficking to lysosomes is an endocytosis-independent, V-ATPase-dependent process, and spike-containing lysosomes drive lysosome clustering but display poor lysotracker labeling and reduced uptake of endocytosed materials. These results are consistent with a lysosomal pathway of coronavirus biogenesis and raise the possibility that a common mechanism may underly the D614G mutation's effects on spike protein trafficking in infected cells and the accelerated entry of SARS-CoV-2 into uninfected cells.
| S-EPMC7743070 | biostudies-literature