Mutations in SARS-CoV-2 Variants Modulate the Microscopic Dynamics of Neutralizing Antibodies

Monoclonal antibodies have emerged as viable treatment for the COVID-19 disease caused by the SARS-CoV-2 virus. But the new viral variants can reduce the efficacy of the currently available antibodies, as well as diminish the vaccine induced immunity. Here, we demonstrate how the microscopic dynamics of the SARS-CoV-2 neutralizing monoclonal antibodies, can be modulated by the mutations present in the spike proteins of the variants currently circulating in the world population. We show that the dynamical perturbation in the antibody structure can be diverse, depending both on the nature of the antibody and on the location of the mutation. The correlated motion between the antibody and the receptor binding domain (RBD) can also be changed, altering the binding affinity. By constructing a protein graph connectivity network, we could delineate the mutant induced modifications in the allosteric information flow pathway through the antibody, and observed the presence of both localized and long distance effects. We identified a loop consisting of residues 470-490 in the RBD which works like an anchor preventing the detachment of the antibodies, and individual mutations in that region can significantly affect the antibody binding propensity. Our study provides fundamental and atomistically detailed insight on how virus neutralization by monoclonal antibody can be impacted by the mutations in the epitope, and can potentially facilitate the rational design of monoclonal antibodies, effective against the new variants of the novel coronavirus.

Heterogeneous dynamics in the curing process of epoxy resins

Epoxy resin is indispensable for modern industry because of its excellent mechanical properties, chemical resistance, and excellent moldability. To date, various methods have been used to investigate the physical properties of the cured product and the kinetics of the curing process, but its microscopic dynamics have been insufficiently studied. In this study, the microscopic dynamics in the curing process of a catalytic epoxy resin were investigated under different temperature conditions utilizing X-ray photon correlation spectroscopy. Our results revealed that the temperature conditions greatly affected the dynamical heterogeneity and cross-linking density of the cured materials. An overview of the microscopic mechanism of the curing process was clearly presented through comparison with the measurement results of other methods, such as 1H-pulse nuclear magnetic resonance spectroscopy. The quantification of such heterogeneous dynamics is particularly useful for optimizing the curing conditions of various materials to improve their physical properties.