Structure and dynamics of the interaction of Delta and Omicron BA.1 SARS-CoV-2 variants with REGN10987 Fab reveal mechanism of antibody action.

Publication date: Dec 24, 2024

Study of mechanisms by which antibodies recognize different viral strains is necessary for the development of new drugs and vaccines to treat COVID-19 and other infections. Here, we report 2. 5 A cryo-EM structure of the SARS-CoV-2 Delta trimeric S-protein in complex with Fab of the recombinant analog of REGN10987 neutralizing antibody. S-protein adopts “two RBD-down and one RBD-up” conformation. Fab interacts with RBDs in both conformations, blocking the recognition of angiotensin converting enzyme-2. Three-dimensional variability analysis reveals high mobility of the RBD/Fab regions. Interaction of REGN10987 with Wuhan, Delta, Omicron BA. 1, and mutated variants of RBDs is analyzed by microscale thermophoresis, molecular dynamics simulations, and ΔG calculations with umbrella sampling and one-dimensional potential of mean force. Variability in molecular dynamics trajectories results in a large scatter of calculated ΔG values, but Boltzmann weighting provides an acceptable correlation with experiment. REGN10987 evasion of the Omicron variant is found to be due to the additive effect of the N440K and G446S mutations located at the RBD/Fab binding interface with a small effect of Q498R mutation. Our study explains the influence of known-to-date SARS-CoV-2 RBD mutations on REGN10987 recognition and highlights the importance of dynamics data beyond the static structure of the RBD/Fab complex.

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Concepts Keywords
Angiotensin ACE2 protein, human
Drugs Angiotensin-Converting Enzyme 2
Protein Angiotensin-Converting Enzyme 2
Regn10987 Antibodies, Neutralizing
Vaccines Antibodies, Neutralizing
Antibodies, Viral
Antibodies, Viral
COVID-19
Cryoelectron Microscopy
Humans
Immunoglobulin Fab Fragments
Immunoglobulin Fab Fragments
Molecular Dynamics Simulation
Mutation
Protein Binding
Protein Conformation
SARS-CoV-2
Spike Glycoprotein, Coronavirus
Spike Glycoprotein, Coronavirus
spike protein, SARS-CoV-2

Semantics

Type Source Name
disease MESH COVID-19
disease MESH infections
disease IDO host
disease MESH SD1
disease IDO infection
disease MESH emergency
disease IDO site
disease IDO protein
drug DRUGBANK Coenzyme M
drug DRUGBANK Aspartame
drug DRUGBANK Trestolone
disease MESH point mutations
drug DRUGBANK Pidolic Acid
disease MESH dissociation
disease MESH uncertainty
drug DRUGBANK L-Leucine

Original Article

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