Abstract
SARS-CoV-2 infection is controlled by the opening of the spike protein receptor binding domain (RBD), which transitions from a glycan-shielded ‘down’ to an exposed ‘up’ state to bind the human angiotensin-converting enzyme 2 receptor and infect cells. While snapshots of the ‘up’ and ‘down’ states have been obtained by cryo-electron microscopy and cryo-electron tomagraphy, details of the RBD-opening transition evade experimental characterization. Here over 130 µs of weighted ensemble simulations of the fully glycosylated spike ectodomain allow us to characterize more than 300 continuous, kinetically unbiased RBD-opening pathways. Together with ManifoldEM analysis of cryo-electron microscopy data and biolayer interferometry experiments, we reveal a gating role for the N-glycan at position N343, which facilitates RBD opening. Residues D405, R408 and D427 also participate. The atomic-level characterization of the glycosylated spike activation mechanism provided herein represents a landmark study for ensemble pathway simulations and offers a foundation for understanding the fundamental mechanisms of SARS-CoV-2 viral entry and infection.
【초록키워드】 SARS-COV-2 infection, Infection, Cryo-electron microscopy, Receptor binding domain, RBD, pathway, receptor, mechanism, Analysis, Pathways, Activation, human Angiotensin-converting enzyme, ectodomain, infect cells, while, offer, SARS-CoV-2 viral, provided, facilitate, the spike protein, evade, experiments, glycosylated, R408, 【제목키워드】 Spike protein, Control, the SARS-CoV-2,