ZhenCui, et al. https://doi.org/10.1016/j.cell.2022.01.019
Recopilado por Carlos Cabrera Lozada. Miembro Correspondiente Nacional, ANM puesto 16. ORCID: 0000-0002-3133-5183. 27/01/2022
Highlights
Omicron spike stably maintains an active conformation for receptor recognition
Improved stability of Omicron enhances attachment but compromises viral fusion
Mutations perturb the conformation of antigenic sites recognized by most antibodies
Structurally restrained regions of RBM can be targets for COVID-19 countermeasures
SUMMARY
The SARS-CoV-2 Omicron with increased fitness is spreading rapidly worldwide. Analysis of cryo-EM structures of the Spike (S) from Omicron reveals amino acid substitutions forging interactions that stably maintain an active conformation for receptor recognition. The relatively more compact domain organization confers improved stability and enhances attachment but compromises the efficiency of the viral fusion step. Alterations in local conformation, charge and hydrophobic microenvironments underpin the modulation of the epitopes such that they are not recognized by most NTD- and RBD-antibodies, facilitating viral immune escape. Structure of the Omicron S bound with human ACE2, together with the analysis of sequence conservation in ACE2 binding region of 25 sarbecovirus members as well as heatmaps of the immunogenic sites and their corresponding mutational frequencies sheds light on conserved and structurally restrained regions that can be used for the development of broad-spectrum vaccines and therapeutics.