Ponente
Descripción
SARS-CoV-2 receptor binding domain (RBD) interacts with the angiotensin converting enzyme (ACE2) mediating viral entry to the human cells. The RBD is the target of neutralizing antibodies raised during infection or after vaccination. Since its discovery in 2019, the virus has undergone an accelerated evolution. As a consequence, new variants carrying mutations in the RBD that enhance binding to hACE2 or enable escape from neutralizing antibodies, have become dominant worldwide. This highlights the need to understand the molecular bases of RBD-hACE2 interaction and to predict mutations that might confer evolutionary advantages to the virus. Phage display technology is a powerful method based on the cloning of the gene of interest fused to the gene of a phage coat protein. Combining this platform with mutagenesis methods allows to create collections of mutated proteins to determine the contribution of a given residue to a protein-protein interaction. In this work, we displayed biologically active SARS-CoV-2 RBD on phages. The heterologous protein was antigenically equivalent to natural RBD as it was recognized by specific monoclonal antibodies and convalescent patients’ sera. Variants of concern RBDs displayed on phages exhibited relative reactivities against hACE2 comparable to those of their equivalents produced in mammalian cells, indicating that the effect of mutations on RBD biological activity can be reproduced in this system. Mutational scanning of this protein allowed us to identify key aminoacids and essential molecular patterns for the interaction with the human receptor, as well as sites where mutations tend to affect the inhibitory capacity of vaccine-induced polyclonal antibodies.
