Scientists discover a new mechanism of coronavirus infection

Spanish researchers have discovered that the Spike protein of the SARS-Cov2 virus interacts with sialic acids in human cells to promote their internalization, which represents a new mechanism of infection by SARS-CoV2, which is causing the current pandemic of COVID-19.

As soon as the pandemic began, it was determined that the entry of this virus into host cells is facilitated by the ACE2 receptor on our cells. However, this virus has a broad tropism, and is capable of infect cells that do not have this receptor on their surface. For this reason, the scientific community has not relented in its efforts to identify possible additional molecular events that help SARS-CoV-2 in its complex mechanism of infection.

One of the possibilities that was considered from the beginning is that the virus uses the sialic acids that our cells expose on their surface as anchoring elements or attraction to host cells. This actually happens in many viral infections, but it had not been experimentally demonstrated for SARS-CoV-2. Sialic acids are sugars that occupy the terminal positions of glycans (sugars) complexes found on the surface of cells.

A study, coordinated by Jesús Jiménez-Barbero, a CIBERES researcher belonging to the Juncal Garmendia group, has been published in ‘Angewandte Chemie Int’. The researchers show for the first time that the Spike protein of SARS-CoV-2 is capable of specifically recognizing the terminal sialic acid of sugars.

The results, based on a strategy of selective carbon-13 labeling in glycans and Nuclear Magnetic Resonance (NMR) experiments, provide clear and unequivocal experimental evidence of this direct interactionwhich will foreseeably have important implications in the infection process.

“These results help us understand the complex mechanism of SARS-CoV-2 infection and face new therapeutic strategies based on blocking this interaction”, says Dr. Jiménez-Barbero.