Cases Spiking

First reported last November in South Africa, the Omicron variant of SARS-CoV-2, the virus responsible for COVID-19, has since rapidly spread around the world. Key to understanding Omicron’s success is the spike protein, which allows SARS-CoV-2 to penetrate human cells by latching onto a cell surface protein, angiotensin-converting enzyme 2 (ACE2). Compared to the original strain of SARS-CoV-2, Omicron’s spike protein displays 37 mutations, including 15 in its receptor-binding domain, the section that connects with ACE2. Cryogenic electron microscopy reveals how these changes affect the spike protein’s structure (pictured, in purple), and its interactions with ACE2 (in turquoise). Despite its many changes, Omicron’s spike protein strongly binds ACE2, with a similar efficiency to the spike protein of the Delta variant. Conversely, antibodies from patients both vaccinated or recovered from infections with other variants were less successful in neutralising Omicron’s spike protein, suggesting its mutations help it evade the immune response.

Written by Emmanuelle Briolat

Emmanuelle Briolat

Writer

A researcher specialising in visual signals in Lepidoptera, camouflage and the effects of light pollution, Emmanuelle’s writing covers a range of topics, from biomedical research to children’s books about moth defences.

Website

• Image from work by Dhiraj Mannar, James W. Saville and Xing Zhu, and colleagues, UBC Faculty of Medicine
• Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
• Image copyright held by the original authors
• Research published in Science, January 2022