At a Glance
- Researchers designed “miniproteins” that bound tightly to the SARS-CoV-2 spike protein and prevented the virus from infecting human cells in the lab.
- More research is underway to test the most promising of the antiviral proteins.
The surface of SARS-CoV-2, the virus that causes COVID-19, is covered with spike proteins. These proteins latch onto human cells, allowing the virus to enter and infect them. The spike binds to ACE2 receptors on the cell surface. It then undergoes a structural change that allows it to fuse with the cell. Once inside, the virus can copy itself and produce more viruses.
Blocking entry of SARS-CoV-2 into human cells can prevent infection. Researchers are testing monoclonal antibody therapies that bind to the spike protein and neutralize the virus. But these antibodies, which are derived from immune system molecules, are large and not ideal for delivery through the nose. They’re also often not stable for long periods and usually require refrigeration.
Researchers led by Dr. David Baker of the University of Washington set out to design synthetic “miniproteins” that bind tightly to the coronavirus spike protein. Their study was funded in part by NIH’s National Institute of General Medical Sciences (NIGMS) and National Institute of Allergy and Infectious Diseases (NIAID). Findings appeared in Science on September 9, 2020.
The team used two strategies to create the antiviral miniproteins. First, they incorporated a segment of the ACE2 receptor into the small proteins. The researchers used a protein design tool they developed called Rosetta blueprint builder. This technology allowed them to custom build proteins and predict how they would bind to the receptor.
The second approach was to design miniproteins from scratch, which allowed for a greater range of possibilities. Using a large library of miniproteins, they identified designs that could potentially bind within