Two University of Georgia researchers are analyzing the proteins and sugars on the coronavirus in hopes of finding information to lead to vaccines and therapeutics, according to a UGA Today news release.
Rob Woods and Parastoo Azadi are scientists at UGA’s Complex Carbohydrate Research Center, where researchers study the structures and functions of complex carbohydrates to determine their role in growth and development, host-pathogen interactions and disease processes, the release said.
Their research could have implications for the development of vaccines for SARS-CoV-2, the virus that causes COVID-19.
The virus has spike proteins on its surface that latch onto human cells and force the virus in. Usually, the human immune system detects and responds to foreign proteins by recognizing amino acid sequences, Woods said in the release.
However, if a pathogen puts a sugar on the protein’s surface, the human immune system has difficulties detecting the amino acid sequences.
“One sugar can mask a whole cluster of amino acids so our antibodies can’t see them. Many viruses do this — influenza and hepatitis C, for example,” Woods said in the release.
Woods’ team’s specialty is glycosylation, the process of how complex carbohydrates called glycans attach to and shield protein surfaces.
Woods and his team model the 3D structure of the virus’s spiked proteins and the attached sugars. Woods and his team used the Cryo-EM model published by a team in China, according to the release. Later, a study indicated which sugars were likely to be on the surface and where.
The team’s model shows which areas may be exposed, allowing researchers to figure out what an effective vaccine would need to look like.
“When designing a vaccine, you want the vaccine to generate antibodies that recognize the parts of the protein that it can bind to, that the antibodies can attack,” Woods said in the release. “By seeing where the sugars are, you can make decisions about how you’re going to make a vaccine to target the areas that are exposed and not shielded by the sugars.”
According to Woods, the sugars on the proteins “move like trees in the wind,” making it harder for the immune system to find the protein’s surface.
The team worked on other viruses, including influenza, before the spread of coronavirus. The modeling Woods used for modeling previous viruses has a similar structure to modeling COVID-19, so it made for an “easy transition” for the researchers, the release said.
“After all these years of looking at carbohydrates, it really puts us in the right position at the right time, with the right knowledge base, to do this,” Woods said in the release. “It’s very exciting for me to be at a point where we can use our tools to do something so timely.”
Azadi’s previous research experience also made the transition easy, the release said. Azadi and her team take a more experimental approach in characterizing specific types of glycosylation on the virus’s spike protein.
According to the release, the type of glycosylation plays an important role in the human immune response and in designing effective vaccines.
“Understanding glycosylation at the binding site can guide the design of vaccines,” said Azadi. “Only a vaccine that can mimic the viral protein as closely as possible can elicit an optimal immune response.”