Coronaviruses evolve to recognize glycans of their host species

Date:
April 13, 2022
Source:
American Chemical Society
Summary:
Researchers have characterized the binding of proteins from several
animal and human coronaviruses to glycans called sialic acids,
revealing host-specific patterns of binding.



FULL STORY ==========================================================================
When coronaviruses jump species -- as SARS-CoV-2 is thought to have
done from bats or pangolins to humans -- they must quickly adapt to
their new host. For example, they must evolve to recognize the unique
sugar molecules, or glycans, that decorate proteins on the host cell's
surface. Now, researchers reporting in ACS Infectious Diseaseshave characterized the binding of proteins from several animal and human coronaviruses to glycans called sialic acids, revealing host-specific
patterns of binding.


========================================================================== Sialic acids are negatively charged, nine-carbon sugar molecules that cap
the ends of sugar chains attached to proteins on the cell's surface. In vertebrates, N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic
acid (Neu5Gc) are the most common forms of sialic acids. Enzymes can add
acetyl groups to various places on these molecules, making more than 10 molecular variants of each. Geert-Jan Boons and colleagues wanted to characterize the repertoire of sialic acid variants recognized by two
viral proteins, the receptor binding domain (RBD) of the spike protein and hemagglutinin-esterase (HE), from several animal and human coronaviruses.

The researchers used chemical and enzymatic treatments to prepare a
complete library of acetylated Neu5Ac and Neu5Gc variants. They printed
these molecules onto a glass slide to produce a microarray. Next, the
team used a fluorescent antibody detection system to determine whether
the RBD and HE from bovine, rabbit, equine and canine coronaviruses
bound to specific spots on the microarray. Because human coronavirus
HEs have lost the ability to bind sialic acid-containing carbohydrates,
they tested only the RBD from the human coronavirus OC43, which typically causes mild cold-like symptoms. The researchers found that HE from each
species bound less to Neu5Gc than Neu5Ac variants. The RBDs from each
species bound to both Neu5Ac and Neu5Gc variants, but with different
patterns. The results revealed that coronaviruses have fine- tuned their specificities to adapt to the sialic acid variants of their host.

This information could provide important insights into the factors
driving cross-species transmission, helping scientists to predict and
prevent future outbreaks, the researchers say.

The authors acknowledge funding and support from the Netherlands
Organization for Scientific Research, the Human Frontier Science Program Organization, the Council for Chemical Sciences of the Netherlands
Organization for Scientific Research and the China Scholarship Council.


========================================================================== Story Source: Materials provided by American_Chemical_Society. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Zeshi Li, Lin Liu, Luca Unione, Yifei Lang, Raoul J. de Groot,
Geert-Jan
Boons. Synthetic O-Acetyl-N-glycolylneuraminic Acid
Oligosaccharides Reveal Host-Associated Binding Patterns of
Coronaviral Glycoproteins. ACS Infectious Diseases, 2022; DOI:
10.1021/acsinfecdis.2c00046 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220413090938.htm

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