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Structural changes identified in COVID alpha and beta strains – suggesting the need to improve complementary vaccines

SARS-CoV-2 mutation, variant, needle surface subject to static electricity.

A mutation in the SARS-CoV-2 variant causes a change in electrostatic potential. Here, the positively charged area is shown in blue and the negatively charged area is red. in the beta variant The receptor binding domain (RBD) and the N termination domain (NTD) have changed dramatically. This affects the ability of antibodies to capture and neutralize the virus. Credits: Bing Chen, PhD, Boston Children’s Hospital.

Alteration of protein ‘spike’ explains faster alpha diffusion and how beta variants evade immune responses. Indicates the need for enhanced vaccine stimulation.

The new SARS-CoV-2 strain is spreading rapidly. And there are fears that the current COVID-19 vaccine will not protect it. The latest in a series of structural studies of the protein “needle” of the SARS-CoV-2 variant, led by Bing Chen, PhD at Boston Children’s Hospital, revealed a novel property of alpha. (formerly UK) and Beta (formerly South Africa) ) versions. Note that current vaccines may be less effective compared to beta variants.

The spike protein on the surface of SARS CoV-2 is what allows the virus to attach to and enter our cells. And all current vaccines will be against them. The new study is published in science On June 24, 2021, scanning electron microscopy (cryo-EM) was used to compare the original viral spike protein with the alpha and beta variants.

Structural findings indicate mutations in beta variants (also known as B.1.351) changes the shape of the spike surface in some places. As a result, the neutralizing antibodies generated by the current vaccine cannot bind to the beta virus. This may help it evade the immune system, even if people are vaccinated.

“Mutations make antibodies activated by current vaccines less effective,” said Chen, division of Molecular Medicine at Boston Children’s. “The beta variant is quite resistant to current vaccines. And we think that the new sequencing advocates will be helpful in preventing this variant.”

However, the study also found that mutations in the beta variant made the block less effective at binding to ACE2, indicating that the variant was less infectious than the alpha variant.

Confidence in Alpha Variables Additional variables are being studied.

For the alpha variant (B.1.1.7), the study confirmed that the genetic variation in the spike However, tests indicate that existing vaccine-activated antibodies can also neutralize this variant.

As a growing threat, SARS-CoV-2 must do three things, researchers say: It’s easier to spread. Bypass the immune system in people who have been vaccinated or who have been exposed to COVID-19 and cause more severe disease. Fortunately, not all alpha and beta variants meet these criteria.

“Our data suggest that the most problematic combination of such mutations does not yet exist in the existing variants examined here,” the researchers write.

Chen’s team also plans to report the structure of other variables of concern, including the Delta version (B.1.617.2) in the near future. Those investigations are still ongoing.

Reference: “Infrastructure for increased infection and immune evasion of SARS-CoV-2 strains” by Yongfei Cai, Jun Zhang, Tianshu Xiao, Christy L. Lavine, Shaun Rawson, Hanqin Peng, Haisun Zhu, Krishna Anand, Pei Tong, Avneesh Gautam, Shen Lu, Sarah M. Sterling, Richard M. Walsh Jr., Sophia Rits-Volloch, Jianming Lu, Duane R. Wesemann, Wei Yang, Michael S. Seaman and Bing Chen, June 24. 2021, science.
doi: 10.1126/science.abi9745

Yongfei Cai, PhD, Jun Zhang, PhD, and Tianshu Xiao, PhD of Boston Children’s Hospital are the first co-authors on this article. The study was funded by Emergent Ventures, the Massachusetts Consortium on Pathogen Readiness, and the National Institutes of Health (grant AI147884, AI141002 and AI127193).

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