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BREAKING NEWS
Source: COVID-19 Latest  Jul 26, 2020  3 years, 8 months, 3 weeks, 1 day, 6 hours, 43 minutes ago

BREAKING! COVID-19 Latest: Study Reveals That SARS-CoV-2 Spike Protein Has Shape Shifting Ability To Evade Immune Attacks And To Ensure Its Survival

BREAKING! COVID-19 Latest: Study Reveals That SARS-CoV-2 Spike Protein Has Shape Shifting Ability To Evade Immune Attacks And To Ensure Its Survival
Source: COVID-19 Latest  Jul 26, 2020  3 years, 8 months, 3 weeks, 1 day, 6 hours, 43 minutes ago
COVID-19-Latest: A study led by Boston Children's Hospital has found that the SARS-CoV-2 coronavirus spike proteins bind to human cells via the ACE2 receptor and then dramatically change shape, jack-knifing to fuse the cell membrane with the coronavirus's outer membrane and opening the door to coronavirus infection.
 
The study for the first time freeze-frames the spike protein in its "before" and "after" shapes.
 
The research findings published in the journal Science also captured some surprise features of the spike protein, which is also the main protein targeted by our antibodies and the protein used in most vaccines now in human testing. https://science.sciencemag.org/content/early/2020/07/20/science.abd4251


The two alternate shapes of the SARS-CoV-2 spike protein, before and after fusion of the viral and cell membranes.
Credit: Image created with Molecular Maya by Jonathan Khao, PhD and Gaël McGill, PhD, Digizyme Inc.


The researchers, led by Dr Bing Chen, Ph.D., believe the unexpected features may help SARS-CoV-2 hide from the immune system and survive longer in the environment. This new findings may also have implications for vaccine and therapeutic development.
 
Utilizing the technique of cryogenic electron microscopy, Dr Chen and colleagues in Boston Children's Division of Molecular Medicine established the structure of the spike protein, both before and after fusion of the virus and cell membranes. In the "after," post-fusion state, the protein assumes a rigid hairpin shape folded in on itself, they showed.
 
Interestingly, they also found that the spike protein sometimes goes from its original "before" shape into the "after" form prematurely, without the virus binding to the ACE2 receptor.
 
Dr Chen told Thailand Medical News, "We propose that there are two routes for the conformational changes. One is ACE2 dependent, and allows the virus to enter a host cell. The second is ACE2 independent."
 
It has been found that as a result of the spontaneous shape change, coronavirus particles often bear both forms of the spike protein, with the rigid "after" form protruding slightly more from the virus surface.
 
Dr Chen suggests that being able to assume this alternate shape even without binding to a cell may help keep SARS-CoV-2 viable in the environment, preventing it from breaking down when it lands on a surface for example. That could explain why the virus appears to remain viable on various surfaces for hours to days.

An artistic rendering of how SARS-CoV-2 fuses its membrane with the host membrane, based on the spike protein
structures reported in Science together with other data. Credit: Image created with Molecular Maya by Jonathan Khao,
PhD and Gaël McGill, PhD, Digizyme Inc.


Dr Chen added, "Most viruses don't survive long outside the host. We think the rigid structure of these post-fusion spikes protects the virus."
 
The study team speculates that having some spikes assume the post-fusion form prematurely may also protect SARS-CoV-2 from our immune system, inducing antibodies that are non-neutralizing and ineffective in containing the virus. In effect, the post-fusion spikes may act as decoys that distract the