HomeIndia NewsIISc study shows forms of SARS-CoV2 S-protein | India News

IISc study shows forms of SARS-CoV2 S-protein | India News

BENGALURU: A research team from the Indian Institute of Science (IISc) has made a crucial breakthrough by successfully visualising different conformations or forms of the S-protein of the SARS-CoV2 — the virus causing Covid-19 — which exists in mainly two conformations: open and closed.
According to IISc, in the study, researchers detected multiple distinct intermediate conformations between fully open and closed forms. Moreover, they show that distinct states of both conformations have different binding affinities towards neutralising antibodies. “The structural insights gained from this study could aid in developing therapeutics,” IISc added.
The work led by Somnath Dutta, assistant professor at the Molecular Biophysics Unit (MBU) of IISc has been published in Structure, a peer-reviewed scientific journal.
A salient feature of SARS-CoV-2 is the presence of the spike (S) proteins on the surface of the membrane that envelopes the genetic material of the virus. They appear as the characteristic crown-like spikes on the viral surface.
And, the S-protein is significant for multiple reasons: It mediates the entry of the virus into the host cell and is also the site where neutralising antibodies produced by the host cells bind to the virus in order to inactivate it. It is therefore important to understand the detailed structure of this protein, the researchers argued.
“Most previous studies on the structure of the S protein have been carried out either at potential Hydrogen 8.0 ((pH 8.0) or pH 4.0 to pH 5.0. But the structure of S-protein at physiologically relevant conditions — at which the virus infects the host cells — remains poorly understood. Recently, Dutta’s team has made a crucial breakthrough by successfully visualised the different forms of the protein at physiological pH 7.4 and near physiological pH (pH 6.5 and pH 8.0) using a technique called single-particle cryo-electron microscopy,” according to IISc.
Pointing out that the said protein exists in mainly two conformations, “open and closed”, the institute said that the open conformation is the form which helps the protein bind to the host cell receptor, thus making way for the virus to enter the cell.
“The team observed that around 68% of the S-proteins exist in open conformation at physiological pH 7.4, but their proportion decreases when the pH is slightly higher (pH 8.0) or lower (pH 6.5). This suggests that the interaction between the S protein and receptor is more favoured at physiological pH (pH 7.4) than on either side of the biological pH scale,” IISc said.
The other authors of the study are: Ishika Pramanick, Nayanika Sengupta, Suman Mishra, Suman Pandey, Nidhi Girish and Alakta Das.



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