IISc-CSIR Research to inactivate SARS-CoV-2

July 15, 2022

Researchers from Indian Institute of Science (IISc) recently conducted an experiment to inactivate the SARS-CoV-2 virus, in collaboration with the CSIR-Institute of Microbial Technology.

Key Facts

Researchers found the design of a new class of synthetic peptides. The peptides can block the entry of SARS-CoV-2 virus entry into cells, besides grouping the virus particles together. This way, the ability of virus to infect also reduces.
The need of this research got triggered due to rapid emergence of new strains of SARS-CoV-2 virus. It has decreased the protection offered by COVID-19 vaccines.

Protein-Protein interaction and new peptide

Protein-protein interaction is similar to that of a lock and a key. This interaction can be obstructed by synthetic peptide that similar to and competes with, stops the ‘key’ from binding to ‘lock’.
The new peptides can bind with and block the spoke protein present in the coronavirus.
This binding was characterised by cryo-electron microscopy (cryo-EM) and other such biophysical methods.
Designed peptides are hairpin-shaped and helical. Each of the peptides is capable to pair up with another peptide, forming a dimer.
Each dimeric ‘bundle’ provides two ‘faces’ for interacting with two target molecules. The two faces would bind with two different target proteins and lock all four in a complex. This way, it will block the targets.

S Protein Trimer

S protein is a trimer. It is a complex of three similar polypeptides. Every polypeptide comprises of a “Receptor Binding Domain (RBD)”, which sticks with the ACE2 receptor on surface of host cell. This interaction provides for viral entry into the cell. SIH-5 peptide was developed for blocking the RBD binding to human ACE2.

SIH-5 and s protein cross linking

When SIH-5 peptide come in contact with an S protein, one of its faces stick tightly with the three RBDs on S protein trimer, while the other face stick to the RBD from different S protein. This cross-linking helped SIH-5 in blocking both the S proteins at the same time.

Background

The research on the peptide was supported as a part of “COVID-19 IRPHA call” of SERB Science and Engineering Research Board (SERB), which is a statutory body of the Department of Science and Technology (DST).

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