S. Vishnu Sharma
IIT Madras researchers are studying the high transmission rate and mortality of SARS-COV-2, the scientific name of corona virus that causes COVID-19.
The team of IIT Madras researchers made use of computational tools, the team studied its two close variants – SARS-CoV and NL63.
The team of IIT Madras researchers were led by Professor M. Michael Gromiha, Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, IIT Madras, Dr. Puneet Rawat and Dr. Sherlyn Jemimah, Research Scholars from IIT Madras.
IIT Madras researchers collaborated with Professor P.K. Ponnuswamy, Former Vice-Chancellor, University of Madras and Madurai Kamaraj University and Professor, Department of Physics, Bharathidasan University in Tiruchi, Tamil Nadu, for this study.
IIT Madras researchers study great transmission potential
IIT Madras researchers set out to understand how the spike proteins (which enables the coronavirus to penetrate human cells and cause COVID-19) of these different virus strains are interacting with the ACE2 receptors of human cells and how this interaction is affecting their transmission potential and severity of the disease.
‘SARS-CoV’ can be considered a ‘sibling’ of the subfamily beta coronavirus ‘SARS-CoV-2.’
The ‘NL63’ belongs to sub-family alpha coronavirus can be considered as a ‘cousin’ of SARS-CoV-2, say IIT Madras researchers.
SARS-CoV is more severe than SARS-CoV-2 whereas NL63 shows milder symptoms than SARS-CoV and SARS-CoV-2.
The IIT Madras researchers set out to find the reason behind the mildness and severity of disease caused by these viruses.
From the previous studies, it was realized that all three viruses gain entry to the human cell via ACE2 receptors which are present on human cells.
The finds of the study by IIT Madras researchers is published in the well-known international journal ‘Proteins: Structure, Function, Bioinformatics.’
The Research Paper can be downloaded from the following link – ‘https://onlinelibrary.wiley.com/doi/epdf/10.1002/prot.26024’
Speaking on the work done by IIT Madras researchers Professor M. Michael Gromiha said Coronaviruses are not new to humans. Coronavirus such as NL63 causes only mild symptoms, he said.
There exist some common functional aspects among NL63 and viruses such as SARS-CoV and SARS-CoV-2, both of which are relatively severe.
This brings up several questions, like, i) Have these viruses evolved from the same ancestor? ii) Why do they cause different mortality rates?, iii) What is the extent of similarity/difference(s) among these viruses? and iv) If we have immunity for mild NL63, then is it possible that we may have some degree of immunity towards the wild ones, SARS-CoV or SARS-CoV-2?
Our effort is to find answers to these questions to an extent possible by studying the interaction mechanism of these viruses with the organs of human body, he said.
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Using various computational tools, the team of IIT Madras researchers found that the interaction area between spike protein and ACE2, surrounding hydrophobicity and interaction energy play a key role in deciding the severity and transmission potential of coronaviruses.
IIT Madras researchers also found that the distant cousin NL63 has unique ACE2 binding sites compared to SARS-CoV and SARS-CoV-2.
However, some of the binding site regions are conserved and any change in these regions is evolutionarily prohibited.
Further, IIT Madras researchers found that less interaction area, surrounding hydrophobicity and interaction energy for the interface residues are the main reasons for the mild severity of NL63 coronavirus.
There had been previous outbreaks as well. In 2002, one of its members SARS-CoV played havoc and in the year 2012, MERS-another member of the same family also spread widely.
Now, SARS-CoV-2 has spread around the world causing COVID-19 and, like SARS-CoV and MERS, the SARS-CoV-2 also spreads through sneezing, coughing and via respiratory droplets but its transmission potential turned out to be high, say IIT Madras researchers.
In future, the researchers are all set to conduct a deeper analysis of the binding regions to know which kind of minimal mutations severely affect the binding of viruses – S-proteins and ACE2 protein through experimental studies.
Such a study, IIT Madras researchers said, will help find ways to reduce the gravity of the severe disease-causing coronaviruses and develop effective therapeutic interventions, which can be used across ACE2 binding corona-virus strains and potentially other viruses that may target ACE2 for infection.
The team is also working on repurposing the known drugs, which target the identified conserved regions on the viral S-protein and can help in treating coronavirus infections.