While the world races to develop a vaccine to counter the scourge of Covid-19, a faculty member at the University of Hyderabad (UoH) has made a crucial discovery that can help in the design of antibodies capable of combating the virus.
Professor Lalita Guruprasad has identified the defining features that distinguish the coronavirus mutations possessing the ability to infect human beings.
A SARS coronavirus protein named Spike forms a crown-like appearance “Corona” that specifically binds to human angiotensin converting enzyme-2 (ACE-2) receptor. A crucial question addressed is what changes might have occurred in SARS coronavirus genomes and the spike proteins during evolution that made the virus capable of causing human infection?
Professor Guruprasad at the university”s School of Chemistry, arrived at her findings after analysing complete genomes and spike protein sequences of several SARS coronaviruses from bat, civet, human and human SARS coronavirus-2.
Her study revealed that “three sequence regions and a disulphide bridge are present only in SARS coronavirus spike proteins that bind ACE-2 receptor, whereas, these sequences are absent in bat SARS coronaviruses that are incapable of causing human infection”.
The findings could help in developing vaccines that are more efficient.
“Instead of being very vague, we”re able to precisely pinpoint the motifs or sequence regions in the proteins and say that these protein regions in the spike are required for interaction with ace 2. So if you”re able to design antibodies only on the basis of those regions and not any other parts, then there”ll be greater probability of a better vaccine because we know that it is not any region but these particular regions that are responsible for the interaction,” said Guruprasad.
The present Covid-19 disease caused by Severe Acute Respiratory Syndrome (SARS) coronavirus-2 with its epicentre, reported from Wuhan, China during December 2019, has rapidly become a pandemic resulting in an alarming number of infections and deaths worldwide. It is known that bats are natural reservoirs of SARS coronaviruses, which constantly gets mutated in them and jumps across species, thereby animals such as civets and pangolins acquire the virus. Further mutations of the virus and human contact with these host animals would result in human infection leading to the severe respiratory disease.
Mutations of a more transmissible form of SARS coronavirus-2 subsequently reported by the Los Alamos National Laboratory, US is associated with one of the sequence regions identified by the University of Hyderabad, India. The sequence motifs that are specific to human SARS coronavirus-2 that interact with ACE-2 can be exploited as potential candidates for antibody design.
Her study also cautions that some bat SARS coronavirus genomes are still evolving and may eventually acquire the capabilities to infect humans and pose a potential threat in future.