Indian scientists reveal new mutations and proteins in novel coronavirus
A study by the Indian Institute of Science (IISc) identified multiple mutations and unique proteins in isolates of SARS-CoV-2, the virus that causes COVID-19.
The recent study, published in the “Journal of Proteome Research”, also showed that the host itself produces several proteins as its body launches an immunological defense in response to the viral attack, said the IISc based in Bengaluru in a statement on Thursday.
To better understand how the virus mutates and its protein biology (proteins are made using genetic information), an IISc team led by Utpal Tatu, professor in the Department of Biochemistry, conducted a comprehensive proteogenomic investigation of a series Analyzes of SARS-CoV-2 Isolates.
The isolates or viral samples were collected from the nasal secretions of consenting COVID-19 positive individuals here.
Genomic analysis was performed using what molecular biologists like Tatu call Next Generation Sequencing (NGS), a technology that enables rapid sequencing of the entire genome.
He says sequencing the genomes of viral strains around the world is important because it keeps track of mutations that are constantly occurring.
His team’s analysis suggests that the virus is now mutating faster than before, the three Bengaluru isolates had 27 mutations in their genomes with more than 11 mutations per sample, more than the national average (8.4) and the average global (7.3).
To understand the spread and evolutionary history of the virus, the team constructed a global phylogenetic tree, or relatedness tree, of viral isolates using the sequence data.
Phylogenetic analysis revealed that isolates from Bengaluru are most closely related to that from Bangladesh.
It also showed that isolates in India have multiple origins rather than having evolved from a single ancestral variant, the statement said.
The SARS-CoV-2 genome encodes more than 25 proteins, but only a handful of those proteins have been identified so far, he said.
“The study of viral proteins provides functional information that is currently not well represented,” says Tatu.
In the proteomics analysis, his team detected 13 different proteins, most of which had not previously been identified from clinical samples.
“One such protein called Orf9b, which suppresses the host’s immune response, had been predicted, but the IISc team provided the first evidence for its expression,” he said.
“It will not be enough to know how the virus works. We have to put it in the context of the host,” Tatu says.
Therefore, in the third analysis, his team explored how our body responds to the virus by examining the host’s proteins.
They discovered up to 441 proteins unique to COVID-19 positive patients, many of which are thought to play a key role in the body’s immune response.
Proteomic analyzes were performed using a technique called high resolution mass spectrometry.
The team is optimistic about the potential of this method for large-scale testing.
Proteins can be reliable markers of infections like COVID-19 because they are more abundant and stable than the RNA molecules on which common RT-PCR tests rely.
Sheetal Tushir, doctoral student and first author of the article, says: “The best thing we can [hope to] see in this century is the use of mass spectrometry as a basic technique for diagnosis.