At the beginning of its existence, Covid-19 gained an ability that would prove decisive in its relationship with human beings. The virus has seen a seemingly small change in its genetic code. It was probably an unfortunate accident – a piece of genetic information from another virus was confused with that of the coronavirus while they were both infecting a bat.
However, instructions that altered a key part of the virus – its peak protein – were included in this small piece of the genome. This important protein studies the outside of the coronavirus and is the part that attaches to the outside of the cells, helping the rest of the virus to sneak inside, where it can replicate.
This change in the Covid-19 peak protein meant that it could hijack an enzyme found in the human body called furin. This enzyme acts as a pair of molecular scissors, normally cutting open hormones and growth factors to activate them. But when the furin breaks off part of the Covid-19 peak protein, which is normally folded into a series of loops outside the virus, it opens like a hinge.
“This exposes a new sequence in the spike protein,” says Yohei Yamauchi, a reader in viral cell biology at the University of Bristol, UK, who studied how this change could have caused Covid-19 to become more infectious. to people. “It’s one of the changes that makes this virus really different from the previous coronaviruses that caused Sars and Mers.”
This new mutation meant that Covid-19 could suddenly cling to an important molecule found scattered outside the human respiratory cells called Neuropilin 1. This molecule helps transport material inside the cells even deeper into the tissues – the mutation was like how you would give the keys to Covid-19 to a new door in our cells and it meant that the virus could replicate in greater numbers through the human airways.
Although this mutation was only one of the short existence of Covid-19, it proved to be important. Some researchers believe it could be one of the key mutations that allowed the coronavirus to jump species and begin to cause a rapidly spreading disease in humans. But almost as soon as he did, he began to catch other mutations.