Thursday, February 27, 2020

Coronavirus (WARS) Uses HIV Packing Mechanism


SCMP |  The new coronavirus has an HIV-like mutation that means its ability to bind with human cells could be up to 1,000 times as strong as the Sars virus, according to new research by scientists in China and Europe.

The discovery could help to explain not only how the infection has spread but also where it came from and how best to fight it.

Scientists showed that Sars (severe acute respiratory syndrome) entered the human body by binding with a receptor protein called ACE2 on a cell membrane. And some early studies suggested that the new coronavirus, which shares about 80 per cent of the genetic structure of Sars, might follow a similar path.

But the ACE2 protein does not exist in large quantities in healthy people, and this partly helped to limit the scale of the Sars outbreak of 2002-03, in which infected about 8,000 people around the world.

Other highly contagious viruses, including HIV and Ebola, target an enzyme called furin, which works as a protein activator in the human body. Many proteins are inactive or dormant when they are produced and have to be “cut” at specific points to activate their various functions.

When looking at the genome sequence of the new coronavirus, Professor Ruan Jishou and his team at Nankai University in Tianjin found a section of mutated genes that did not exist in Sars, but were similar to those found in HIV and Ebola.

“This finding suggests that 2019-nCoV [the new coronavirus] may be significantly different from the Sars coronavirus in the infection pathway,” the scientists said in a paper published this month on Chinaxiv.org, a platform used by the Chinese Academy of Sciences to release scientific research papers before they have been peer-reviewed.

“This virus may use the packing mechanisms of other viruses such as HIV.”

According to the study, the mutation can generate a structure known as a cleavage site in the new coronavirus’ spike protein.

The virus uses the outreaching spike protein to hook on to the host cell, but normally this protein is inactive. The cleavage site structure’s job is to trick the human furin protein, so it will cut and activate the spike protein and cause a “direct fusion” of the viral and cellular membranes.

Compared to the Sars’ way of entry, this binding method is “100 to 1,000 times” as efficient, according to the study.

Just two weeks after its release, the paper is already the most viewed ever on Chinarxiv.