An international team of scientists, led by University of Bristol Professors Christiane Schaffitzel and Imre Berger, have unearthed a druggable pocket in the SARS-CoV-2 Spike protein that could be used to stop the virus in its tracks. ‘Spike protein’ refers to the multiple copies of glycoprotein that surround SARS-CoV-2. These ‘spikes’ bind to human cells, allowing the virus to penetrate the cells and replicate, damaging as they go. The collaborative study of SARS-CoV-2 is comprised of experts from Bristol UNCOVER Group, Bristol biotech Imophoron Ltd, the Max Planck Institute in Heidelberg and Geneva Biotech Sàrl.
The team analysed the SARS-CoV-2 Spike protein at near atomic resolution by applying electron cryo-microscopy (Cryo-EM) and Oracle’s high-performance cloud computing to produce a 3D image of the virus’s molecular composition. After getting a look at the virus up-close, the scientists spotted a potential ‘game changer’ in defeating the current pandemic.
The researchers spotted the presence of a free fatty acid; linoleic acid (LA), hidden away in a pocket within the Spike protein. LA is vital to most cellular functions in humans. It is not naturally produced by the body, so humans must intake LA through diet. The acid helps to maintain cell membranes in the lungs, and regulates inflammation and immune modulation, which are all the functions that are implicated in Covid-infected patients. Professor Berger, Director of the Max Planck Bristol Centre for Minimal Biology, confirms that “the virus that is causing all this chaos, according to our data, grabs and holds on to exactly this molecule – basically disarming much of the body’s defences.”
Professor Schaffitzel, from the University of Bristol’s School of Biochemistry, explained: “From other diseases we know that tinkering with LA metabolic pathways can trigger systemic inflammation, acute respiratory distress syndrome and pneumonia. These pathologies are all observed in patients suffering from severe COVID-19. A recent study of COVID-19 patients showed markedly reduced LA levels in their sera.”
The exploitation of the druggable pocket containing LA in SARS-CoV-2 could be the key to manipulating the virus. The discovery of a druggable pocket has previously been successfully exploited in rhinovirus, which causes the common cold. In rhinovirus, small molecules were tightly bound to the pocket to distort its molecular structure, and prevent its infectivity in human cells. The team are optimistic that their discovery of a similar pocket in SARS-CoV-2 can be used to develop small molecule anti-viral drugs against it.
Professor Berger adds: “Our discovery provides the first direct link between LA, COVID-19 pathological manifestations and the virus itself. The question now is how to turn this new knowledge against the virus itself and defeat the pandemic.”