Spike S1

HCoV-HKU1, formally known as Human Coronavirus Hong Kong University 1, is a member of the Betacoronavirus genus within the Coronaviridae family. It was first identified in Hong Kong in 2005 and has since been detected in various parts of the world, causing respiratory infections ranging from asymptomatic to severe cases.
HCoV-HKU1 is an enveloped virus, meaning its genetic material is contained within a lipid membrane surrounded by structural proteins. This envelope is studded with glycoproteins, including the Spike Protein (S Protein), which plays a critical role in virus attachment and entry into host cells. The S Protein is a type I transmembrane protein that protrudes from the virus surface, serving as a bridge between the virus and its host cell receptor. Once the S Protein binds to its cognate receptor on the host cell surface, it triggers a series of events leading to the fusion of the viral and cellular membranes, allowing the release of the virus's genetic material into the host cell cytoplasm.