Unique nCoV-2019 (Covid-19) Spike Glycoprotein Processing by Host Protease: Analysis and Implication on Infection

The current global pandemic outbreak of a novel type of coronavirus termed by the World Health Organization as COVID-19 became a grave concern and worry to human health and the world economy. Intense research efforts are now underway worldwide to combat and prevent the spread of this deadly disease. This zoonotic virus, a native to bat population, is most likely transmitted to a human via a host reservoir. Due to its close similarity to previously known SARS CoV (Severe Acute Respiratory Syndrome Corona Virus) of 2002 and related MERS CoV (Middle East Respiratory Syndrome Corona Virus) of 2012, it is also known as SARS CoV2. But unlike them, it is far too infectious, virulent and lethal. Among its various proteins, the surface spike glycoprotein “S” has drawn significant attention because of its implication in viral recognition and host-virus fusion process. A detailed comparative analysis of “S” proteins of SARS CoV (now called SARS CoV1), SARS CoV2 (COVID-19) and MERS CoV based on structure, sequence alignment, host cleavage sites, receptor binding domains, potential glycosylation and Cys-disulphide bridge locations has been performed. It revealed some key features and variations that may elucidate the high infection and virulence character of COVID-19. Moreover, this crucial information may become useful in our quest for COVID-19 therapeutics and vaccines.