Crystal structure of COVID-19
The COVID-19 replicase gene encoded two polyproteins, pp1a and pp1ab with molecular weigh t450 and 750 KD respectively, these polyproteins are required for viral replication and transcription. In the proteolytic process, the functional polypeptides of spike, membrane, envelope, nucleoprotein, replicase and polymerase are released from polyproteins. This process was carried out by a chymotrypsin-fold proteinase namely main protease. The main protease is a vital role in polyprotein processing and virus maturation, hence, it is considered to be an attractive target for antiviral drug design as an approach toward COVID-19 treatment.