Covid-19 (SARS-CoV-2) VS Sars-CoV; Summary of all things that healthcare providers should know |Biomedgrid

The corona viruses are members of a family of enveloped viruses that replicate in the cytoplasm of animal host cells. They are distinguished by the presence of a single-stranded plus-sense RNA genome about 30 kb in length that has a 5′ cap structure and 3′ polyadenylation tract. Upon infection of an appropriate host cell, the 5′-most open reading frame (ORF) of the viral genome is translated into a large polyprotein that is cleaved by viralencoded proteases to release several nonstructural proteins, including an RNA-dependent RNA polymerase (Rep) and an adenosine triphosphatase (ATPase) helicase (Hel). These proteins, in turn, are responsible for replicating the viral genome as well as generating nested transcripts that are used in the synthesis of the viral proteins. The mechanism by which these subgenomic mRNAs are made is not fully understood. The SARS-CoV genomes are about 30 kb in length. Its large RNA genome encodes four structural proteins, sixteen non-structural proteins and eight accessory proteins. SARS-CoV is a plus-strand RNA virus featuring a large single-stranded RNA genome of approximately 29 700 nucleotides. The genome is predicted to consist of atleast fourteen functional ORFs that encode three classes of proteins: two large polyproteins, pp1a and pp1ab, which are cleaved into sixteen non-structural proteins (nsps) required for viral RNA synthesis (and probablyother functions); four structural proteins (the S, E, M and N proteins), essential for viral assembly; and eight accessory proteins, which are thought unimportant in tissue culture but may provide a selective advantage in the infected host.