History Of Severe acute respitory syndrome (SARS) Coronavirus

Sars Coronavirus is the virus that causes SARS.

The morphology of the SARS coronavirus is characteristic of the coronavirus family as a whole. These viruses have large pleomorphic( is the occurrence of two or more structural forms during a life cycle, especially of certain plants, including many marine plants such as Mastocarpus stellatus.)spherical particles with bulbous surface projections that form a corona( A corona is a type of plasma )around particles. The envelop of the virus contains lipid(Fats) and appears to consist of a distinct pair of electron dense shells. The internal component of the shell is a single-stranded helical ribonucleoprotein. There are also long surface projections that protrude from the lipid envelop.

The biology of SARS coronavirus is a positive and single stranded RNA(Ribonucleic acid ) virus belonging to a family of enveloped coronaviruses. It  is one of the largest among RNA viruses. SARS is similar to other coronaviruses. The SARS coronavirus has 13 known genes and 14 known proteins.  The polyproteins are then processed by enzymes. Product proteins from the processing includes various replicative enzymes such as RNA dependent polymerase, RNA helicase, and proteinase. SARS-Coronavirus follows the replication strategy typical of the Coronavirus genus.

The evoultion of SARS is most closely related to group 2 coronaviruses.The closest outgroup to the coronaviruses are the toroviruses.SARS was determined to be an early split off from the group 2 coronaviruses based on a set of conserved domains that it shares with group 2. A main difference between group 2 coronovirus and SARS is the nsp3.