Abstract

 The coronavirus family is named for the large spike protein molecules found on the pathogen exterior, which give the virus a crown-like appearance, the coronavirus genome is the biggest among RNA viruses. There are about seven viruses capable of infecting humans: in the alpha genus, there are 229E and NL63, and in the beta genus, there are OC-43, HKU1, MERS-CoV, SARS-CoV, and SARS-CoV-2. The severe acute respiratory syndrome coronavirus (SARS-CoV) is a positive-stranded RNA virus. In humans, the virus is transmitted through respiratory tract droplets or discharges from diseased persons. The reservoir hosts for MERS-CoV are camels, while those for SARS-CoV are most likely bats. SARS-CoV-2 infecting a snake may have been transmitted by zoonotic transmission in a palm civet. The Chinese viruses SARS-Co- -2 and SARS-CoV have many things in common, including contact with wild animals.However, both SARS-CoV-2 and MERS-CoV have the ability to persist and spread the illness even when the infected individuals are untreated. SARS-S1 CoV-2's components of the spike proteins have 75% structural commonality with SARS-like CoVs in bats and SARS-CoV. According to genetic comparisons, the latest investigations have proven that SARS-CoV-2 targets angiotensin-converting enzyme type-2 (ACE-2) in humans. However, SARS-CoV-2 possesses an identical receptorbinding domain (RBD) pattern to SARS-CoV, with differences in amino acid sequences at certain vital positions. The RBD is also found in the C-domain S1 component of MERS-CoV's S protein (Spike). Conversely, in contrast to SARS-CoV, MERS-CoV uses a dipeptidyl-peptidase-4 (DPP-4) helix as its binding site. Similarly, MERS-RBD coronaviruses (CoVs) have an extra subdomain that functions as the receptor-binding motif (RBM).