ABSTRACT
An ongoing pandemic Coronavirus disease (COVID-19), caused by a newly emerged Coronavirus, SARS-CoV-2 has affected millions of people globally. One of the most crucial structural proteins of SARS-CoV-2 is the Spike glycoprotein (S-glycoprotein), for which the first de novo modelling was envisaged by our group in early 2020, and was superimposed to its predecessor SARS-CoV S-glycoprotein, to determine structural divergence, glycosylation and antigenic variation between SARS-CoV-2 and SARS-CoV. S-glycoprotein is involved in binding with the cellular receptor, membrane fusion, internalization via angiotensin-converting enzyme 2 (ACE2) receptor, and tissue tropism. Upon internalization into the target host cells, the viral genome encodes two precursor polypeptides which get processed into 16 mature nonstructural proteins that play a crucial role in replication and transcription of SARS-CoV-2. Currently S-glycoprotein is one of the most vital targets for vaccine and therapeutics development for COVID-19.
ABSTRACT
In December 2019, suddenly 54 cases of viral pneumonia emerged in Wuhan, China, caused by some unknown microorganism. The virus responsible for these pneumonia infections was identified as novel coronavirus of the family Coronaviridae. The novel coronavirus was renamed as COVID-19 by WHO. Infection from the virus has since increased exponentially and has spread all over the world in more than 196 countries. The WHO has declared a Public Health Emergency of International Concern due to the outbreak of COVID-19. The virus is highly infectious and can cause human-to-human transmission. Every 24 h, cases of COVID-19 increase severalfolds. The WHO is monitoring the SARS-CoV-2 spread very closely via a global surveillance system. The current situation demands the enforcement of strict laws which would help in inhibiting the further spread of COVID-19. Social distancing, international travel restrictions to affected countries, and hygiene are three important ways to nullify SARS-CoV-2.Government and private organizations need to come forward and work together during this pandemic. Public awareness, social distancing, and sterilization must be maintained to neutralize the viral infection, especially in major hot spots.
ABSTRACT
The positive-strand RNA viruses, severe acute respiratory syndrome coronavirus (SARS-CoV) and recently emerged COVID-19 epidemics, demonstrated the transmission capability of the coronaviruses by crossing the species barrier and emergence in humans. The source of coronavirus disease 2019 (COVID-19) is severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), firstly reported in December 2019 at Wuhan, China. COVID-19 is a kind of viral pneumonia. The outbreak of SARS-CoV-2 (COVID-19) has been reported as the introduction of the third highly pathogenic coronavirus which crossed the species barrier and spread into the human population. Severe acute respiratory syndrome coronavirus (SARS-CoV) and the Middle East respiratory syndrome coronavirus (MERS-CoV) were the first two epidemic viruses, respectively, in the twenty-first century. Introduction of the 2019 novel coronaviruses (2019-nCoV) in human population is a worldwide concern, and this might have generated via RNA recombination among the previous reported coronaviruses. The COVID-19 is spreading in an alarming rate, and till date no vaccine or specific medicines are available in the market. The newly emerged coronavirus COVID-19 is strongly related to SARS-CoV except little dissimilarity. In this chapter, we will discuss about the alterations and variations in antigenicity, structural changes, and RNA recombination which might be responsible for the COVID-19 emergence.