Structure and Genome of SARS-CoV-2 (COVID-19) with diagram


Coronaviruses are a group of related RNA viruses that cause diseases in mammals and birds. In humans, they can cause respiratory tract infections that can range from mild to lethal, such as the common cold, severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and coronavirus disease 2019 (COVID-19) .

Coronaviruses are named for the spikes that protrude from their surfaces, resembling a crown or the sun`s corona. They belong to the subfamily Orthocoronavirinae, which is divided into four genera: Alphacoronavirus, Betacoronavirus, Gammacoronavirus, and Deltacoronavirus. Each genus includes different species of coronaviruses that infect different hosts.

Coronaviruses are enveloped, positive-sense, single-stranded RNA viruses with a genome size of about 30 kilobases . They have four structural proteins: spike (S), envelope (E), membrane (M), and nucleocapsid (N) . The S protein is responsible for binding to the host cell receptor and mediating viral entry. The E and M proteins form the viral envelope and are involved in virus assembly and release. The N protein binds to the viral RNA and forms the nucleocapsid inside the envelope .

Coronaviruses can infect both animals and humans, and can cause zoonotic diseases that jump from one species to another . Some of the known animal reservoirs of coronaviruses include bats, camels, civets, pangolins, and minks . The transmission of coronaviruses between animals and humans can occur through direct contact, aerosols, or contaminated surfaces .

The most recent coronavirus outbreak is caused by a novel coronavirus called SARS-CoV-2, which was first detected in Wuhan, China in December 2019 . This virus causes COVID-19, a disease that can range from mild to severe respiratory illness with symptoms such as fever, cough, shortness of breath, loss of taste or smell, and sometimes pneumonia or organ failure . As of June 2023, COVID-19 has infected more than 200 million people and caused more than 4 million deaths worldwide.

The best way to prevent and control the spread of coronaviruses is to be well informed about the disease and how the virus spreads. Some of the preventive measures include staying at least 1 metre apart from others, wearing a properly fitted mask, washing hands or using an alcohol-based rub frequently, getting vaccinated when it`s available and following local guidance. It is also important to practice respiratory etiquette, such as coughing into a flexed elbow, and to stay home and self-isolate if feeling unwell.

In this article, we will focus on the detailed structure and genomic organization of SARS-CoV-2, the causative agent of COVID-19. We will also discuss the role of the spike glycoprotein in viral infection and its implications for vaccine development and treatment. Finally, we will conclude with some future research directions on coronaviruses.