Understanding the Molecular Biology of SARS-CoV-2 and the COVID-19 Pandemic: A Review

Abstract

Coronaviruses are named after the crown-like spike proteins on their surface. In the 21st century, three coronaviruses, namely severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), SARS-CoV, and Middle East respiratory syndrome related coronavirus (MERS-CoV), have emerged in the human population, presumably evolving from pathogens infecting other animals. Coronaviruses are enveloped viruses responsible for 15–30% of the atypical pneumonia cases in humans worldwide. The current coronavirus disease 2019 (COVID-19) pandemic is caused by the newest SARS virus, SARS-CoV-2, an enveloped, positive-sense, single-stranded RNA betacoronavirus of the family Coronaviridae. As of April 2021, the World Health Organization has reported more than 3 million deaths from COVID-19 and more than 140 million people have been infected with the virus, thereby making it the worst SARS pandemic of all time. Here, I review the current understanding of the molecular biology of coronaviruses and their host interactions, bringing together knowledge of the infection process to aid in the development of therapeutic drugs and/or vaccines against SARS-CoV-2. I also briefly overview the current situation of available treatments, vaccinations, and emerging strains.

Recapping the Features of SARS-CoV-2 and Its Main Variants: Status and Future Paths

“…SARS-CoV-2, the etiological agent of COVID-19, belongs to the Betacoronavirus genus, the same as MERS-CoV and SARS-CoV according to clustering based on genetic similarities [ 8 ]. These three viruses emerged in the present century, switching from animal hosts to the human species, with the last of them, SARS-CoV-2, spreading at pandemic level [ 9 ]. The term “ Coronavirus ” was coined due to the crown shape that their proteins imitate when observed by electron microscopy.…”

Inhibitory effect of honokiol on furin-like activity and SARS-CoV-2 infection

“… 1 The entry of SARS-CoV-2 into host cells is mediated by the transmembrane spike glycoprotein (S protein), which forms homotrimers extending from the virus envelope. 2 , 3 , 4 The S protein is processed and activated by cellular proteases, including a transmembrane protease serine 2 (TMPRSS2), cathepsin, and furin 5 , 6 , 7 ; it comprises two functional subunits, S1 and S2. The S1 subunit is involved in binding to the host cell receptor, and the S2 subunit participates in the fusion of the virus envelope and host cell membrane.…”

Potential of Natural Alkaloids From Jadwar (Delphinium denudatum) as Inhibitors Against Main Protease of COVID-19: A Molecular Modeling Approach

“…The genome sequence for the Wuhan-Hu-1 strain of SARS-CoV-2 is available from the GenBank with the accession number MN908947 (∼29,903 nucleotides) ( Wu et al, 2020 ). The SARS-CoV-2 genome contains 14 open reading frames (ORFs) encoding 27 proteins ( Alsobaie 2021 ). The 5′ untranslated region (UTR) end harbors ORF1a/b that produces a polyprotein which is posttranslationally cleaved into 16 different nonstructural proteins (nsp1–nsp16).…”

“…They include a papain-like protease (nsp3), main protease (M pro , 3CL pro , nsp5), nsp7–nsp8 primase complex, primary RNA-dependent RNA polymerase (RdRp; nsp12), helicase/triphosphatase (nsp13), exoribonuclease (nsp14), endonuclease (nsp15), and N7- and 2′-O-methyltransferases (nsp10/nsp16). The 3′-end of the SARS-CoV-2 contains ORFs which encode the four structural proteins, namely, E (envelope protein), M (membrane protein), N (nucleocapsid protein), and S (spike protein), as well as nine putative accessory factors ( Rastogi et al, 2020 ; Alsobaie 2021 ; Shamsi et al, 2021 ). The SARS-CoV-2 M pro (nsp5) is encoded by the major ORF1ab following posttranslational cleavage in the cytosol ( Ullrich and Nitsche 2020 ; Mengist et al, 2021 ).…”