Molecular Mechanisms of SARS-CoV-2 and COVID-19

The emergence of SARS-CoV-2 has spurred extensive investigation into the molecular underpinnings of viral entry, replication and pathogenesis. Central to host invasion is the spike glycoprotein, whose receptor-binding domain (RBD) engages angiotensin-converting enzyme 2 (ACE2) on target cells, initiating large-scale conformational changes that drive membrane fusion. Following entry, the viral RNA genome is translated into polyproteins that are processed by viral proteases into functional units, including the RNA-dependent RNA polymerase responsible for genome replication and transcription. The subgenomic RNAs thus generated encode structural and accessory proteins that assemble into progeny virions. Host factors, such as endosomal proteases and cellular chaperones, modulate these processes, while innate immune sensing of viral RNA triggers interferon responses. In severe cases, dysregulated cytokine production and lymphopenia contribute to tissue damage and acute respiratory distress. Structural mapping of viral components has informed the design of antiviral inhibitors targeting the polymerase active site and protease cleavage pockets. Concurrently, neutralising antibodies directed at the RBD and fusion machinery underpin vaccine efficacy and therapeutic antibody development. Together, these findings offer a coherent picture of how SARS-CoV-2 co-opts host pathways and how molecular targets may be exploited to curb infection.

Research from Nature Portfolio

Recent studies have revealed the complete genome sequence of the novel coronavirus, clarifying its close relationship to bat-derived Sarbecoviruses and delineating key mutations in spike and accessory proteins that may influence host adaptation and transmissibility. Phylogenetic analysis of early isolates defined distinct genetic lineages and highlighted hotspots of variation within the spike RBD and ORF8, setting the stage for downstream functional studies. More recently, a programmable DNA nanobait system has been developed to detect multiple respiratory viruses, including SARS-CoV-2 variants, in a single assay. This approach employs toehold-mediated strand displacement to confer single-nucleotide specificity and uses nanopore sensing for rapid, amplification-free readout. By discriminating native viral RNA sequences from clinical swabs, this platform demonstrates a scalable route to variant surveillance and point-of-care diagnostics.

Molecular Mechanisms of SARS-CoV-2 and COVID-19 publication trend

The graph below shows the total number of articles in molecular mechanisms of sars-cov-2 and covid-19 across all publications each year (not limited to Nature Index journals).

Technical terms

Spike glycoprotein: A trimeric viral surface protein that mediates attachment to host cells and membrane fusion.

Receptor-binding domain (RBD): A subregion of the spike that directly engages ACE2 to initiate cell entry.

Angiotensin-converting enzyme 2 (ACE2): A cellular membrane enzyme that serves as the primary entry receptor for SARS-CoV-2.

Toehold-mediated strand displacement: A nucleic acid reaction in which an unpaired ‘toehold’ region initiates the exchange of complementary strands.

Nanopore sensing: A single-molecule detection technique that measures ionic current changes as nucleic acids translocate through a nanoscale pore.

Cytokine storm: An excessive, uncontrolled release of proinflammatory cytokines leading to host tissue damage.

References

1. Simultaneous identification of viruses and viral variants with programmable DNA nanobait. Nature Nanotechnology (2023).
2. A new coronavirus associated with human respiratory disease in China. Nature (2020).
3. COVID-19 pandemic: Insights into structure, function, and hACE2 receptor recognition by SARS-CoV-2. PLOS Pathogens (2020).
4. The Immune Response and Immunopathology of COVID-19. Frontiers in Immunology (2020).
5. Neutralizing Antibodies against SARS-CoV-2 and Other Human Coronaviruses. Trends in Immunology (2020).