Severe acute respiratory syndrome coronavirus 2

Its infectious particles enclose an RNA genome in a lipid membrane, with protein spikes projecting from the surface.

The four main structural proteins are spike (S), membrane (M), envelope (E) and nucleocapsid (N).

N associates with the viral RNA inside the particle, while the membrane carries the proteins involved in the particle’s outer organization.

A spike is a complex of three protein subunits, not simply a rigid point on a cartoon sphere.

The spike binds the host-cell receptor ACE2, and changes in its shape help bring viral and cellular membranes together for fusion.

Ke and colleagues examined spikes on intact virus particles, making the surface of the particle itself part of the structural investigation.

The genome is positive-sense RNA: after entry, it can act as a message that the host cell translates to produce viral replication proteins.

The replication system makes complementary negative-sense RNA intermediates, which provide templates for new positive-sense genomes and viral messages.

Thus, making a new particle involves producing its RNA and proteins and assembling them, rather than a virus cell growing and splitting in two.

In a 2020 study of infected cultured cells, Klein and colleagues found RNA filaments within double-membrane compartments and examined particles forming at intracellular membranes.

These observations connect genome replication with the membrane remodeling that accompanies infection.

During assembly, viral components become enclosed by membrane as particles bud into an intracellular compartment.

The finished particle therefore combines virus-encoded components with a membrane acquired from the infected cell.

SARS-CoV-2 spreads through virus-containing droplets and small particles released by infected people, including people who do not have symptoms.

Other people may inhale these particles, or particles may reach the eyes, nose or mouth.

Although COVID-19 most often involves respiratory symptoms, it can also affect other organs.

Some people develop Long COVID, including after an initial illness that was mild or had no recognized symptoms.

A picture of the viral surface explains organization, but it is not a clinical test or a prediction of what will happen to a particular person.

The Ensembl COVID-19 reference portal identifies its assembly as Wuhan-Hu-1, with nucleotide accession MN908947.3 and assembly accession GCA_009858895.3.

That reference contains 29,903 nucleotides; the number describes this sequence, not a guarantee that every SARS-CoV-2 genome has exactly the same length.

A versioned reference gives researchers a specified sequence against which to describe differences.

Viruses change over time, so observations about one sequence or historical sample should not be treated as a complete description of every later variant.

NCBI Taxonomy record 2697049 is named Severe acute respiratory syndrome coronavirus 2, but its Browser displayed the rank “no rank” when checked on 6 September 2026.

Its displayed lineage leads through Sarbecovirus to Betacoronavirus pandemicum.

The virus name, this NCBI record and the species name are therefore distinct labels, not interchangeable identifiers for an individual collected sample.

Are SARS-CoV-2 and COVID-19 the same thing?

No: SARS-CoV-2 names the virus, whereas COVID-19 names the disease it causes.

Does a spike structure identify the danger of a new variant?

A structural study shows molecular organization under its study conditions; on its own it does not measure the clinical effects of a later variant.

Is a reference genome the same as the virus in every infected person?

No: Wuhan-Hu-1 is the named reference used by this portal, while variant diversity and an individual infection are different questions.

The supplied normalized document binds ncbi_taxonomy:2697049 to rank isolate and is_higher_taxon=true in a local snapshot whose content_updated_at is 30 August 2026, 22:27:33 UTC.

The independent Browser observation on 6 September 2026 instead displays no rank, with Betacoronavirus pandemicum in the lineage.

The available prior audit does not establish the exact original upstream response, its hash or a dated NCBI rank-change event.

Preserve the historical local assertion and the current endpoint observation separately; neither the historical template flag nor the word isolate establishes a physical specimen identity.

The inspected reference page identifies ASM985889v3, GCA_009858895.3 and MN908947.3, an assembly dated January 2020, a database version of 104.1 and an Ensembl COVID-19 site version of 3, dated January 2022.

An access date in 2026 does not turn this versioned portal into a 2026 assembly release.

The 29,903-nucleotide length belongs to that RNA reference; the portal’s generic “Base Pairs” field label does not make the genome double-stranded DNA.

Klein et al. observed replication compartments and particle assembly in cultured cell models, so the article does not recast their images as a direct chronology inside a patient.

The Ke et al. contribution was checked through its author-hosted abstract, not as a fully read paper.

Its associated EMDB entry EMD-11497 specifically describes a spike reconstruction with three closed receptor-binding domains and lists fitted model 6zwv.

That entry is an identifiable structural state, not evidence that all spikes always adopt it.

The inspected MSL landing record was published on 20 March 2026, is labeled repository version v3, and lists ICTV_Master_Species_List_2025_MSL41.v1.xlsx.

The corrected VMR landing record was published on 29 July 2026, is labeled repository version v5, and lists VMR_MSL41.v1.20260729.xlsx.

Repository versions and workbook versions are different labels, and these metadata observations do not certify a workbook row or an exact NCBI-to-ICTV identifier mapping.