S4T3K4 · S4T3K4_9INFA

Function

function

Catalyzes the removal of terminal sialic acid residues from viral and cellular glycoconjugates. Cleaves off the terminal sialic acids on the glycosylated HA during virus budding to facilitate virus release. Additionally helps virus spread through the circulation by further removing sialic acids from the cell surface. These cleavages prevent self-aggregation and ensure the efficient spread of the progeny virus from cell to cell. Otherwise, infection would be limited to one round of replication. Described as a receptor-destroying enzyme because it cleaves a terminal sialic acid from the cellular receptors. May facilitate viral invasion of the upper airways by cleaving the sialic acid moities on the mucin of the airway epithelial cells. Likely to plays a role in the budding process through its association with lipid rafts during intracellular transport. May additionally display a raft-association independent effect on budding. Plays a role in the determination of host range restriction on replication and virulence. Sialidase activity in late endosome/lysosome traffic seems to enhance virus replication.

Caution

Lacks conserved residue(s) required for the propagation of feature annotation.

Catalytic activity

  • Hydrolysis of alpha-(2->3)-, alpha-(2->6)-, alpha-(2->8)- glycosidic linkages of terminal sialic acid residues in oligosaccharides, glycoproteins, glycolipids, colominic acid and synthetic substrates.
    EC:3.2.1.18 (UniProtKB | ENZYME | Rhea)

Cofactor

Ca2+ (UniProtKB | Rhea| CHEBI:29108 )

Activity regulation

Inhibited by the neuraminidase inhibitors zanamivir (Relenza) and oseltamivir (Tamiflu). These drugs interfere with the release of progeny virus from infected cells and are effective against all influenza strains. Resistance to neuraminidase inhibitors is quite rare.

Features

Showing features for binding site, active site.

Type
IDPosition(s)Description
Binding site118substrate
Active site151Proton donor/acceptor
Binding site152substrate
Binding site276-277substrate
Binding site292substrate
Binding site293Ca2+ (UniProtKB | ChEBI)
Binding site297Ca2+ (UniProtKB | ChEBI)
Binding site324Ca2+ (UniProtKB | ChEBI)
Binding site371substrate
Active site406Nucleophile

GO annotations

AspectTerm
Cellular Componenthost cell plasma membrane
Cellular Componentmembrane
Cellular Componentvirion membrane
Molecular Functionexo-alpha-(2->3)-sialidase activity
Molecular Functionexo-alpha-(2->6)-sialidase activity
Molecular Functionexo-alpha-(2->8)-sialidase activity
Molecular Functionmetal ion binding
Biological Processcarbohydrate metabolic process
Biological Processviral budding from plasma membrane

Keywords

Enzyme and pathway databases

Names & Taxonomy

Protein names

  • Recommended name
    Neuraminidase
  • EC number

Gene names

    • Name
      NA

Organism names

  • Taxonomic identifier
  • Strain
    • A/mallard/Sweden/99851/2009
  • Taxonomic lineage
    Viruses > Riboviria > Orthornavirae > Negarnaviricota > Polyploviricotina > Insthoviricetes > Articulavirales > Orthomyxoviridae > Alphainfluenzavirus > Alphainfluenzavirus influenzae > Influenza A virus

Accessions

  • Primary accession
    S4T3K4

Subcellular Location

Host membrane
; Single-pass type II membrane protein
Virion membrane
Host apical cell membrane
; Single-pass type II membrane protein
Note: Preferentially accumulates at the apical plasma membrane in infected polarized epithelial cells, which is the virus assembly site. Uses lipid rafts for cell surface transport and apical sorting. In the virion, forms a mushroom-shaped spike on the surface of the membrane.

Features

Showing features for transmembrane.

TypeIDPosition(s)Description
Transmembrane12-37Helical

Keywords

PTM/Processing

Features

Showing features for disulfide bond.

TypeIDPosition(s)Description
Disulfide bond92↔417
Disulfide bond124↔129
Disulfide bond183↔230
Disulfide bond232↔237
Disulfide bond278↔291
Disulfide bond280↔289

Post-translational modification

N-glycosylated.

Keywords

Interaction

Subunit

Homotetramer.

Family & Domains

Features

Showing features for region, compositional bias.

Type
IDPosition(s)Description
Region11-33Involved in apical transport and lipid raft association
Region91-469Head of neuraminidase
Compositional bias325-342Polar residues
Region325-349Disordered

Domain

Intact N-terminus is essential for virion morphogenesis. Possess two apical sorting signals, one in the ectodomain, which is likely to be a glycan, and the other in the transmembrane domain. The transmembrane domain also plays a role in lipid raft association.

Sequence similarities

Belongs to the glycosyl hydrolase 34 family.

Keywords

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    469
  • Mass (Da)
    52,007
  • Last updated
    2013-10-16 v1
  • Checksum
    3BD01B34A14B3C73
MNPNQKIITIGSVSLTIATVCFLMQIAILATTITLHFKQNECSIPSNNQVMPCEPIIVERNITEIVYLNNTTIEKELCPKLTEYRNWSKPQCQITGFAPFSKDNSIRLSAGGDIWVTREPYVSCSPNKCYQFALGQGTTLDNKHSNGTIHDRIPHRTLLMNELGVPFHLGTKQVCIAWSSSSCHDGRAWLHVCVTGDDRNATASFIYDGMLVDSIGSWSQNILRTQESECVCINGTCTVVMTDGSASGRADTRILFIKEGKIVHISPLSGSAQHIEECSCYPRYPDVRCVCRDNWKGSNRPIIDINMADYSIDSSYVCSGLVGDTPRNDDSSSNSNCKDPNNERGNPGVKGWAFDYGSDVWMGRTISKDSRSGYETFRVIGGWTTANSKSQVNRQVIVDNNNWSGYSGIFSVEGKSCINRCFYVELIRGRPQETRVWWTSNSIVVFCGTSGTYGTGSWPDGANINFMPI

Features

Showing features for compositional bias.

TypeIDPosition(s)Description
Compositional bias325-342Polar residues

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
JX566191
EMBL· GenBank· DDBJ
AFT64679.1
EMBL· GenBank· DDBJ
Viral cRNA

Similar Proteins

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