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Protein

Neuraminidase

Gene

NA

Organism
Influenza B virus (strain B/Leningrad/179/1986)
Status
Reviewed-Annotation score: Annotation score: 4 out of 5-Protein inferred from homologyi

Functioni

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.UniRule annotation

Miscellaneous

The influenza B genome consist of 8 RNA segments. Genetic variation of hemagglutinin and/or neuraminidase genes results in the emergence of new influenza strains. The mechanism of variation can be the result of point mutations or the result of genetic reassortment between segments of two different strains.

Catalytic activityi

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.UniRule annotation

Cofactori

Ca2+UniRule annotation

Enzyme regulationi

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.UniRule annotation

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Binding sitei115SubstrateUniRule annotation1
Active sitei148Proton donor/acceptorUniRule annotation1
Binding sitei149SubstrateUniRule annotation1
Binding sitei291SubstrateUniRule annotation1
Metal bindingi292Calcium; via carbonyl oxygenUniRule annotation1
Metal bindingi323CalciumUniRule annotation1
Binding sitei373SubstrateUniRule annotation1
Active sitei408NucleophileUniRule annotation1

GO - Molecular functioni

GO - Biological processi

Keywordsi

Molecular functionGlycosidase, Hydrolase
LigandCalcium, Metal-binding

Names & Taxonomyi

Protein namesi
Recommended name:
NeuraminidaseUniRule annotation (EC:3.2.1.18UniRule annotation)
Gene namesi
Name:NAUniRule annotation
OrganismiInfluenza B virus (strain B/Leningrad/179/1986)
Taxonomic identifieri11536 [NCBI]
Taxonomic lineageiVirusesssRNA virusesssRNA negative-strand virusesOrthomyxoviridaeInfluenzavirus B
Virus hostiHomo sapiens (Human) [TaxID: 9606]

Subcellular locationi

  • Virion membrane UniRule annotation
  • Host apical cell membrane UniRule annotation; Single-pass type II membrane protein UniRule annotation

  • 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.UniRule annotation

Topology

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Topological domaini1 – 11IntravirionUniRule annotationAdd BLAST11
Transmembranei12 – 34HelicalUniRule annotationAdd BLAST23
Topological domaini35 – 465Virion surfaceUniRule annotationAdd BLAST431

GO - Cellular componenti

Keywords - Cellular componenti

Host cell membrane, Host membrane, Membrane, Virion

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
ChainiPRO_00000787331 – 465NeuraminidaseAdd BLAST465

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Glycosylationi55N-linked (GlcNAc...) asparagine; by hostUniRule annotation1
Glycosylationi63N-linked (GlcNAc...) asparagine; by hostUniRule annotation1
Disulfide bondi86 ↔ 419UniRule annotation
Disulfide bondi121 ↔ 126UniRule annotation
Glycosylationi143N-linked (GlcNAc...) asparagine; by hostUniRule annotation1
Disulfide bondi181 ↔ 228UniRule annotation
Disulfide bondi230 ↔ 235UniRule annotation
Disulfide bondi276 ↔ 290UniRule annotation
Disulfide bondi278 ↔ 288UniRule annotation
Glycosylationi283N-linked (GlcNAc...) asparagine; by hostUniRule annotation1
Glycosylationi294N-linked (GlcNAc...) asparagine; by hostUniRule annotation1
Disulfide bondi317 ↔ 336UniRule annotation
Disulfide bondi423 ↔ 446UniRule annotation

Post-translational modificationi

N-glycosylated.UniRule annotation

Keywords - PTMi

Disulfide bond, Glycoprotein

Interactioni

Subunit structurei

Homotetramer.UniRule annotation

Structurei

3D structure databases

ProteinModelPortaliP67923.
SMRiP67923.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Region

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Regioni13 – 35Involved in apical transport and lipid raft associationUniRule annotationAdd BLAST23
Regioni38 – 85Hypervariable stalk regionUniRule annotationAdd BLAST48
Regioni88 – 465Head of neuraminidaseUniRule annotationAdd BLAST378
Regioni274 – 275Substrate bindingUniRule annotation2

Domaini

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.UniRule annotation

Sequence similaritiesi

Belongs to the glycosyl hydrolase 34 family.UniRule annotation

Keywords - Domaini

Signal-anchor, Transmembrane, Transmembrane helix

Family and domain databases

CDDicd15483. Influenza_NA. 1 hit.
HAMAPiMF_04071. INFV_NRAM. 1 hit.
InterProiView protein in InterPro
IPR001860. Glyco_hydro_34.
IPR033654. Sialidase_Influenza_A/B.
IPR011040. Sialidases.
PfamiView protein in Pfam
PF00064. Neur. 1 hit.
SUPFAMiSSF50939. SSF50939. 1 hit.

Sequencei

Sequence statusi: Complete.

P67923-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MLPSTIQTLT LFLTSGGVLL SLYVSASLSY LLYSDILLKF SPKITAPTMT
60 70 80 90 100
LDCANASNVQ AVNRSATKEM TFLLPEPEWT YPRLSCQGST FQKALLISPH
110 120 130 140 150
RFGEARGNSA PLIIREPFIA CGPKECKHFA LTHYAAQPGG YYNGTREDRN
160 170 180 190 200
KLRHLISVKL GKIPTVENSI FHMAAWSGSA CHDGREWTYI GVDGPDSNAL
210 220 230 240 250
IKIKYGEAYT DTYHSYANNI LRTQESACNC IGGDCYLMIT DGSASGISEC
260 270 280 290 300
RFLKIREGRI IKEIFPTGRV EHTEECTCGF ASNKTIECAC RDNNYTAKRP
310 320 330 340 350
FVKLNVETDT AEIRLMCTET YLDTPRPDDG SITGPCESNG DKGRGGIKGG
360 370 380 390 400
FVHQRMASKI GRWYSRTMSK TERMGMELYV KYDGDPWTDS DALAPSGVMV
410 420 430 440 450
SIKEPGWYSF GFEIKDKKCD VPCIGIEMVH DGGKKTWHSA ATAIYCLMGS
460
GQLLWDTVTG VDMAL
Length:465
Mass (Da):51,382
Last modified:October 11, 2004 - v1
Checksum:iFD402484907888CA
GO

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
M30632 Genomic RNA. Translation: AAA43731.1.
PIRiC46347.

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into one UniRef entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.

Entry informationi

Entry nameiNRAM_INBLN
AccessioniPrimary (citable) accession number: P67923
Secondary accession number(s): P16193, P16197
Entry historyiIntegrated into UniProtKB/Swiss-Prot: October 11, 2004
Last sequence update: October 11, 2004
Last modified: June 7, 2017
This is version 68 of the entry and version 1 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programViral Protein Annotation Program

Miscellaneousi

Documents

  1. Glycosyl hydrolases
    Classification of glycosyl hydrolase families and list of entries
  2. SIMILARITY comments
    Index of protein domains and families