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Q6DPI6 (NRAM_I02A7) Reviewed, UniProtKB/Swiss-Prot

Last modified February 19, 2014. Version 55. Feed History...

Clusters with 100%, 90%, 50% identity | Documents (2) | Third-party data text xml rdf/xml gff fasta
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Protein attributes

Sequence length454 AA.
Sequence statusFragment.
Protein existenceInferred from homology

General annotation (Comments)

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.

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.

Cofactor

Binds 1 calcium ion By similarity.

Enzyme 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.

Subunit structure

Homotetramer By similarity.

Subcellular location

Virion membrane By similarity. Host apical cell membrane; Single-pass type II membrane protein By similarity. 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 By similarity.

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 By similarity.

Post-translational modification

N-glycosylated By similarity.

Miscellaneous

The influenza A 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.

Sequence similarities

Belongs to the glycosyl hydrolase 34 family.

Sequence annotation (Features)

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifier

Molecule processing

Chain‹1 – 454›454Neuraminidase
PRO_0000310940

Regions

Transmembrane‹1 – 13›13Helical; Potential
Topological domain14 – 454441Virion surface Potential
Region21 – 7555Hypervariable stalk region By similarity
Region76 – 454379Head of neuraminidase By similarity

Sites

Active site1361 Potential
Active site2621 Potential
Active site3871 Potential
Metal binding2791Calcium; via carbonyl oxygen By similarity
Metal binding2831Calcium; via carbonyl oxygen By similarity
Metal binding3091Calcium By similarity
Binding site1031Substrate Potential
Binding site2781Substrate Potential
Binding site3531Substrate Potential

Amino acid modifications

Glycosylation431N-linked (GlcNAc...); by host Potential
Glycosylation481N-linked (GlcNAc...); by host Potential
Glycosylation531N-linked (GlcNAc...); by host Potential
Glycosylation731N-linked (GlcNAc...); by host Potential
Glycosylation1311N-linked (GlcNAc...); by host Potential
Glycosylation2201N-linked (GlcNAc...); by host Potential
Disulfide bond77 ↔ 402 By similarity
Disulfide bond109 ↔ 114 By similarity
Disulfide bond169 ↔ 216 By similarity
Disulfide bond218 ↔ 223 By similarity
Disulfide bond264 ↔ 277 By similarity
Disulfide bond266 ↔ 275 By similarity
Disulfide bond406 ↔ 431 By similarity

Experimental info

Non-terminal residue11

Sequences

Sequence LengthMass (Da)Tools
Q6DPI6 [UniParc].

Last modified July 22, 2008. Version 2.
Checksum: 09163590DFA4E0F0

FASTA45449,799
        10         20         30         40         50         60 
VIGIVSLMLQ IGNIISIWVS HSIQTGNQHQ AEPCIQSIIT YENNTWVNQT YVNISNTNFL 

        70         80         90        100        110        120 
TEKTVASVTL AGNSSLCPIS GWAVYSKDNG IRIGSKGDVF VIREPFISCS HLECRTFFLT 

       130        140        150        160        170        180 
QGALLNDKHS NGTVKDRSPH RTLMSCPVGE APSPYNSRFE SVAWSASACH DGTNWLTIGI 

       190        200        210        220        230        240 
SGPDNGAVAV LKYNGIITDT IKSWRNNILR TQESECACVN GSCFTVMTDG PSNGQASYKI 

       250        260        270        280        290        300 
FRIEKGKVVK SVELNAPNYH YEECSCYPDA GEITCVCRDN WHGSNRPWVS FNQNLEYQIG 

       310        320        330        340        350        360 
YICSGIFGDN PRPNDGTGSC GPVSSNGAYG IKGFSYKYGN GVWIGRTKST NSRSGFEMIW 

       370        380        390        400        410        420 
DPNGWTGTDS NFSVKQDIVA ITDWSGYSGS FVQHPELTGL DCIRPCFWVE LIRGRPKEST 

       430        440        450 
IWTSGSSISF CGVNSDTVGW SWPDGAELPF TIDK 

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Cross-references

Sequence databases

EMBL
GenBank
DDBJ
AY651473 Genomic RNA. Translation: AAT73355.2.

3D structure databases

ProteinModelPortalQ6DPI6.
SMRQ6DPI6. Positions 68-452.
ModBaseSearch...
MobiDBSearch...

Protein family/group databases

CAZyGH34. Glycoside Hydrolase Family 34.

Protocols and materials databases

StructuralBiologyKnowledgebaseSearch...

Family and domain databases

Gene3D2.120.10.10. 1 hit.
InterProIPR001860. Glyco_hydro_34.
IPR011040. Sialidases.
[Graphical view]
PfamPF00064. Neur. 1 hit.
[Graphical view]
SUPFAMSSF50939. SSF50939. 1 hit.
ProtoNetSearch...

Entry information

Entry nameNRAM_I02A7
AccessionPrimary (citable) accession number: Q6DPI6
Entry history
Integrated into UniProtKB/Swiss-Prot: November 13, 2007
Last sequence update: July 22, 2008
Last modified: February 19, 2014
This is version 55 of the entry and version 2 of the sequence. [Complete history]
Entry statusReviewed (UniProtKB/Swiss-Prot)
Annotation programViral Protein Annotation Program

Relevant documents

SIMILARITY comments

Index of protein domains and families

Glycosyl hydrolases

Classification of glycosyl hydrolase families and list of entries