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P26562 (HEMA_I76A4) Reviewed, UniProtKB/Swiss-Prot

Last modified February 19, 2014. Version 94. Feed History...

Clusters with 100%, 90%, 50% identity | Documents (2) | Third-party data text xml rdf/xml gff fasta
to top of pageNames·Attributes·General annotation·Ontologies·Sequence annotation·Sequences·References·Cross-refs·Entry info·DocumentsCustomize order

Names and origin

Protein namesRecommended name:
Hemagglutinin

Cleaved into the following 2 chains:

  1. Hemagglutinin HA1 chain
  2. Hemagglutinin HA2 chain
Gene names
Name:HA
OrganismInfluenza A virus (strain A/Duck/Alberta/35/1976 H1N1)
Taxonomic identifier352520 [NCBI]
Taxonomic lineageVirusesssRNA negative-strand virusesOrthomyxoviridaeInfluenzavirus A
Virus hostAves [TaxID: 8782]
Homo sapiens (Human) [TaxID: 9606]
Sus scrofa (Pig) [TaxID: 9823]

Protein attributes

Sequence length566 AA.
Sequence statusComplete.
Sequence processingThe displayed sequence is further processed into a mature form.
Protein existenceEvidence at protein level

General annotation (Comments)

Function

Binds to sialic acid-containing receptors on the cell surface, bringing about the attachment of the virus particle to the cell. This attachment induces virion internalization of about two third of the virus particles through clathrin-dependent endocytosis and about one third through a clathrin- and caveolin-independent pathway. Plays a major role in the determination of host range restriction and virulence. Class I viral fusion protein. Responsible for penetration of the virus into the cell cytoplasm by mediating the fusion of the membrane of the endocytosed virus particle with the endosomal membrane. Low pH in endosomes induces an irreversible conformational change in HA2, releasing the fusion hydrophobic peptide. Several trimers are required to form a competent fusion pore.

Subunit structure

Homotrimer of disulfide-linked HA1-HA2.

Subcellular location

Virion membrane; Single-pass type I membrane protein Potential. Host apical cell membrane; Single-pass type I membrane protein. Note: Targeted to the apical plasma membrane in epithelial polarized cells through a signal present in the transmembrane domain. Associated with glycosphingolipid- and cholesterol-enriched detergent-resistant lipid rafts.

Post-translational modification

In natural infection, inactive HA is matured into HA1 and HA2 outside the cell by one or more trypsin-like, arginine-specific endoprotease secreted by the bronchial epithelial cells. One identified protease that may be involved in this process is secreted in lungs by Clara cells By similarity.

Palmitoylated By similarity.

Miscellaneous

Major glycoprotein, comprises over 80% of the envelope proteins present in virus particle.

The extent of infection into host organism is determined by HA. Influenza viruses bud from the apical surface of polarized epithelial cells (e.g. bronchial epithelial cells) into lumen of lungs and are therefore usually pneumotropic. The reason is that HA is cleaved by tryptase clara which is restricted to lungs. However, HAs of H5 and H7 pantropic avian viruses subtypes can be cleaved by furin and subtilisin-type enzymes, allowing the virus to grow in other organs than lungs.

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 influenza viruses hemagglutinin family.

Sequence annotation (Features)

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifier

Molecule processing

Signal peptide1 – 1717 Potential
Chain18 – 343326Hemagglutinin HA1 chain
PRO_0000038910
Chain345 – 566222Hemagglutinin HA2 chain
PRO_0000038911

Regions

Topological domain18 – 529512Extracellular Potential
Transmembrane530 – 55021Helical; Potential
Topological domain551 – 56616Cytoplasmic Potential

Sites

Site344 – 3452Cleavage; by host By similarity

Amino acid modifications

Lipidation5551S-palmitoyl cysteine; by host By similarity
Lipidation5621S-palmitoyl cysteine; by host By similarity
Lipidation5651S-palmitoyl cysteine; by host By similarity
Glycosylation271N-linked (GlcNAc...); by host Potential
Glycosylation281N-linked (GlcNAc...); by host Potential
Glycosylation401N-linked (GlcNAc...); by host Potential
Glycosylation1041N-linked (GlcNAc...); by host Potential
Glycosylation3041N-linked (GlcNAc...); by host Potential
Glycosylation4981N-linked (GlcNAc...); by host Potential
Disulfide bond21 ↔ 481Interchain (between HA1 and HA2 chains) By similarity
Disulfide bond59 ↔ 292 By similarity
Disulfide bond72 ↔ 84 By similarity
Disulfide bond107 ↔ 153 By similarity
Disulfide bond296 ↔ 320 By similarity
Disulfide bond488 ↔ 492 By similarity

Experimental info

Sequence conflict651A → P in AAB52910. Ref.2
Sequence conflict1251I → V in AAB52910. Ref.2
Sequence conflict2361E → K in AAB52910. Ref.2

Secondary structure

........................................................................ 566
Helix Strand Turn

Details...

Sequences

Sequence LengthMass (Da)Tools
P26562 [UniParc].

Last modified February 1, 1996. Version 2.
Checksum: 9B7ADCA0E9BCA819

FASTA56663,072
        10         20         30         40         50         60 
MEAKLFVLFC TFTVLKADTI CVGYHANNST DTVDTVLEKN VTVTHSVNLL EDSHNGKLCS 

        70         80         90        100        110        120 
LNGIAPLQLG KCNVAGWLLG NPECDLLLTA NSWSYIIETS NSENGTCYPG EFIDYEELRE 

       130        140        150        160        170        180 
QLSSISSFEK FEIFPKASSW PNHETTKGVT AACSYSGASS FYRNLLWITK KGTSYPKLSK 

       190        200        210        220        230        240 
SYTNNKGKEV LVLWGVHHPP SVSEQQSLYQ NADAYVSVGS SKYNRRFAPE IAARPEVRGQ 

       250        260        270        280        290        300 
AGRMNYYWTL LDQGDTITFE ATGNLIAPWY AFALNKGSDS GIITSDAPVH NCDTRCQTPH 

       310        320        330        340        350        360 
GALNSSLPFQ NVHPITIGEC PKYVKSTKLR MATGLRNVPS IQSRGLFGAI AGFIEGGWTG 

       370        380        390        400        410        420 
MIDGWYGYHH QNEQGSGYAA DQKSTQNAID GITSKVNSVI EKMNTQFTAV GKEFNNLERR 

       430        440        450        460        470        480 
IENLNKKVDD GFLDVWTYNA ELLVLLENER TLDFHDSNVR NLYEKVKSQL RNNAKEIGNG 

       490        500        510        520        530        540 
CFEFYHKCDD ECMESVKNGT YDYPKYSEES KLNREEIDGV KLESMGVYQI LAIYSTVASS 

       550        560 
LVLLVSWGAI SFWMCSNGSL QCRICI 

« Hide

References

[1]"Molecular analysis of the haemagglutinin gene of an avian H1N1 influenza virus."
Austin F.J., Kawaoka Y., Webster R.G.
J. Gen. Virol. 71:2471-2474(1990) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC RNA].
[2]"Emergence of avian H1N1 influenza viruses in pigs in China."
Guan Y., Shortridge K.F., Krauss S., Li P.H., Kawaoka Y., Webster R.G.
J. Virol. 70:8041-8046(1996) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [MRNA] OF 18-344.
+Additional computationally mapped references.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ
D10477 Genomic RNA. Translation: BAA01280.1.
U47310 mRNA. Translation: AAB52910.1.
PIRHMIVD1. A36257.

3D structure databases

PDBe
RCSB PDB
PDBj
EntryMethodResolution (Å)ChainPositionsPDBsum
2WRHX-ray3.00H/J/L18-343[»]
I/K/M345-566[»]
ProteinModelPortalP26562.
SMRP26562. Positions 18-519.
ModBaseSearch...
MobiDBSearch...

Protocols and materials databases

StructuralBiologyKnowledgebaseSearch...

Family and domain databases

Gene3D2.10.77.10. 1 hit.
3.90.20.10. 1 hit.
3.90.209.20. 1 hit.
InterProIPR008980. Capsid_hemagglutn.
IPR013828. Hemagglutn_HA1_a/b_dom.
IPR013827. Hemagglutn_HA1_b-rbn_dom.
IPR000149. Hemagglutn_influenz_A.
IPR001364. Hemagglutn_influenz_A/B.
IPR013829. Hemagglutn_stalk.
[Graphical view]
PfamPF00509. Hemagglutinin. 1 hit.
[Graphical view]
PRINTSPR00330. HEMAGGLUTN1.
PR00329. HEMAGGLUTN12.
SUPFAMSSF49818. SSF49818. 1 hit.
ProtoNetSearch...

Other

EvolutionaryTraceP26562.

Entry information

Entry nameHEMA_I76A4
AccessionPrimary (citable) accession number: P26562
Secondary accession number(s): O09652
Entry history
Integrated into UniProtKB/Swiss-Prot: August 1, 1992
Last sequence update: February 1, 1996
Last modified: February 19, 2014
This is version 94 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

PDB cross-references

Index of Protein Data Bank (PDB) cross-references