ID   Q9YTC2_9INFA            Unreviewed;       566 AA.
AC   Q9YTC2;
DT   01-MAY-1999, integrated into UniProtKB/TrEMBL.
DT   01-MAY-1999, sequence version 1.
DT   08-NOV-2023, entry version 128.
DE   RecName: Full=Hemagglutinin {ECO:0000256|HAMAP-Rule:MF_04072};
DE   Contains:
DE     RecName: Full=Hemagglutinin HA1 chain {ECO:0000256|HAMAP-Rule:MF_04072};
DE   Contains:
DE     RecName: Full=Hemagglutinin HA2 chain {ECO:0000256|HAMAP-Rule:MF_04072};
GN   Name=HA {ECO:0000256|HAMAP-Rule:MF_04072};
OS   Influenza A virus (A/swine/Scotland/410440/94(H1N2)).
OC   Viruses; Riboviria; Orthornavirae; Negarnaviricota; Polyploviricotina;
OC   Insthoviricetes; Articulavirales; Orthomyxoviridae; Alphainfluenzavirus;
OC   Alphainfluenzavirus influenzae; Influenza A virus.
OX   NCBI_TaxID=83206 {ECO:0000313|EMBL:AAD05215.1};
RN   [1] {ECO:0000313|EMBL:AAD05215.1}
RP   NUCLEOTIDE SEQUENCE.
RC   STRAIN=A/swine/Scotland/410440/94 {ECO:0000313|EMBL:AAD05215.1};
RX   PubMed=9880008;
RA   Brown I.H., Harris P.A., McCauley J.W., Alexander D.J.;
RT   "Multiple genetic reassortment of avian and human influenza A viruses in
RT   European pigs, resulting in the emergence of an H1N2 virus of novel
RT   genotype.";
RL   J. Gen. Virol. 79:0-0(1998).
RN   [2] {ECO:0000313|EMBL:AAD05215.1}
RP   NUCLEOTIDE SEQUENCE.
RC   STRAIN=A/swine/Scotland/410440/94 {ECO:0000313|EMBL:AAD05215.1};
RA   Brown I.H.;
RL   Submitted (AUG-1998) to the EMBL/GenBank/DDBJ databases.
RN   [3] {ECO:0007829|PDB:2KXA}
RP   STRUCTURE BY NMR OF 345-367.
RX   PubMed=20534508; DOI=10.1073/pnas.1006142107;
RA   Lorieau J.L., Louis J.M., Bax A.;
RT   "The complete influenza hemagglutinin fusion domain adopts a tight helical
RT   hairpin arrangement at the lipid:water interface.";
RL   Proc. Natl. Acad. Sci. U.S.A. 107:11341-11346(2010).
CC   -!- FUNCTION: Binds to sialic acid-containing receptors on the cell
CC       surface, bringing about the attachment of the virus particle to the
CC       cell. This attachment induces virion internalization either through
CC       clathrin-dependent endocytosis or through clathrin- and caveolin-
CC       independent pathway. Plays a major role in the determination of host
CC       range restriction and virulence. Class I viral fusion protein.
CC       Responsible for penetration of the virus into the cell cytoplasm by
CC       mediating the fusion of the membrane of the endocytosed virus particle
CC       with the endosomal membrane. Low pH in endosomes induces an
CC       irreversible conformational change in HA2, releasing the fusion
CC       hydrophobic peptide. Several trimers are required to form a competent
CC       fusion pore. {ECO:0000256|HAMAP-Rule:MF_04072}.
CC   -!- FUNCTION: Binds to sialic acid-containing receptors on the cell
CC       surface, bringing about the attachment of the virus particle to the
CC       cell. This attachment induces virion internalization of about two third
CC       of the virus particles through clathrin-dependent endocytosis and about
CC       one third through a clathrin- and caveolin-independent pathway. Plays a
CC       major role in the determination of host range restriction and
CC       virulence. Class I viral fusion protein. Responsible for penetration of
CC       the virus into the cell cytoplasm by mediating the fusion of the
CC       membrane of the endocytosed virus particle with the endosomal membrane.
CC       Low pH in endosomes induces an irreversible conformational change in
CC       HA2, releasing the fusion hydrophobic peptide. Several trimers are
CC       required to form a competent fusion pore.
CC       {ECO:0000256|RuleBase:RU003324}.
CC   -!- SUBUNIT: Homotrimer of disulfide-linked HA1-HA2. {ECO:0000256|HAMAP-
CC       Rule:MF_04072, ECO:0000256|RuleBase:RU003324}.
CC   -!- SUBCELLULAR LOCATION: Apical cell membrane
CC       {ECO:0000256|ARBA:ARBA00004247}; Single-pass type I membrane protein
CC       {ECO:0000256|ARBA:ARBA00004247}. Cell membrane
CC       {ECO:0000256|ARBA:ARBA00004251}; Single-pass type I membrane protein
CC       {ECO:0000256|ARBA:ARBA00004251}. Host apical cell membrane
CC       {ECO:0000256|ARBA:ARBA00004310, ECO:0000256|HAMAP-Rule:MF_04072};
CC       Single-pass type I membrane protein {ECO:0000256|ARBA:ARBA00004310,
CC       ECO:0000256|HAMAP-Rule:MF_04072}. Membrane
CC       {ECO:0000256|ARBA:ARBA00004479}; Single-pass type I membrane protein
CC       {ECO:0000256|ARBA:ARBA00004479}. Virion membrane {ECO:0000256|HAMAP-
CC       Rule:MF_04072}; Single-pass type I membrane protein {ECO:0000256|HAMAP-
CC       Rule:MF_04072}. Note=Targeted to the apical plasma membrane in
CC       epithelial polarized cells through a signal present in the
CC       transmembrane domain. Associated with glycosphingolipid- and
CC       cholesterol-enriched detergent-resistant lipid rafts.
CC       {ECO:0000256|HAMAP-Rule:MF_04072}.
CC   -!- PTM: In natural infection, inactive HA is matured into HA1 and HA2
CC       outside the cell by one or more trypsin-like, arginine-specific
CC       endoprotease secreted by the bronchial epithelial cells. One identified
CC       protease that may be involved in this process is secreted in lungs by
CC       club cells. {ECO:0000256|HAMAP-Rule:MF_04072}.
CC   -!- PTM: Palmitoylated. {ECO:0000256|HAMAP-Rule:MF_04072}.
CC   -!- SIMILARITY: Belongs to the influenza viruses hemagglutinin family.
CC       {ECO:0000256|ARBA:ARBA00006321, ECO:0000256|HAMAP-Rule:MF_04072,
CC       ECO:0000256|RuleBase:RU003324}.
CC   -!- CAUTION: Lacks conserved residue(s) required for the propagation of
CC       feature annotation. {ECO:0000256|HAMAP-Rule:MF_04072}.
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DR   EMBL; AF085413; AAD05215.1; -; mRNA.
DR   PDB; 2KXA; NMR; -; A=345-367.
DR   PDBsum; 2KXA; -.
DR   SMR; Q9YTC2; -.
DR   EvolutionaryTrace; Q9YTC2; -.
DR   GO; GO:0016324; C:apical plasma membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0020002; C:host cell plasma membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0019031; C:viral envelope; IEA:UniProtKB-UniRule.
DR   GO; GO:0055036; C:virion membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0046789; F:host cell surface receptor binding; IEA:UniProtKB-UniRule.
DR   GO; GO:0075512; P:clathrin-dependent endocytosis of virus by host cell; IEA:UniProtKB-UniRule.
DR   GO; GO:0039654; P:fusion of virus membrane with host endosome membrane; IEA:UniProtKB-UniRule.
DR   GO; GO:0019064; P:fusion of virus membrane with host plasma membrane; IEA:InterPro.
DR   GO; GO:0046761; P:viral budding from plasma membrane; IEA:UniProtKB-UniRule.
DR   GO; GO:0019062; P:virion attachment to host cell; IEA:UniProtKB-KW.
DR   Gene3D; 3.90.20.10; -; 1.
DR   Gene3D; 3.90.209.20; -; 1.
DR   Gene3D; 2.10.77.10; Hemagglutinin Chain A, Domain 2; 1.
DR   HAMAP; MF_04072; INFV_HEMA; 1.
DR   InterPro; IPR008980; Capsid_hemagglutn.
DR   InterPro; IPR013828; Hemagglutn_HA1_a/b_dom_sf.
DR   InterPro; IPR000149; Hemagglutn_influenz_A.
DR   InterPro; IPR001364; Hemagglutn_influenz_A/B.
DR   Pfam; PF00509; Hemagglutinin; 1.
DR   PRINTS; PR00330; HEMAGGLUTN1.
DR   PRINTS; PR00329; HEMAGGLUTN12.
DR   SUPFAM; SSF58064; Influenza hemagglutinin (stalk); 1.
DR   SUPFAM; SSF49818; Viral protein domain; 1.
PE   1: Evidence at protein level;
KW   3D-structure {ECO:0007829|PDB:2KXA};
KW   Clathrin- and caveolin-independent endocytosis of virus by host
KW   {ECO:0000256|ARBA:ARBA00023261, ECO:0000256|HAMAP-Rule:MF_04072};
KW   Clathrin-mediated endocytosis of virus by host
KW   {ECO:0000256|ARBA:ARBA00022570, ECO:0000256|HAMAP-Rule:MF_04072};
KW   Disulfide bond {ECO:0000256|ARBA:ARBA00023157, ECO:0000256|HAMAP-
KW   Rule:MF_04072};
KW   Fusion of virus membrane with host endosomal membrane
KW   {ECO:0000256|ARBA:ARBA00022510, ECO:0000256|HAMAP-Rule:MF_04072};
KW   Fusion of virus membrane with host membrane {ECO:0000256|ARBA:ARBA00022506,
KW   ECO:0000256|HAMAP-Rule:MF_04072};
KW   Glycoprotein {ECO:0000256|ARBA:ARBA00023180, ECO:0000256|HAMAP-
KW   Rule:MF_04072};
KW   Hemagglutinin {ECO:0000256|ARBA:ARBA00022546, ECO:0000256|HAMAP-
KW   Rule:MF_04072};
KW   Host cell membrane {ECO:0000256|ARBA:ARBA00022511, ECO:0000256|HAMAP-
KW   Rule:MF_04072};
KW   Host membrane {ECO:0000256|ARBA:ARBA00022870, ECO:0000256|HAMAP-
KW   Rule:MF_04072};
KW   Host-virus interaction {ECO:0000256|ARBA:ARBA00022581, ECO:0000256|HAMAP-
KW   Rule:MF_04072};
KW   Lipoprotein {ECO:0000256|ARBA:ARBA00023288, ECO:0000256|HAMAP-
KW   Rule:MF_04072};
KW   Membrane {ECO:0000256|ARBA:ARBA00023136, ECO:0000256|HAMAP-Rule:MF_04072};
KW   Palmitate {ECO:0000256|ARBA:ARBA00023139, ECO:0000256|HAMAP-Rule:MF_04072};
KW   Signal {ECO:0000256|HAMAP-Rule:MF_04072};
KW   Transmembrane {ECO:0000256|HAMAP-Rule:MF_04072};
KW   Transmembrane helix {ECO:0000256|HAMAP-Rule:MF_04072};
KW   Viral attachment to host cell {ECO:0000256|ARBA:ARBA00022804,
KW   ECO:0000256|HAMAP-Rule:MF_04072};
KW   Viral envelope protein {ECO:0000256|ARBA:ARBA00022879, ECO:0000256|HAMAP-
KW   Rule:MF_04072};
KW   Viral penetration into host cytoplasm {ECO:0000256|ARBA:ARBA00022595,
KW   ECO:0000256|HAMAP-Rule:MF_04072};
KW   Virion {ECO:0000256|ARBA:ARBA00022844, ECO:0000256|HAMAP-Rule:MF_04072};
KW   Virus endocytosis by host {ECO:0000256|ARBA:ARBA00022890,
KW   ECO:0000256|HAMAP-Rule:MF_04072};
KW   Virus entry into host cell {ECO:0000256|ARBA:ARBA00023296,
KW   ECO:0000256|HAMAP-Rule:MF_04072}.
FT   CHAIN           345..566
FT                   /note="Hemagglutinin HA2 chain"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_04072"
FT                   /id="PRO_5023309943"
FT   TRANSMEM        531..553
FT                   /note="Helical"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_04072"
FT   SITE            344..345
FT                   /note="Cleavage; by host"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_04072"
FT   LIPID           555
FT                   /note="S-palmitoyl cysteine; by host"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_04072"
FT   LIPID           562
FT                   /note="S-palmitoyl cysteine; by host"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_04072"
FT   LIPID           565
FT                   /note="S-palmitoyl cysteine; by host"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_04072"
FT   DISULFID        72..84
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_04072"
FT   DISULFID        296..320
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_04072"
FT   DISULFID        488..492
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_04072"
SQ   SEQUENCE   566 AA;  63833 MW;  2270269582E8969A CRC64;
     MKEKLLVLLC ALSATDADTI CIGYHANNST DTVDTVLEKN VTVTHSVNLL EDSHNGKLCR
     LKGIAPLQLG KCSIAGWILG NPECELLFSK KSWSYIAETP NSENGICYPG YFSDYEELRE
     QLSSVSSFER FEIFPKESSW PKHSVNKGVT KSCSHKGKSS FYRNLLWLTE KNGSYPNLSK
     SYVNNKEKEV LVLWGVHHPS NIENQKTIYR KETAYVSVVS SHYNRRFTPE ITRRPKVRDQ
     EGRINYYWTL LEPGDTIIFE ANGNLIAPWY RFALSRGFGS GIIISNASMD ECDAKCQTPQ
     GAINSSLPFQ NVHPVTIGEC PKYVRSKKLR MVTGLRNIPS IQSRGLFGAI AGFIEGGWTG
     MIDGWYGYHH QNEQGSGYAA DQKSTQNAIN GITNKVNSVI EKMNTQFTAV GKEFNKLEKR
     IENLNKKVDD GFLDIWTYNA ELLVLLENER TLDFHDSNVK TLYEKVKNQL KNNAKEIGNG
     CFEFYHKCNN ECMESVKNGT YDYPKYSEES KLNREKIDGV KLESMGVYQI LAIYSTVASS
     LVLLVSLGAA SFWMCSNGSL QCRICI
//