ID   AP3A_SARS               Reviewed;         274 AA.
AC   P59632; Q7T6R6; Q7TA10; Q7TA18; Q7TFB0; Q7TLD0; Q80BV5;
DT   23-APR-2003, integrated into UniProtKB/Swiss-Prot.
DT   23-APR-2003, sequence version 1.
DT   24-JAN-2024, entry version 113.
DE   RecName: Full=ORF3a protein;
DE   AltName: Full=Accessory protein 3a;
DE   AltName: Full=Protein 3a;
DE   AltName: Full=Protein U274;
DE   AltName: Full=Protein X1;
GN   ORFNames=3a;
OS   Severe acute respiratory syndrome coronavirus (SARS-CoV).
OC   Viruses; Riboviria; Orthornavirae; Pisuviricota; Pisoniviricetes;
OC   Nidovirales; Cornidovirineae; Coronaviridae; Orthocoronavirinae;
OC   Betacoronavirus; Sarbecovirus.
OX   NCBI_TaxID=694009;
OH   NCBI_TaxID=9606; Homo sapiens (Human).
OH   NCBI_TaxID=9675; Paguma larvata (Masked palm civet).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RC   STRAIN=Isolate Urbani;
RX   PubMed=12730500; DOI=10.1126/science.1085952;
RA   Rota P.A., Oberste M.S., Monroe S.S., Nix W.A., Campagnoli R.,
RA   Icenogle J.P., Penaranda S., Bankamp B., Maher K., Chen M.-H., Tong S.,
RA   Tamin A., Lowe L., Frace M., DeRisi J.L., Chen Q., Wang D., Erdman D.D.,
RA   Peret T.C.T., Burns C., Ksiazek T.G., Rollin P.E., Sanchez A., Liffick S.,
RA   Holloway B., Limor J., McCaustland K., Olsen-Rasmussen M., Fouchier R.,
RA   Guenther S., Osterhaus A.D.M.E., Drosten C., Pallansch M.A., Anderson L.J.,
RA   Bellini W.J.;
RT   "Characterization of a novel coronavirus associated with severe acute
RT   respiratory syndrome.";
RL   Science 300:1394-1399(2003).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RC   STRAIN=Isolate Tor2;
RX   PubMed=12730501; DOI=10.1126/science.1085953;
RA   Marra M.A., Jones S.J.M., Astell C.R., Holt R.A., Brooks-Wilson A.,
RA   Butterfield Y.S.N., Khattra J., Asano J.K., Barber S.A., Chan S.Y.,
RA   Cloutier A., Coughlin S.M., Freeman D., Girn N., Griffith O.L., Leach S.R.,
RA   Mayo M., McDonald H., Montgomery S.B., Pandoh P.K., Petrescu A.S.,
RA   Robertson A.G., Schein J.E., Siddiqui A., Smailus D.E., Stott J.M.,
RA   Yang G.S., Plummer F., Andonov A., Artsob H., Bastien N., Bernard K.,
RA   Booth T.F., Bowness D., Czub M., Drebot M., Fernando L., Flick R.,
RA   Garbutt M., Gray M., Grolla A., Jones S., Feldmann H., Meyers A.,
RA   Kabani A., Li Y., Normand S., Stroher U., Tipples G.A., Tyler S.,
RA   Vogrig R., Ward D., Watson B., Brunham R.C., Krajden M., Petric M.,
RA   Skowronski D.M., Upton C., Roper R.L.;
RT   "The genome sequence of the SARS-associated coronavirus.";
RL   Science 300:1399-1404(2003).
RN   [3]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RC   STRAIN=Isolate CUHK-Su10, and Isolate CUHK-W1;
RX   PubMed=12853594; DOI=10.1056/nejm200307103490216;
RA   Tsui S.K.W., Chim S.S.C., Lo Y.M.D.;
RT   "Coronavirus genomic-sequence variations and the epidemiology of the severe
RT   acute respiratory syndrome.";
RL   N. Engl. J. Med. 349:187-188(2003).
RN   [4]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RC   STRAIN=Isolate HKU-39849;
RX   PubMed=12876307; DOI=10.1177/15353702-0322807-13;
RA   Zeng F.Y., Chan C.W., Chan M.N., Chen J.D., Chow K.Y.C., Hon C.C.C.,
RA   Hui R.K.H., Li J., Li V.Y.Y., Wang C.Y., Wang P.Y., Guan Y., Zheng B.,
RA   Poon L.L.M., Chan K.H., Yuen K.Y., Peiris J.S.M., Leung F.C.;
RT   "The complete genome sequence of severe acute respiratory syndrome
RT   coronavirus strain HKU-39849 (HK-39).";
RL   Exp. Biol. Med. 228:866-873(2003).
RN   [5]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RC   STRAIN=Isolate BJ01, Isolate BJ02, Isolate BJ03, Isolate BJ04, and
RC   Isolate GD01;
RA   Qin E., Zhu Q., Yu M., Fan B., Chang G., Si B., Yang B., Peng W., Jiang T.,
RA   Liu B., Deng Y., Liu H., Zhang Y., Wang C., Li Y., Gan Y., Li X., Lu F.,
RA   Tan G., Yang R., Cao W.S., Wang J., Chen W., Cong L., Deng Y., Dong W.,
RA   Han Y., Hu W., Lei M., Li C., Li G., Li G., Li H., Li S., Li S., Li W.,
RA   Li W., Lin W., Liu J., Liu Z., Lu H., Ni P., Qi Q., Sun Y., Tang L.,
RA   Tong Z., Wang J., Wang X., Wu Q., Xi Y., Xu Z., Yang L., Ye C., Ye J.,
RA   Zhang B., Zhang F., Zhang J., Zhang X., Zhou J., Yang H.;
RL   Submitted (APR-2003) to the EMBL/GenBank/DDBJ databases.
RN   [6]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RC   STRAIN=Isolate TW1;
RA   Yeh S.-H., Kao C.-L., Tsai C.-Y., Liu C.-J., Chen D.-S., Chen P.-J.;
RT   "The complete genome of SARS coronavirus clone TW1.";
RL   Submitted (MAY-2003) to the EMBL/GenBank/DDBJ databases.
RN   [7]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RC   STRAIN=Isolate FRA;
RA   Eickmann M., Becker S., Klenk H.-D., Doerr H.W., Stadler K., Censini S.,
RA   Guidotti S., Masignani V., Scarselli M., Mora M., Donati C., Han J.,
RA   Song H.C., Abrignani S., Covacci A., Rappuoli R.;
RT   "SARS virus is a close relative of type II coronaviruses.";
RL   Submitted (MAY-2003) to the EMBL/GenBank/DDBJ databases.
RN   [8]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RC   STRAIN=Isolate Frankfurt 1;
RA   Thiel V., Hertzig T., Putics A., Ivanov K.A., Schelle B., Bayer S.,
RA   Scheiner B., Weinand H., Weissbrich B., Ziebuhr J.;
RL   Submitted (MAY-2003) to the EMBL/GenBank/DDBJ databases.
RN   [9]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RC   STRAIN=Isolate Taiwan TC1, Isolate Taiwan TC2, and Isolate Taiwan TC3;
RA   Chang J.-G.C., Lin T.-H., Chen C.-M., Lin C.-S., Chan W.-L., Shih M.-C.;
RL   Submitted (JUL-2003) to the EMBL/GenBank/DDBJ databases.
RN   [10]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RC   STRAIN=Isolate TWH, Isolate TWJ, Isolate TWK, Isolate TWS, and Isolate TWY;
RA   Shu H.Y., Wu K.M., Tsai S.F.;
RT   "The complete genome of SARS coronavirus TWH.";
RL   Submitted (JUL-2003) to the EMBL/GenBank/DDBJ databases.
RN   [11]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RC   STRAIN=Isolate HSR 1;
RA   Canducci F., Clementi M., Poli G., Vicenzi E.;
RL   Submitted (JUL-2003) to the EMBL/GenBank/DDBJ databases.
RN   [12]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RC   STRAIN=Isolate AS;
RA   Balotta C., Corvasce S., Violin M., Galli M., Moroni M., Vigevani G.M.,
RA   Ruan Y.J., Salemi M.;
RL   Submitted (OCT-2003) to the EMBL/GenBank/DDBJ databases.
RN   [13]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RC   STRAIN=Isolate Shanghai QXC1;
RA   Yuan Z., Zhang X., Hu Y., Lan S., Wang H., Zhou Z., Wen Y.;
RT   "Analysis of SARS coronavirus genome in Shanghai isolates.";
RL   Submitted (JAN-2004) to the EMBL/GenBank/DDBJ databases.
RN   [14]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA] OF 1-125.
RC   STRAIN=Isolate Shanghai LY;
RA   Yuan Z., Zhang X., Hu Y., Lan S., Wang H., Zhou Z., Wen Y.;
RL   Submitted (JUN-2003) to the EMBL/GenBank/DDBJ databases.
RN   [15]
RP   IDENTIFICATION.
RX   PubMed=15135062; DOI=10.1016/j.febslet.2004.03.086;
RA   Yu C.-J., Chen Y.-C., Hsiao C.-H., Kuo T.-C., Chang S.C., Lu C.-Y.,
RA   Wei W.-C., Lee C.-H., Huang L.-M., Chang M.-F., Ho H.-N., Lee F.-J.S.;
RT   "Identification of a novel protein 3a from severe acute respiratory
RT   syndrome coronavirus.";
RL   FEBS Lett. 565:111-116(2004).
RN   [16]
RP   SUBCELLULAR LOCATION, TOPOLOGY, AND INTERACTION WITH M PROTEIN; E PROTEIN;
RP   SPIKE GLYCOPROTEIN AND ACCESSORY PROTEIN 7A.
RX   PubMed=15194747; DOI=10.1128/jvi.78.13.6723-6734.2004;
RA   Tan Y.-J., Teng E., Shen S., Tan T.H.P., Goh P.-Y., Fielding B.C.,
RA   Ooi E.-E., Tan H.-C., Lim S.G., Hong W.;
RT   "A novel severe acute respiratory syndrome coronavirus protein, U274, is
RT   transported to the cell surface and undergoes endocytosis.";
RL   J. Virol. 78:6723-6734(2004).
RN   [17]
RP   SUBCELLULAR LOCATION, AND INTERACTION WITH M AND E PROTEINS.
RX   PubMed=15763150; DOI=10.1016/j.virusres.2005.01.001;
RA   Yuan X., Li J., Shan Y., Yang Z., Zhao Z., Chen B., Yao Z., Dong B.,
RA   Wang S., Chen J., Cong Y.;
RT   "Subcellular localization and membrane association of SARS-CoV 3a
RT   protein.";
RL   Virus Res. 109:191-202(2005).
RN   [18]
RP   CHARACTERIZATION.
RX   PubMed=15781262; DOI=10.1016/j.bbrc.2005.02.153;
RA   Shen S., Lin P.S., Chao Y.C., Zhang A., Yang X., Lim S.G., Hong W.,
RA   Tan Y.J.;
RT   "The severe acute respiratory syndrome coronavirus 3a is a novel structural
RT   protein.";
RL   Biochem. Biophys. Res. Commun. 330:286-292(2005).
RN   [19]
RP   CHARACTERIZATION, AND SUBCELLULAR LOCATION.
RX   PubMed=15709039; DOI=10.1128/jvi.79.5.3182-3186.2005;
RA   Ito N., Mossel E.C., Narayanan K., Popov V.L., Huang C., Inoue T.,
RA   Peters C.J., Makino S.;
RT   "Severe acute respiratory syndrome coronavirus 3a protein is a viral
RT   structural protein.";
RL   J. Virol. 79:3182-3186(2005).
RN   [20]
RP   FUNCTION.
RX   PubMed=16014971; DOI=10.1128/jvi.79.15.10083-10087.2005;
RA   Tan Y.J., Tham P.Y., Chan D.Z., Chou C.-F., Shen S., Fielding B.C.,
RA   Tan T.H., Lim S.G., Hong W.;
RT   "The severe acute respiratory syndrome coronavirus 3a protein up-regulates
RT   expression of fibrinogen in lung epithelial cells.";
RL   J. Virol. 79:10083-10087(2005).
RN   [21]
RP   FUNCTION.
RX   PubMed=15958670; DOI=10.1099/vir.0.80813-0;
RA   Law P.T., Wong C.H., Au T.C., Chuck C.P., Kong S.K., Chan P.K., To K.F.,
RA   Lo A.W., Chan J.Y., Suen Y.K., Chan H.Y., Fung K.P., Waye M.M., Sung J.J.,
RA   Lo Y.M.D., Tsui S.K.W.;
RT   "The 3a protein of severe acute respiratory syndrome-associated coronavirus
RT   induces apoptosis in Vero E6 cells.";
RL   J. Gen. Virol. 86:1921-1930(2005).
RN   [22]
RP   GLYCOSYLATION, AND MUTAGENESIS OF SER-27; THR-28; THR-32 AND THR-34.
RX   PubMed=16474139; DOI=10.1128/jvi.80.5.2326-2336.2006;
RA   Oostra M., de Haan C.A., de Groot R.J., Rottier P.J.M.;
RT   "Glycosylation of the severe acute respiratory syndrome coronavirus triple-
RT   spanning membrane proteins 3a and M.";
RL   J. Virol. 80:2326-2336(2006).
RN   [23]
RP   SUBCELLULAR LOCATION.
RX   PubMed=16352545; DOI=10.1128/jvi.80.1.210-217.2006;
RA   Huang C., Narayanan K., Ito N., Peters C.J., Makino S.;
RT   "Severe acute respiratory syndrome coronavirus 3a protein is released in
RT   membranous structures from 3a protein-expressing cells and infected
RT   cells.";
RL   J. Virol. 80:210-217(2006).
RN   [24]
RP   FUNCTION, SUBUNIT, AND MUTAGENESIS OF CYS-81; CYS-117; CYS-121; CYS-127;
RP   CYS-130; CYS-133; CYS-148 AND CYS-157.
RX   PubMed=16894145; DOI=10.1073/pnas.0605402103;
RA   Lu W., Zheng B.-J., Xu K., Schwarz W., Du L., Wong C.K.L., Chen J.,
RA   Duan S., Deubel V., Sun B.;
RT   "Severe acute respiratory syndrome-associated coronavirus 3a protein forms
RT   an ion channel and modulates virus release.";
RL   Proc. Natl. Acad. Sci. U.S.A. 103:12540-12545(2006).
RN   [25]
RP   FUNCTION.
RX   PubMed=20020050; DOI=10.1371/journal.pone.0008342;
RA   Minakshi R., Padhan K., Rani M., Khan N., Ahmad F., Jameel S.;
RT   "The SARS Coronavirus 3a protein causes endoplasmic reticulum stress and
RT   induces ligand-independent downregulation of the type 1 interferon
RT   receptor.";
RL   PLoS ONE 4:E8342-E8342(2009).
CC   -!- FUNCTION: Forms homotetrameric potassium sensitive ion channels
CC       (viroporin) and may modulate virus release. Up-regulates expression of
CC       fibrinogen subunits FGA, FGB and FGG in host lung epithelial cells.
CC       Induces apoptosis in cell culture. Down-regulates the type 1 interferon
CC       receptor by inducing serine phosphorylation within the IFN alpha-
CC       receptor subunit 1 (IFNAR1) degradation motif and increasing IFNAR1
CC       ubiquitination. {ECO:0000269|PubMed:15958670,
CC       ECO:0000269|PubMed:16014971, ECO:0000269|PubMed:16894145,
CC       ECO:0000269|PubMed:20020050}.
CC   -!- SUBUNIT: Homotetramer composed of two homodimers linked non covalently.
CC       Interacts with M, S and E proteins. Also interacts with the accessory
CC       protein 7a. {ECO:0000269|PubMed:15194747, ECO:0000269|PubMed:15763150,
CC       ECO:0000269|PubMed:16894145}.
CC   -!- INTERACTION:
CC       P59632; P59632: 3a; NbExp=3; IntAct=EBI-15595051, EBI-15595051;
CC       P59632; P59596: M; NbExp=2; IntAct=EBI-15595051, EBI-25487824;
CC       P59632; PRO_0000037310 [P0C6X7]: rep; NbExp=2; IntAct=EBI-15595051, EBI-25474098;
CC       P59632; P33724: CAV1; Xeno; NbExp=5; IntAct=EBI-15595051, EBI-79998;
CC   -!- SUBCELLULAR LOCATION: Virion. Host Golgi apparatus membrane; Multi-pass
CC       membrane protein. Host cell membrane; Multi-pass membrane protein.
CC       Secreted. Host cytoplasm. Note=The cell surface expressed protein can
CC       undergo endocytosis. The protein is secreted in association with
CC       membranous structures.
CC   -!- DOMAIN: The second or the third transmembrane region are responsible
CC       for Golgi localization.
CC   -!- PTM: Exists in both O-glycosylated and non-glycosylated forms. The
CC       glycosylated form is associated with the virion.
CC       {ECO:0000269|PubMed:16474139}.
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DR   EMBL; AY278741; AAP13446.1; -; Genomic_RNA.
DR   EMBL; AY274119; AAP41038.1; -; Genomic_RNA.
DR   EMBL; AY282752; -; NOT_ANNOTATED_CDS; Genomic_RNA.
DR   EMBL; AY278554; AAP13568.1; -; Genomic_RNA.
DR   EMBL; AY278491; -; NOT_ANNOTATED_CDS; Genomic_RNA.
DR   EMBL; AY278487; -; NOT_ANNOTATED_CDS; Genomic_RNA.
DR   EMBL; AY278488; AAP30031.1; -; Genomic_RNA.
DR   EMBL; AY278489; AAP51228.1; -; Genomic_RNA.
DR   EMBL; AY278490; -; NOT_ANNOTATED_CDS; Genomic_RNA.
DR   EMBL; AY279354; -; NOT_ANNOTATED_CDS; Genomic_RNA.
DR   EMBL; AY291451; AAP37018.1; -; Genomic_RNA.
DR   EMBL; AY310120; AAP50486.1; -; Genomic_RNA.
DR   EMBL; AY291315; AAP33698.1; -; Genomic_RNA.
DR   EMBL; AY338174; AAQ01598.1; -; Genomic_RNA.
DR   EMBL; AY338175; AAQ01610.1; -; Genomic_RNA.
DR   EMBL; AY348314; AAP97883.1; -; Genomic_RNA.
DR   EMBL; AP006557; BAC81349.1; -; Genomic_RNA.
DR   EMBL; AP006558; BAC81363.1; -; Genomic_RNA.
DR   EMBL; AP006559; BAC81377.1; -; Genomic_RNA.
DR   EMBL; AP006560; BAC81391.1; -; Genomic_RNA.
DR   EMBL; AP006561; BAC81405.1; -; Genomic_RNA.
DR   EMBL; AY323977; AAP72975.1; -; Genomic_RNA.
DR   EMBL; AY427439; AAQ94061.1; -; Genomic_RNA.
DR   EMBL; AY463059; AAP82984.2; -; Genomic_RNA.
DR   EMBL; AY322207; AAP82969.1; -; Genomic_RNA.
DR   PDB; 8EQS; EM; 3.10 A; A/B=1-274.
DR   PDBsum; 8EQS; -.
DR   SMR; P59632; -.
DR   BioGRID; 4383917; 75.
DR   ComplexPortal; CPX-6095; SARS-CoV 3a complex.
DR   DIP; DIP-61251N; -.
DR   IntAct; P59632; 58.
DR   MINT; P59632; -.
DR   TCDB; 1.A.57.1.1; the human sars coronavirus viroporin (sars-vp) family.
DR   GlyGen; P59632; 4 sites.
DR   iPTMnet; P59632; -.
DR   OrthoDB; 30211at10239; -.
DR   Reactome; R-HSA-9678110; Attachment and Entry.
DR   Reactome; R-HSA-9679509; Virion Assembly and Release.
DR   Reactome; R-HSA-9683673; Maturation of protein 3a.
DR   Reactome; R-HSA-9683701; Translation of Structural Proteins.
DR   Reactome; R-HSA-9686347; Microbial modulation of RIPK1-mediated regulated necrosis.
DR   Reactome; R-HSA-9692913; SARS-CoV-1-mediated effects on programmed cell death.
DR   Reactome; R-HSA-9692916; SARS-CoV-1 activates/modulates innate immune responses.
DR   Reactome; R-HSA-9735871; SARS-CoV-1 targets host intracellular signalling and regulatory pathways.
DR   SIGNOR; P59632; -.
DR   Proteomes; UP000000354; Segment.
DR   Proteomes; UP000103670; Genome.
DR   Proteomes; UP000109640; Genome.
DR   Proteomes; UP000116947; Genome.
DR   Proteomes; UP000121636; Genome.
DR   Proteomes; UP000131569; Genome.
DR   Proteomes; UP000131955; Genome.
DR   Proteomes; UP000137377; Genome.
DR   Proteomes; UP000138690; Genome.
DR   Proteomes; UP000143093; Genome.
DR   Proteomes; UP000145651; Genome.
DR   Proteomes; UP000146108; Genome.
DR   Proteomes; UP000146181; Genome.
DR   Proteomes; UP000146296; Genome.
DR   Proteomes; UP000148194; Genome.
DR   Proteomes; UP000153467; Genome.
DR   Proteomes; UP000160648; Genome.
DR   Proteomes; UP000164441; Genome.
DR   Proteomes; UP000172416; Genome.
DR   GO; GO:0005576; C:extracellular region; TAS:Reactome.
DR   GO; GO:0044178; C:host cell Golgi membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0020002; C:host cell plasma membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0005886; C:plasma membrane; IDA:ComplexPortal.
DR   GO; GO:0055036; C:virion membrane; TAS:Reactome.
DR   GO; GO:0005891; C:voltage-gated calcium channel complex; ISO:ComplexPortal.
DR   GO; GO:0008076; C:voltage-gated potassium channel complex; IPI:ComplexPortal.
DR   GO; GO:0042802; F:identical protein binding; IPI:IntAct.
DR   GO; GO:0005216; F:monoatomic ion channel activity; IEA:UniProtKB-KW.
DR   GO; GO:0098662; P:inorganic cation transmembrane transport; IDA:ComplexPortal.
DR   GO; GO:0051259; P:protein complex oligomerization; IEA:UniProtKB-KW.
DR   GO; GO:0140886; P:suppression by virus of host interferon-mediated signaling pathway; IEA:UniProtKB-KW.
DR   GO; GO:0039502; P:suppression by virus of host type I interferon-mediated signaling pathway; IEA:UniProtKB-KW.
DR   GO; GO:0039707; P:virus-mediated pore formation in host cell membrane; IEA:UniProtKB-KW.
DR   CDD; cd21648; SARS-CoV-like_ORF3a; 1.
DR   InterPro; IPR046446; a/bCoV_VIROPORIN_3A-like_CD.
DR   InterPro; IPR046445; a/bCoV_VIROPORIN_3A-like_TM.
DR   InterPro; IPR024407; Protein_3a_bCoV.
DR   Pfam; PF11289; bCoV_viroporin; 1.
DR   PROSITE; PS51967; COV_VIROPORIN_3A_CD; 1.
DR   PROSITE; PS51966; COV_VIROPORIN_3A_TM; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Apoptosis; Glycoprotein; Host cell membrane; Host cytoplasm;
KW   Host Golgi apparatus; Host membrane; Host-virus interaction;
KW   Inhibition of host innate immune response by virus;
KW   Inhibition of host interferon receptors by virus;
KW   Inhibition of host interferon signaling pathway by virus; Ion channel;
KW   Ion transport; Membrane; Reference proteome; Secreted; Transmembrane;
KW   Transmembrane helix; Transport; Viral immunoevasion; Viral ion channel;
KW   Virion.
FT   CHAIN           1..274
FT                   /note="ORF3a protein"
FT                   /id="PRO_0000106131"
FT   TOPO_DOM        1..34
FT                   /note="Extracellular"
FT                   /evidence="ECO:0000305|PubMed:15194747"
FT   TRANSMEM        35..55
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        56..78
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        79..99
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        100..104
FT                   /note="Extracellular"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        105..125
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        126..274
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000305|PubMed:15194747"
FT   DOMAIN          33..141
FT                   /note="CoV 3a-like viroporin TM"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01311"
FT   DOMAIN          145..237
FT                   /note="CoV 3a-like viroporin CD"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01312"
FT   SITE            133
FT                   /note="Involved in polymerization"
FT   CARBOHYD        27
FT                   /note="O-linked (GalNAc...) serine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        28
FT                   /note="O-linked (GalNAc...) threonine; by host"
FT                   /evidence="ECO:0000305|PubMed:16474139"
FT   CARBOHYD        32
FT                   /note="O-linked (GalNAc...) threonine; by host"
FT                   /evidence="ECO:0000305|PubMed:16474139"
FT   CARBOHYD        34
FT                   /note="O-linked (GalNAc...) threonine; by host"
FT                   /evidence="ECO:0000255"
FT   VARIANT         11
FT                   /note="G -> R (in strain: Isolate Tor2, Isolate BJ02 and
FT                   Isolate BJ03)"
FT   VARIANT         20
FT                   /note="I -> T (in strain: Isolate Shanghai LY)"
FT   VARIANT         29
FT                   /note="V -> A (in strain: Isolate Shanghai QXC1)"
FT   VARIANT         101
FT                   /note="M -> K (in strain: Isolate HKU-39849)"
FT   VARIANT         129
FT                   /note="L -> F (in strain: Isolate TWK)"
FT   VARIANT         136
FT                   /note="K -> Q (in strain: Isolate BJ01)"
FT   VARIANT         171
FT                   /note="E -> A (in strain: Isolate GD01)"
FT   VARIANT         193
FT                   /note="R -> W (in strain: Isolate GD01)"
FT   VARIANT         222
FT                   /note="D -> N (in strain: Isolate Shanghai QXC1)"
FT   MUTAGEN         27
FT                   /note="S->G: Complete loss of O-glycosylation; when
FT                   associated with A-28; A-32 and A-34."
FT                   /evidence="ECO:0000269|PubMed:16474139"
FT   MUTAGEN         28
FT                   /note="T->A: Complete loss of O-glycosylation; when
FT                   associated with A-27; A-32 and A-34."
FT                   /evidence="ECO:0000269|PubMed:16474139"
FT   MUTAGEN         32
FT                   /note="T->A: Complete loss of O-glycosylation; when
FT                   associated with A-27; A-28 and A-34."
FT                   /evidence="ECO:0000269|PubMed:16474139"
FT   MUTAGEN         34
FT                   /note="T->A: Complete loss of O-glycosylation; when
FT                   associated with A-27; A-28 and A-32."
FT                   /evidence="ECO:0000269|PubMed:16474139"
FT   MUTAGEN         81
FT                   /note="C->A: No effect on polymerization."
FT                   /evidence="ECO:0000269|PubMed:16894145"
FT   MUTAGEN         117
FT                   /note="C->A: No effect on polymerization."
FT                   /evidence="ECO:0000269|PubMed:16894145"
FT   MUTAGEN         121
FT                   /note="C->A: No effect on polymerization."
FT                   /evidence="ECO:0000269|PubMed:16894145"
FT   MUTAGEN         127
FT                   /note="C->A: No effect on polymerization."
FT                   /evidence="ECO:0000269|PubMed:16894145"
FT   MUTAGEN         130
FT                   /note="C->A: No effect on polymerization."
FT                   /evidence="ECO:0000269|PubMed:16894145"
FT   MUTAGEN         133
FT                   /note="C->A: Almost complete loss of polymerization
FT                   ability."
FT                   /evidence="ECO:0000269|PubMed:16894145"
FT   MUTAGEN         148
FT                   /note="C->A: No effect on polymerization."
FT                   /evidence="ECO:0000269|PubMed:16894145"
FT   MUTAGEN         157
FT                   /note="C->A: No effect on polymerization."
FT                   /evidence="ECO:0000269|PubMed:16894145"
SQ   SEQUENCE   274 AA;  30903 MW;  E48C7D44A4DE34FE CRC64;
     MDLFMRFFTL GSITAQPVKI DNASPASTVH ATATIPLQAS LPFGWLVIGV AFLAVFQSAT
     KIIALNKRWQ LALYKGFQFI CNLLLLFVTI YSHLLLVAAG MEAQFLYLYA LIYFLQCINA
     CRIIMRCWLC WKCKSKNPLL YDANYFVCWH THNYDYCIPY NSVTDTIVVT EGDGISTPKL
     KEDYQIGGYS EDRHSGVKDY VVVHGYFTEV YYQLESTQIT TDTGIENATF FIFNKLVKDP
     PNVQIHTIDG SSGVANPAMD PIYDEPTTTT SVPL
//