ID   2B_TAV                  Reviewed;          95 AA.
AC   Q8UYT3;
DT   04-DEC-2007, integrated into UniProtKB/Swiss-Prot.
DT   01-MAR-2002, sequence version 1.
DT   02-JUN-2021, entry version 61.
DE   RecName: Full=Suppressor of silencing 2b;
DE   AltName: Full=Protein 2b;
GN   ORFNames=ORF2b;
OS   Tomato aspermy virus (TAV).
OC   Viruses; Riboviria; Orthornavirae; Kitrinoviricota; Alsuviricetes;
OC   Martellivirales; Bromoviridae; Cucumovirus.
OX   NCBI_TaxID=12315;
OH   NCBI_TaxID=4627; Canna.
OH   NCBI_TaxID=41568; Chrysanthemum morifolium (Florist's daisy) (Dendranthema grandiflorum).
OH   NCBI_TaxID=4688; Lilium.
OH   NCBI_TaxID=4081; Solanum lycopersicum (Tomato) (Lycopersicon esculentum).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RX   PubMed=2016592; DOI=10.1099/0022-1317-72-4-779;
RA   Moriones E., Roossinck M.J., Garcia-Arenal F.;
RT   "Nucleotide sequence of tomato aspermy virus RNA 2.";
RL   J. Gen. Virol. 72:779-783(1991).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RC   STRAIN=KC-TAV;
RX   PubMed=11911475;
RA   Choi S.K., Choi J.K., Ryu K.H., Park W.M.;
RT   "Generation of infectious cDNA clones of a Korean strain of tomato aspermy
RT   virus.";
RL   Mol. Cells 13:52-60(2002).
RN   [3]
RP   FUNCTION.
RX   PubMed=8291242; DOI=10.1006/viro.1994.1071;
RA   Ding S.W., Anderson B.J., Haase H.R., Symons R.H.;
RT   "New overlapping gene encoded by the cucumber mosaic virus genome.";
RL   Virology 198:593-601(1994).
RN   [4]
RP   FUNCTION.
RX   PubMed=9010309; DOI=10.1099/0022-1317-78-1-237;
RA   Shi B.J., Ding S.W., Symons R.H.;
RT   "In vivo expression of an overlapping gene encoded by the cucumoviruses.";
RL   J. Gen. Virol. 78:237-241(1997).
RN   [5]
RP   FUNCTION.
RX   PubMed=10329615; DOI=10.1093/emboj/18.10.2683;
RA   Li H.-W., Lucy A.P., Guo H.-S., Li W.-X., Ji L.-H., Wong S.-M., Ding S.-W.;
RT   "Strong host resistance targeted against a viral suppressor of the plant
RT   gene silencing defence mechanism.";
RL   EMBO J. 18:2683-2691(1999).
RN   [6]
RP   X-RAY CRYSTALLOGRAPHY (2.82 ANGSTROMS) OF 1-69 IN COMPLEX WITH A SMALL
RP   INTERFERING RNA DUPLEX, AND SUBUNIT.
RX   PubMed=18600235; DOI=10.1038/embor.2008.118;
RA   Chen H.Y., Yang J., Lin C., Yuan Y.A.;
RT   "Structural basis for RNA-silencing suppression by Tomato aspermy virus
RT   protein 2b.";
RL   EMBO Rep. 9:754-760(2008).
CC   -!- FUNCTION: Acts as suppressor of RNA-mediated gene silencing, also known
CC       as post-transcriptional gene silencing (PTGS), a mechanism of plant
CC       viral defense that limits the accumulation of viral RNAs. Forms a
CC       homodimer to measure siRNA duplex in a length-preference mode. Binds to
CC       both siRNA duplexes (19bp) and long siRNA duplexes (30bp).
CC       {ECO:0000269|PubMed:10329615, ECO:0000269|PubMed:8291242,
CC       ECO:0000269|PubMed:9010309}.
CC   -!- SUBUNIT: Homodimer. Homotetramer (dimer of dimers).
CC       {ECO:0000269|PubMed:18600235}.
CC   -!- SUBCELLULAR LOCATION: Host nucleus {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the cucumovirus/ilarvirus protein 2b family.
CC       {ECO:0000305}.
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DR   EMBL; D10663; -; NOT_ANNOTATED_CDS; Genomic_RNA.
DR   EMBL; AJ320274; CAC86465.1; -; Genomic_RNA.
DR   RefSeq; NP_620826.1; NC_003838.1.
DR   PDB; 2ZI0; X-ray; 2.82 A; A/B=1-69.
DR   PDB; 3CZ3; X-ray; 3.23 A; A/B/C/D=1-69.
DR   PDBsum; 2ZI0; -.
DR   PDBsum; 3CZ3; -.
DR   SMR; Q8UYT3; -.
DR   GeneID; 962654; -.
DR   KEGG; vg:962654; -.
DR   EvolutionaryTrace; Q8UYT3; -.
DR   Proteomes; UP000007399; Genome.
DR   GO; GO:0042025; C:host cell nucleus; IEA:UniProtKB-SubCell.
DR   GO; GO:0003723; F:RNA binding; IEA:UniProtKB-KW.
DR   InterPro; IPR004946; Cucumo_2B.
DR   Pfam; PF03263; Cucumo_2B; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Coiled coil; Host nucleus; Reference proteome; RNA-binding;
KW   Suppressor of RNA silencing.
FT   CHAIN           1..95
FT                   /note="Suppressor of silencing 2b"
FT                   /id="PRO_0000312150"
FT   REGION          8..18
FT                   /note="Homotetramerization"
FT   REGION          16..49
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COILED          8..40
FT                   /evidence="ECO:0000255"
FT   MOTIF           26..30
FT                   /note="Nuclear localization signal"
FT                   /evidence="ECO:0000250"
FT   COMPBIAS        20..35
FT                   /note="Basic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   HELIX           8..35
FT                   /evidence="ECO:0007829|PDB:2ZI0"
FT   HELIX           41..61
FT                   /evidence="ECO:0007829|PDB:2ZI0"
SQ   SEQUENCE   95 AA;  11165 MW;  D4F262B2DB394C47 CRC64;
     MASIEIPLHE IIRKLERMNQ KKQAQRKRHK LNRKERGHKS PSEQRRSELW HARQVELSAI
     NSDNSSDEGT TLCRFDTFGS KSDAICDRSD WCLDQ