ID   P21_BYVU                Reviewed;         177 AA.
AC   Q08545;
DT   04-DEC-2007, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1996, sequence version 1.
DT   02-JUN-2021, entry version 71.
DE   RecName: Full=RNA silencing suppressor;
DE   AltName: Full=21 kDa protein;
DE   AltName: Full=p21;
GN   ORFNames=ORF8;
OS   Beet yellows virus (isolate Ukraine) (BYV) (Sugar beet yellows virus).
OC   Viruses; Riboviria; Orthornavirae; Kitrinoviricota; Alsuviricetes;
OC   Martellivirales; Closteroviridae; Closterovirus.
OX   NCBI_TaxID=478555;
OH   NCBI_TaxID=161934; Beta vulgaris (Sugar beet).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RX   PubMed=1990061; DOI=10.1099/0022-1317-72-1-15;
RA   Agranovsky A.A., Boyko V.P., Karasev A.V., Lunina N.A., Koonin E.V.,
RA   Dolja V.V.;
RT   "Nucleotide sequence of the 3'-terminal half of beet yellows closterovirus
RT   RNA genome: unique arrangement of eight virus genes.";
RL   J. Gen. Virol. 72:15-23(1991).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RX   PubMed=8259666; DOI=10.1006/viro.1994.1034;
RA   Agranovsky A.A., Koonin E.V., Boyko V.P., Maiss E., Froetschl R.,
RA   Lunina N.A., Atabekov J.G.;
RT   "Beet yellows closterovirus: complete genome structure and identification
RT   of a leader papain-like thiol protease.";
RL   Virology 198:311-324(1994).
RN   [3]
RP   FUNCTION, AND SUBCELLULAR LOCATION.
RX   PubMed=12642093; DOI=10.1016/s0042-6822(02)00051-x;
RA   Reed J.C., Kasschau K.D., Prokhnevsky A.I., Gopinath K., Pogue G.P.,
RA   Carrington J.C., Dolja V.V.;
RT   "Suppressor of RNA silencing encoded by Beet yellows virus.";
RL   Virology 306:203-209(2003).
RN   [4]
RP   X-RAY CRYSTALLOGRAPHY (3.3 ANGSTROMS).
RX   PubMed=16154094; DOI=10.1016/j.str.2005.06.017;
RA   Ye K., Patel D.J.;
RT   "RNA silencing suppressor p21 of Beet yellows virus forms an RNA binding
RT   octameric ring structure.";
RL   Structure 13:1375-1384(2005).
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. Binds to
CC       ssRNAs and dsRNAs in vitro. Also functions as replication enhancer.
CC       {ECO:0000269|PubMed:12642093}.
CC   -!- SUBUNIT: Homooctamer. The eight monomers assemble into a closed ring
CC       that binds RNA.
CC   -!- INTERACTION:
CC       Q08545; Q08545: ORF8; NbExp=2; IntAct=EBI-15556683, EBI-15556683;
CC   -!- SUBCELLULAR LOCATION: Host cytoplasm {ECO:0000269|PubMed:12642093}.
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DR   EMBL; X53462; CAA37556.1; -; Genomic_RNA.
DR   EMBL; X73476; CAA51870.1; -; Genomic_RNA.
DR   PIR; S28717; S28717.
DR   RefSeq; NP_041877.1; NC_001598.1.
DR   PDB; 2CWO; X-ray; 3.30 A; A/B/C/D=1-177.
DR   PDBsum; 2CWO; -.
DR   SMR; Q08545; -.
DR   GeneID; 1724788; -.
DR   KEGG; vg:1724788; -.
DR   EvolutionaryTrace; Q08545; -.
DR   Proteomes; UP000000359; Genome.
DR   GO; GO:0030430; C:host cell cytoplasm; IEA:UniProtKB-SubCell.
DR   GO; GO:0042802; F:identical protein binding; IPI:IntAct.
DR   GO; GO:0003723; F:RNA binding; IEA:UniProtKB-KW.
DR   InterPro; IPR021742; RSS_P20_N.
DR   InterPro; IPR021575; Suppressor_P21_C.
DR   Pfam; PF11757; RSS_P20; 1.
DR   Pfam; PF11479; Suppressor_P21; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Host cytoplasm; Reference proteome; RNA-binding;
KW   Suppressor of RNA silencing.
FT   CHAIN           1..177
FT                   /note="RNA silencing suppressor"
FT                   /id="PRO_0000312570"
FT   HELIX           10..24
FT                   /evidence="ECO:0007829|PDB:2CWO"
FT   HELIX           33..61
FT                   /evidence="ECO:0007829|PDB:2CWO"
FT   HELIX           78..89
FT                   /evidence="ECO:0007829|PDB:2CWO"
FT   TURN            90..92
FT                   /evidence="ECO:0007829|PDB:2CWO"
FT   HELIX           102..117
FT                   /evidence="ECO:0007829|PDB:2CWO"
FT   HELIX           121..126
FT                   /evidence="ECO:0007829|PDB:2CWO"
FT   HELIX           129..144
FT                   /evidence="ECO:0007829|PDB:2CWO"
FT   HELIX           150..152
FT                   /evidence="ECO:0007829|PDB:2CWO"
FT   HELIX           156..160
FT                   /evidence="ECO:0007829|PDB:2CWO"
FT   HELIX           165..171
FT                   /evidence="ECO:0007829|PDB:2CWO"
SQ   SEQUENCE   177 AA;  20558 MW;  DFD0D072DF993A76 CRC64;
     MKFFLKDGET SRALSRSESL LRRVKELGTN SQQSEISECV DEFNELASFN HLLVTVEHRE
     WMEQHPNQSS KLRVPSRIGE MLKEIRAFLK VRVVTPMHKE TASDTLNAFL EEYCRITGLA
     REDALREKMR KVKSVVLFHH SELLKFEVTE NMFSYTELLK LNLSLRVISS QILGMAI