ID   B2_NODAM                Reviewed;         137 AA.
AC   Q9IMM3;
DT   30-NOV-2010, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-2000, sequence version 1.
DT   27-MAR-2024, entry version 45.
DE   RecName: Full=Protein B2;
GN   Name=B2;
OS   Nodamura virus (strain Mag115) (NoV).
OC   Viruses; Riboviria; Orthornavirae; Kitrinoviricota; Magsaviricetes;
OC   Nodamuvirales; Nodaviridae; Alphanodavirus; Nodamura virus.
OX   NCBI_TaxID=914672;
OH   NCBI_TaxID=7158; Aedes.
OH   NCBI_TaxID=7088; Lepidoptera (butterflies and moths).
OH   NCBI_TaxID=9823; Sus scrofa (Pig).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA], AND ALTERNATIVE INITIATION.
RX   PubMed=12573589; DOI=10.1006/viro.2002.1769;
RA   Johnson K.L., Price B.D., Ball L.A.;
RT   "Recovery of infectivity from cDNA clones of nodamura virus and
RT   identification of small nonstructural proteins.";
RL   Virology 305:436-451(2003).
RN   [2]
RP   X-RAY CRYSTALLOGRAPHY (2.5 ANGSTROMS) OF 1-78, FUNCTION, AND RNA-BINDING.
RX   PubMed=19249868; DOI=10.1021/bi900126s;
RA   Korber S., Shaik Syed Ali P., Chen J.C.;
RT   "Structure of the RNA-binding domain of nodamura virus protein B2, a
RT   suppressor of RNA interference.";
RL   Biochemistry 48:2307-2309(2009).
CC   -!- FUNCTION: Binds double-strand RNA (dsRNA) with high affinity.
CC       Suppresses the host RNA silencing-based antiviral response.
CC       {ECO:0000250|UniProtKB:P68831}.
CC   -!- SUBUNIT: Homodimer. Interacts with RNA-directed RNA polymerase.
CC       {ECO:0000250|UniProtKB:P68831}.
CC   -!- SUBCELLULAR LOCATION: Host mitochondrion
CC       {ECO:0000250|UniProtKB:P68831}.
CC   -!- ALTERNATIVE PRODUCTS:
CC       Event=Alternative initiation; Named isoforms=2;
CC       Name=1; Synonyms=B2/137;
CC         IsoId=Q9IMM3-1; Sequence=Displayed;
CC       Name=2; Synonyms=B2/134;
CC         IsoId=Q9IMM3-2; Sequence=VSP_040284;
CC   -!- DOMAIN: The dsRNA-binding region is required for suppression of RNA
CC       silencing. The N-terminus is involved in homodimerization. The alpha2
CC       helices of the dimer bind parallel to the stem of the dsRNA helix.
CC       {ECO:0000250|UniProtKB:P68831}.
CC   -!- MISCELLANEOUS: Encoded on a subgenomic RNA (RNA3) synthesized during
CC       replication and which is co-terminal with RNA1.
CC   -!- MISCELLANEOUS: [Isoform 2]: Produced by alternative initiation at Met-4
CC       of isoform 1. {ECO:0000305}.
CC   -!- SIMILARITY: Belongs to the nodaviridae B2 protein family.
CC       {ECO:0000305}.
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DR   EMBL; AF174533; AAF97861.1; -; Genomic_RNA.
DR   RefSeq; NP_077731.1; NC_002690.1.
DR   PDB; 3G80; X-ray; 2.50 A; A/B=1-78.
DR   PDBsum; 3G80; -.
DR   SMR; Q9IMM3; -.
DR   KEGG; vg:962118; -.
DR   EvolutionaryTrace; Q9IMM3; -.
DR   Proteomes; UP000166289; Genome.
DR   GO; GO:0033650; C:host cell mitochondrion; IEA:UniProtKB-SubCell.
DR   GO; GO:0003723; F:RNA binding; IEA:UniProtKB-KW.
DR   Gene3D; 1.10.287.1060; ESAT-6-like; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Alternative initiation; Host mitochondrion;
KW   Host-virus interaction; Inhibition of host innate immune response by virus;
KW   Reference proteome; RNA-binding; Suppressor of RNA silencing;
KW   Viral immunoevasion.
FT   CHAIN           1..137
FT                   /note="Protein B2"
FT                   /id="PRO_0000402409"
FT   REGION          1..79
FT                   /note="RNA-binding"
FT   VAR_SEQ         1..3
FT                   /note="Missing (in isoform 2)"
FT                   /evidence="ECO:0000305"
FT                   /id="VSP_040284"
FT   HELIX           7..12
FT                   /evidence="ECO:0007829|PDB:3G80"
FT   HELIX           14..30
FT                   /evidence="ECO:0007829|PDB:3G80"
FT   HELIX           37..65
FT                   /evidence="ECO:0007829|PDB:3G80"
FT   HELIX           68..74
FT                   /evidence="ECO:0007829|PDB:3G80"
SQ   SEQUENCE   137 AA;  15033 MW;  440131FB758CC062 CRC64;
     MTNMSCAYEL IKSLPAKLEQ LAQETQATIQ TLMIADPNVN KDLRAFCEFL TVQHQRAYRA
     TNSLLIKPRV AAALRGEELD LGEADVAARV RQLKQQLAEL EMEIKPGHQQ VAQVSGRRKA
     AAAAPVAQLG RVGVVNE
//