ID   CAPSD_BPF2              Reviewed;         129 AA.
AC   P03611;
DT   21-JUL-1986, integrated into UniProtKB/Swiss-Prot.
DT   21-JUL-1986, sequence version 1.
DT   03-AUG-2022, entry version 73.
DE   RecName: Full=Capsid protein;
DE            Short=CP;
DE   AltName: Full=Coat protein;
OS   Enterobacteria phage f2 (Bacteriophage f2).
OC   Viruses; Riboviria; Orthornavirae; Lenarviricota; Leviviricetes;
OC   Levivirales; Leviviridae; Levivirus.
OX   NCBI_TaxID=12016;
OH   NCBI_TaxID=562; Escherichia coli.
RN   [1]
RP   PROTEIN SEQUENCE.
RA   Weber K., Konigsberg W.;
RT   "Amino acid sequence of the f-2 coat protein.";
RL   J. Biol. Chem. 242:3563-3578(1967).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA] OF 81-99.
RX   PubMed=5572609; DOI=10.1016/0005-2787(71)90731-3;
RA   Nichols J.L., Robertson H.D.;
RT   "Sequences of RNA fragments from the bacteriophage f2 coat protein cistron
RT   which differ from their R17 counterparts.";
RL   Biochim. Biophys. Acta 228:676-681(1971).
CC   -!- FUNCTION: Capsid protein self-assembles to form an icosahedral capsid
CC       with a T=3 symmetry, about 26 nm in diameter, and consisting of 89
CC       capsid proteins dimers (178 capsid proteins). Involved in viral genome
CC       encapsidation through the interaction between a capsid protein dimer
CC       and the multiple packaging signals present in the RNA genome. The
CC       capsid contains also 1 copy of the A2 maturation protein.
CC       {ECO:0000250|UniProtKB:P03612}.
CC   -!- FUNCTION: Acts as a translational repressor of viral replicase
CC       synthesis late in infection. This latter function is the result of
CC       capsid protein interaction with an RNA hairpin which contains the
CC       replicase ribosome-binding site. {ECO:0000250|UniProtKB:P03612}.
CC   -!- SUBUNIT: Homodimer. The capsid proteins form dimers that assemble by
CC       group of 5. Twelve such pentamers are linked together with free dimers.
CC       The homodimers binds to the viral RNA via an operator hairpin, but also
CC       to many other RNA sequences in the viral genome; this interaction
CC       probably shifts the virus from the replicative to the assembly phase
CC       and ensures specific encapsidation of the viral genome.
CC       {ECO:0000250|UniProtKB:P03612}.
CC   -!- SUBCELLULAR LOCATION: Virion {ECO:0000250|UniProtKB:P03612}. Note=The
CC       shell is composed of 178 copies of the capsid protein and 1 copy of the
CC       maturation protein. {ECO:0000250|UniProtKB:P03612}.
CC   -!- SIMILARITY: Belongs to the Levivirus capsid protein family.
CC       {ECO:0000305}.
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DR   EMBL; M24832; AAA32227.1; -; Genomic_RNA.
DR   PIR; A04222; VCBPF2.
DR   SMR; P03611; -.
DR   GO; GO:0039617; C:T=3 icosahedral viral capsid; IEA:UniProtKB-KW.
DR   GO; GO:0003723; F:RNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0005198; F:structural molecule activity; IEA:InterPro.
DR   GO; GO:0006417; P:regulation of translation; IEA:UniProtKB-KW.
DR   Gene3D; 3.30.380.10; -; 1.
DR   InterPro; IPR002703; Levivir_coat.
DR   InterPro; IPR015954; Phage_RNA-type_capsid.
DR   Pfam; PF01819; Levi_coat; 1.
DR   SUPFAM; SSF55405; SSF55405; 1.
PE   1: Evidence at protein level;
KW   Capsid protein; Direct protein sequencing; RNA-binding;
KW   T=3 icosahedral capsid protein; Translation regulation; Virion.
FT   CHAIN           1..129
FT                   /note="Capsid protein"
FT                   /id="PRO_0000164839"
FT   REGION          31..104
FT                   /note="Viral RNA-binding"
FT                   /evidence="ECO:0000250|UniProtKB:P03612"
SQ   SEQUENCE   129 AA;  13710 MW;  6F43970F09A9EBB7 CRC64;
     ASNFTQFVLV NDGGTGNVTV APSNFANGVA EWISSNSRSQ AYKVTCSVRQ SSAQNRKYTI
     KVEVPKVATQ TVGGVELPVA AWRSYLNLEL TIPIFATNSD CELIVKAMQG LLKDGNPIPS
     AIAANSGIY