ID   SSRP_SYNR3              Reviewed;         166 AA.
AC   A5GQ67;
DT   15-JAN-2008, integrated into UniProtKB/Swiss-Prot.
DT   12-JUN-2007, sequence version 1.
DT   25-MAY-2022, entry version 80.
DE   RecName: Full=SsrA-binding protein {ECO:0000255|HAMAP-Rule:MF_00023};
DE   AltName: Full=Small protein B {ECO:0000255|HAMAP-Rule:MF_00023};
GN   Name=smpB {ECO:0000255|HAMAP-Rule:MF_00023};
GN   OrderedLocusNames=SynRCC307_0123;
OS   Synechococcus sp. (strain RCC307).
OC   Bacteria; Cyanobacteria; Synechococcales; Synechococcaceae; Synechococcus;
OC   unclassified Synechococcus.
OX   NCBI_TaxID=316278;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=RCC307;
RG   Genoscope;
RL   Submitted (MAY-2006) to the EMBL/GenBank/DDBJ databases.
CC   -!- FUNCTION: Required for rescue of stalled ribosomes mediated by trans-
CC       translation. Binds to transfer-messenger RNA (tmRNA), required for
CC       stable association of tmRNA with ribosomes. tmRNA and SmpB together
CC       mimic tRNA shape, replacing the anticodon stem-loop with SmpB. tmRNA is
CC       encoded by the ssrA gene; the 2 termini fold to resemble tRNA(Ala) and
CC       it encodes a 'tag peptide', a short internal open reading frame. During
CC       trans-translation Ala-aminoacylated tmRNA acts like a tRNA, entering
CC       the A-site of stalled ribosomes, displacing the stalled mRNA. The
CC       ribosome then switches to translate the ORF on the tmRNA; the nascent
CC       peptide is terminated with the 'tag peptide' encoded by the tmRNA and
CC       targeted for degradation. The ribosome is freed to recommence
CC       translation, which seems to be the essential function of trans-
CC       translation. {ECO:0000255|HAMAP-Rule:MF_00023}.
CC   -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000255|HAMAP-Rule:MF_00023}.
CC       Note=The tmRNA-SmpB complex associates with stalled 70S ribosomes.
CC       {ECO:0000255|HAMAP-Rule:MF_00023}.
CC   -!- SIMILARITY: Belongs to the SmpB family. {ECO:0000255|HAMAP-
CC       Rule:MF_00023}.
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DR   EMBL; CT978603; CAK27026.1; -; Genomic_DNA.
DR   RefSeq; WP_011934541.1; NC_009482.1.
DR   AlphaFoldDB; A5GQ67; -.
DR   SMR; A5GQ67; -.
DR   STRING; 316278.SynRCC307_0123; -.
DR   EnsemblBacteria; CAK27026; CAK27026; SynRCC307_0123.
DR   KEGG; syr:SynRCC307_0123; -.
DR   eggNOG; COG0691; Bacteria.
DR   HOGENOM; CLU_108953_0_1_3; -.
DR   OMA; WTNHSAR; -.
DR   OrthoDB; 1720952at2; -.
DR   Proteomes; UP000001115; Chromosome.
DR   GO; GO:0005737; C:cytoplasm; IEA:UniProtKB-SubCell.
DR   GO; GO:0003723; F:RNA binding; IEA:UniProtKB-UniRule.
DR   GO; GO:0070929; P:trans-translation; IEA:UniProtKB-UniRule.
DR   CDD; cd09294; SmpB; 1.
DR   Gene3D; 2.40.280.10; -; 1.
DR   HAMAP; MF_00023; SmpB; 1.
DR   InterPro; IPR023620; SmpB.
DR   InterPro; IPR000037; SsrA-bd_prot.
DR   InterPro; IPR020081; SsrA-bd_prot_CS.
DR   PANTHER; PTHR30308; PTHR30308; 1.
DR   Pfam; PF01668; SmpB; 1.
DR   SUPFAM; SSF74982; SSF74982; 1.
DR   TIGRFAMs; TIGR00086; smpB; 1.
DR   PROSITE; PS01317; SSRP; 1.
PE   3: Inferred from homology;
KW   Cytoplasm; Reference proteome; RNA-binding.
FT   CHAIN           1..166
FT                   /note="SsrA-binding protein"
FT                   /id="PRO_1000002177"
FT   REGION          142..166
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
SQ   SEQUENCE   166 AA;  18978 MW;  E399BF75C2567C0B CRC64;
     MAGKGKGAKA AAKKRLEAQK LLADNRQARH QYEILDTLET GIELLGTEVK AIRAGKANLR
     DGFCLIRQGQ LQLHNVHIAG HEQASRYFNH EPLRVRRLLA HRREIDKLRG QLDTKGLTLI
     PLNIHLKGSW IKLTIGLGKG RKLHDKRQEE RRKQDQKDLR SALKRL