ID   SSRP_LACAC              Reviewed;         151 AA.
AC   Q5FLT4;
DT   07-JUN-2005, integrated into UniProtKB/Swiss-Prot.
DT   01-MAR-2005, sequence version 1.
DT   03-AUG-2022, entry version 87.
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}; OrderedLocusNames=LBA0450;
OS   Lactobacillus acidophilus (strain ATCC 700396 / NCK56 / N2 / NCFM).
OC   Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae;
OC   Lactobacillus.
OX   NCBI_TaxID=272621;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC 700396 / NCK56 / N2 / NCFM;
RX   PubMed=15671160; DOI=10.1073/pnas.0409188102;
RA   Altermann E., Russell W.M., Azcarate-Peril M.A., Barrangou R., Buck B.L.,
RA   McAuliffe O., Souther N., Dobson A., Duong T., Callanan M., Lick S.,
RA   Hamrick A., Cano R., Klaenhammer T.R.;
RT   "Complete genome sequence of the probiotic lactic acid bacterium
RT   Lactobacillus acidophilus NCFM.";
RL   Proc. Natl. Acad. Sci. U.S.A. 102:3906-3912(2005).
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; CP000033; AAV42340.1; -; Genomic_DNA.
DR   RefSeq; WP_003550138.1; NC_006814.3.
DR   RefSeq; YP_193371.1; NC_006814.3.
DR   AlphaFoldDB; Q5FLT4; -.
DR   SMR; Q5FLT4; -.
DR   STRING; 272621.LBA0450; -.
DR   PRIDE; Q5FLT4; -.
DR   EnsemblBacteria; AAV42340; AAV42340; LBA0450.
DR   GeneID; 56942086; -.
DR   KEGG; lac:LBA0450; -.
DR   PATRIC; fig|272621.13.peg.434; -.
DR   eggNOG; COG0691; Bacteria.
DR   HOGENOM; CLU_108953_0_0_9; -.
DR   OMA; WTNHSAR; -.
DR   BioCyc; LACI272621:G1G49-475-MON; -.
DR   Proteomes; UP000006381; 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..151
FT                   /note="SsrA-binding protein"
FT                   /id="PRO_0000102963"
SQ   SEQUENCE   151 AA;  17694 MW;  E26176B5D08C064A CRC64;
     MKEKEENLIA QNKKARHDYF IKETLEAGIA LTGTEIKSVR ARRINLRDGY VQIINGSAYL
     ENVHISEYKQ GNRYNHDPLR SRRLLLHKKE INRLAKVQAE RGIAIIPLKV YLKHGFAKVL
     IGVGQGKKEY DKRQTIKERD QKREIRRKYG I