ID   SSRP_LACLS              Reviewed;         155 AA.
AC   Q02XF3;
DT   15-JAN-2008, integrated into UniProtKB/Swiss-Prot.
DT   14-NOV-2006, sequence version 1.
DT   25-MAY-2022, entry version 85.
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=LACR_1883;
OS   Lactococcus lactis subsp. cremoris (strain SK11).
OC   Bacteria; Firmicutes; Bacilli; Lactobacillales; Streptococcaceae;
OC   Lactococcus; Lactococcus cremoris subsp. cremoris.
OX   NCBI_TaxID=272622;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=SK11;
RX   PubMed=17030793; DOI=10.1073/pnas.0607117103;
RA   Makarova K.S., Slesarev A., Wolf Y.I., Sorokin A., Mirkin B., Koonin E.V.,
RA   Pavlov A., Pavlova N., Karamychev V., Polouchine N., Shakhova V.,
RA   Grigoriev I., Lou Y., Rohksar D., Lucas S., Huang K., Goodstein D.M.,
RA   Hawkins T., Plengvidhya V., Welker D., Hughes J., Goh Y., Benson A.,
RA   Baldwin K., Lee J.-H., Diaz-Muniz I., Dosti B., Smeianov V., Wechter W.,
RA   Barabote R., Lorca G., Altermann E., Barrangou R., Ganesan B., Xie Y.,
RA   Rawsthorne H., Tamir D., Parker C., Breidt F., Broadbent J.R., Hutkins R.,
RA   O'Sullivan D., Steele J., Unlu G., Saier M.H. Jr., Klaenhammer T.,
RA   Richardson P., Kozyavkin S., Weimer B.C., Mills D.A.;
RT   "Comparative genomics of the lactic acid bacteria.";
RL   Proc. Natl. Acad. Sci. U.S.A. 103:15611-15616(2006).
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; CP000425; ABJ73369.1; -; Genomic_DNA.
DR   RefSeq; WP_011676717.1; NC_008527.1.
DR   AlphaFoldDB; Q02XF3; -.
DR   SMR; Q02XF3; -.
DR   EnsemblBacteria; ABJ73369; ABJ73369; LACR_1883.
DR   GeneID; 61109980; -.
DR   KEGG; llc:LACR_1883; -.
DR   HOGENOM; CLU_108953_0_1_9; -.
DR   OMA; WTNHSAR; -.
DR   Proteomes; UP000000240; 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; RNA-binding.
FT   CHAIN           1..155
FT                   /note="SsrA-binding protein"
FT                   /id="PRO_1000002074"
SQ   SEQUENCE   155 AA;  17934 MW;  316D6BB262E96AF8 CRC64;
     MVKNTEDKPL AQNKKARHDY EIYETFEAGI VLTGTEIKSV RQAKIQLKDG FARVRNGEVW
     LSNVHIAPFE QGNIFNVEEL RTRKLLLNKK EIAKIDKELS GTGITFIPLK VYLKNGFAKV
     LMGLARGKKD YDKRESLKRK EQNRDIARQL KAYNR