ID   SSRP_LACDA              Reviewed;         153 AA.
AC   Q1G8P4;
DT   29-APR-2008, integrated into UniProtKB/Swiss-Prot.
DT   27-JUN-2006, 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=Ldb1832;
OS   Lactobacillus delbrueckii subsp. bulgaricus (strain ATCC 11842 / DSM 20081
OS   / BCRC 10696 / JCM 1002 / NBRC 13953 / NCIMB 11778 / NCTC 12712 / WDCM
OS   00102 / Lb 14).
OC   Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae;
OC   Lactobacillus.
OX   NCBI_TaxID=390333;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC 11842 / DSM 20081 / BCRC 10696 / JCM 1002 / NBRC 13953 / NCIMB
RC   11778 / NCTC 12712 / WDCM 00102 / Lb 14;
RX   PubMed=16754859; DOI=10.1073/pnas.0603024103;
RA   van de Guchte M., Penaud S., Grimaldi C., Barbe V., Bryson K., Nicolas P.,
RA   Robert C., Oztas S., Mangenot S., Couloux A., Loux V., Dervyn R., Bossy R.,
RA   Bolotin A., Batto J.-M., Walunas T., Gibrat J.-F., Bessieres P.,
RA   Weissenbach J., Ehrlich S.D., Maguin E.;
RT   "The complete genome sequence of Lactobacillus bulgaricus reveals extensive
RT   and ongoing reductive evolution.";
RL   Proc. Natl. Acad. Sci. U.S.A. 103:9274-9279(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; CR954253; CAI98601.1; -; Genomic_DNA.
DR   RefSeq; WP_003611142.1; NZ_JQAV01000021.1.
DR   AlphaFoldDB; Q1G8P4; -.
DR   SMR; Q1G8P4; -.
DR   STRING; 390333.Ldb1832; -.
DR   EnsemblBacteria; CAI98601; CAI98601; Ldb1832.
DR   KEGG; ldb:Ldb1832; -.
DR   PATRIC; fig|390333.13.peg.1075; -.
DR   eggNOG; COG0691; Bacteria.
DR   HOGENOM; CLU_108953_0_0_9; -.
DR   OMA; WTNHSAR; -.
DR   BioCyc; LDEL390333:LDB_RS07945-MON; -.
DR   Proteomes; UP000001259; 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..153
FT                   /note="SsrA-binding protein"
FT                   /id="PRO_0000331055"
SQ   SEQUENCE   153 AA;  17916 MW;  DA15C58658D6DDF1 CRC64;
     MKQKAKDENV LAQNRQARHD YFIKDTYEAG IALTGTEIKS VRARHVTLRD GYVQIINGSA
     FLENVHIDEY KEGNRYNHDP LRSRRLLLHK KEIAKLADVK AQKGMTIVPL KVYLKHGFAK
     VLIGVAQGKK EYDKRETIKK RDQDRELRRK YRI