ID   SSRP_THEMA              Reviewed;         150 AA.
AC   P56944;
DT   30-MAY-2000, integrated into UniProtKB/Swiss-Prot.
DT   30-MAY-2000, sequence version 1.
DT   03-AUG-2022, entry version 108.
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=TM_0254;
OS   Thermotoga maritima (strain ATCC 43589 / DSM 3109 / JCM 10099 / NBRC 100826
OS   / MSB8).
OC   Bacteria; Thermotogae; Thermotogales; Thermotogaceae; Thermotoga.
OX   NCBI_TaxID=243274;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC 43589 / DSM 3109 / JCM 10099 / NBRC 100826 / MSB8;
RX   PubMed=10360571; DOI=10.1038/20601;
RA   Nelson K.E., Clayton R.A., Gill S.R., Gwinn M.L., Dodson R.J., Haft D.H.,
RA   Hickey E.K., Peterson J.D., Nelson W.C., Ketchum K.A., McDonald L.A.,
RA   Utterback T.R., Malek J.A., Linher K.D., Garrett M.M., Stewart A.M.,
RA   Cotton M.D., Pratt M.S., Phillips C.A., Richardson D.L., Heidelberg J.F.,
RA   Sutton G.G., Fleischmann R.D., Eisen J.A., White O., Salzberg S.L.,
RA   Smith H.O., Venter J.C., Fraser C.M.;
RT   "Evidence for lateral gene transfer between Archaea and Bacteria from
RT   genome sequence of Thermotoga maritima.";
RL   Nature 399:323-329(1999).
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}.
CC   -!- SEQUENCE CAUTION:
CC       Sequence=AE000512; Type=Frameshift; Evidence={ECO:0000305};
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DR   EMBL; AE000512; -; NOT_ANNOTATED_CDS; Genomic_DNA.
DR   RefSeq; WP_011943280.1; NZ_CP011107.1.
DR   PDB; 7LJP; X-ray; 2.10 A; A/B/C=1-150.
DR   PDBsum; 7LJP; -.
DR   AlphaFoldDB; P56944; -.
DR   SMR; P56944; -.
DR   STRING; 243274.THEMA_03455; -.
DR   KEGG; tmw:THMA_0261; -.
DR   PATRIC; fig|243274.19.peg.251; -.
DR   eggNOG; COG0691; Bacteria.
DR   InParanoid; P56944; -.
DR   OMA; WTNHSAR; -.
DR   Proteomes; UP000008183; Chromosome.
DR   GO; GO:0005829; C:cytosol; IBA:GO_Central.
DR   GO; GO:0003723; F:RNA binding; IBA:GO_Central.
DR   GO; GO:0070929; P:trans-translation; IEA:UniProtKB-UniRule.
DR   GO; GO:0070930; P:trans-translation-dependent protein tagging; IBA:GO_Central.
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   1: Evidence at protein level;
KW   3D-structure; Cytoplasm; Reference proteome; RNA-binding.
FT   CHAIN           1..150
FT                   /note="SsrA-binding protein"
FT                   /id="PRO_0000103054"
SQ   SEQUENCE   150 AA;  17594 MW;  06519CDBFB328391 CRC64;
     MVKVVATNKK AYTDYEILET YEAGIVLTGT EVKSLRNGSV NFKDSFCRFK NGELYLLNLH
     IPPYSHGGVY NHDPERPRKL LLHKRELKRL MGKVQEEGVT IVPLKIYFND RGIAKVEIAV
     ARGKKKYDKR EAIKKREMER KIREYMKYSR