RT78_ECOLX
ID RT78_ECOLX Reviewed; 311 AA.
AC Q46666;
DT 03-AUG-2022, integrated into UniProtKB/Swiss-Prot.
DT 03-AUG-2022, sequence version 2.
DT 03-AUG-2022, entry version 53.
DE RecName: Full=Retron Ec78 reverse transcriptase {ECO:0000303|PubMed:9281493};
DE Short=RT {ECO:0000303|PubMed:9281493};
DE EC=2.7.7.49 {ECO:0000255|PROSITE-ProRule:PRU00405, ECO:0000305|PubMed:9281493};
GN Name=ret {ECO:0000303|PubMed:9281493}; ORFNames=Ga0100609_101822;
OS Escherichia coli.
OC Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales;
OC Enterobacteriaceae; Escherichia.
OX NCBI_TaxID=562;
RN [1] {ECO:0000312|EMBL:AAA03713.1}
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA], AND PROBABLE FUNCTION.
RC STRAIN=Clinical strain 110;
RX PubMed=9281493; DOI=10.1006/plas.1997.1298;
RA Lima T.M., Lim D.;
RT "A novel retron that produces RNA-less msDNA in Escherichia coli using
RT reverse transcriptase.";
RL Plasmid 38:25-33(1997).
RN [2] {ECO:0000312|EMBL:JHRW01000018}
RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC STRAIN=102598;
RA Hazen T.H., Donnenberg M., Nataro J., Kaper J., Rasko D.;
RT "Emergence of novel diverse phylogenomic lineages of EPEC.";
RL Submitted (AUG-2015) to the EMBL/GenBank/DDBJ databases.
RN [3]
RP FUNCTION.
RC STRAIN=Clinical strain 110;
RX PubMed=7885227; DOI=10.1111/j.1365-2958.1994.tb02178.x;
RA Maas W.K., Wang C., Lima T., Zubay G., Lim D.;
RT "Multicopy single-stranded DNAs with mismatched base pairs are mutagenic in
RT Escherichia coli.";
RL Mol. Microbiol. 14:437-441(1994).
RN [4]
RP MSDNA MATURATION BY EXOVII.
RX PubMed=26626352; DOI=10.1007/s12275-015-5304-0;
RA Jung H., Liang J., Jung Y., Lim D.;
RT "Characterization of cell death in Escherichia coli mediated by XseA, a
RT large subunit of exonuclease VII.";
RL J. Microbiol. 53:820-828(2015).
RN [5]
RP FUNCTION IN ANTIVIRAL DEFENSE, AND INDENTIFICATION AS A RETRON.
RC STRAIN=102598;
RX PubMed=33157039; DOI=10.1016/j.cell.2020.09.065;
RA Millman A., Bernheim A., Stokar-Avihail A., Fedorenko T., Voichek M.,
RA Leavitt A., Oppenheimer-Shaanan Y., Sorek R.;
RT "Bacterial Retrons Function In Anti-Phage Defense.";
RL Cell 183:1551-1561(2020).
CC -!- FUNCTION: Reverse transcriptase (RT) component of antiviral defense
CC system retron Ec78, composed of a non-coding RNA (ncRNA), this reverse
CC transcriptase (RT), a probable ATPase and a putative HNH endonuclease.
CC Expression of retron Ec78 confers protection against bacteriophage T5.
CC At multiplicity of infection (MOI) of 0.02 cultures slow growth when
CC infected with T5 but do not collapse, at MOI 2 cultures enter growth
CC stasis (PubMed:33157039). Responsible for synthesis of msDNA-Ec78 (a
CC linear ssDNA with a 5'-terminal phosphate residue). Unlike most known
CC msDNAs the mature product does not have an RNA component. The retron
CC transcript serves as primer and template for the reaction, and codes
CC for the RT. Not mutagenic when cloned in E.coli (PubMed:9281493). It is
CC thought to be synthesized as a branched RNA with a 2',5'-phosphodiester
CC linkage to ssDNA; the linkage is cleaved endonucleolytically by ExoVII
CC (xseA-xseB) leaving the observed mature 5'-ssDNA terminus (Probable)
CC (PubMed:26626352). Overexpression of the ncRNA and RT, which leads to
CC increased levels of msDNA, is not mutagenic in vivo. As the stem in the
CC msDNA does not have a mismatch it probably does not bind or sequester
CC MutS and/or MutL (PubMed:7885227). {ECO:0000269|PubMed:26626352,
CC ECO:0000269|PubMed:33157039, ECO:0000269|PubMed:7885227,
CC ECO:0000269|PubMed:9281493, ECO:0000305|PubMed:9281493}.
CC -!- CATALYTIC ACTIVITY:
CC Reaction=a 2'-deoxyribonucleoside 5'-triphosphate + DNA(n) =
CC diphosphate + DNA(n+1); Xref=Rhea:RHEA:22508, Rhea:RHEA-COMP:17339,
CC Rhea:RHEA-COMP:17340, ChEBI:CHEBI:33019, ChEBI:CHEBI:61560,
CC ChEBI:CHEBI:173112; EC=2.7.7.49; Evidence={ECO:0000255|PROSITE-
CC ProRule:PRU00405, ECO:0000305|PubMed:9281493};
CC -!- SIMILARITY: Belongs to the bacterial reverse transcriptase family.
CC {ECO:0000305}.
CC -!- SEQUENCE CAUTION:
CC Sequence=AAA03713.1; Type=Frameshift; Evidence={ECO:0000305};
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DR EMBL; U02551; AAA03713.1; ALT_FRAME; Genomic_DNA.
DR EMBL; JHRW01000018; -; NOT_ANNOTATED_CDS; Genomic_DNA.
DR SMR; Q46666; -.
DR GO; GO:0003723; F:RNA binding; IEA:InterPro.
DR GO; GO:0003964; F:RNA-directed DNA polymerase activity; IEA:UniProtKB-KW.
DR CDD; cd03487; RT_Bac_retron_II; 1.
DR InterPro; IPR043502; DNA/RNA_pol_sf.
DR InterPro; IPR000123; Reverse_transcriptase_msDNA.
DR InterPro; IPR000477; RT_dom.
DR Pfam; PF00078; RVT_1; 1.
DR PRINTS; PR00866; RNADNAPOLMS.
DR SUPFAM; SSF56672; SSF56672; 1.
DR PROSITE; PS50878; RT_POL; 1.
PE 1: Evidence at protein level;
KW Antiviral defense; Magnesium; Metal-binding; Nucleotidyltransferase;
KW RNA-binding; RNA-directed DNA polymerase; Transferase.
FT CHAIN 1..311
FT /note="Retron Ec78 reverse transcriptase"
FT /id="PRO_0000456019"
FT DOMAIN 15..241
FT /note="Reverse transcriptase"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00405"
FT BINDING 96
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /ligand_note="catalytic"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00405"
FT BINDING 187
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /ligand_note="catalytic"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00405"
FT BINDING 188
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /ligand_note="catalytic"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00405"
FT CONFLICT 273..283
FT /note="DKAYLTGLLAF -> KLSDRLLAL (in Ref. 1; AAA03713)"
FT /evidence="ECO:0000305"
SQ SEQUENCE 311 AA; 35503 MW; 75B6B38F00AA1B9C CRC64;
MSVIRRLAAV LRQSDSGISA FLVTAPRKYK VYKIPKRTTG FRVIAQPAKG LKDIQRAFVQ
LYNFPVHDAS MAYMKGKGIR DNAAAHAGNQ YLLKADLEDF FNSITPAIFW RCIEMSSALT
PQFEPQDKFF IEKILFWQPI KHRKTKLILS VGAPSSPVIS NFCMYEFDNR IHAACNKLEI
TYTRYADDLT FSCNIPNVLK AVPSTIEALL KDLFGSELRL NHSKTVFSSK AHNRHVTGVT
INNEETLSLG RDRKRFIKHL INQYKYGLLD NEDKAYLTGL LAFASHIEPG FITRMNEKYS
LELMGRLRGQ R
