TGT_STRTD
ID TGT_STRTD Reviewed; 380 AA.
AC Q03IQ5;
DT 15-JAN-2008, integrated into UniProtKB/Swiss-Prot.
DT 14-NOV-2006, sequence version 1.
DT 03-AUG-2022, entry version 87.
DE RecName: Full=Queuine tRNA-ribosyltransferase {ECO:0000255|HAMAP-Rule:MF_00168};
DE EC=2.4.2.29 {ECO:0000255|HAMAP-Rule:MF_00168};
DE AltName: Full=Guanine insertion enzyme {ECO:0000255|HAMAP-Rule:MF_00168};
DE AltName: Full=tRNA-guanine transglycosylase {ECO:0000255|HAMAP-Rule:MF_00168};
GN Name=tgt {ECO:0000255|HAMAP-Rule:MF_00168}; OrderedLocusNames=STER_1785;
OS Streptococcus thermophilus (strain ATCC BAA-491 / LMD-9).
OC Bacteria; Firmicutes; Bacilli; Lactobacillales; Streptococcaceae;
OC Streptococcus.
OX NCBI_TaxID=322159;
RN [1]
RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC STRAIN=ATCC BAA-491 / LMD-9;
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: Catalyzes the base-exchange of a guanine (G) residue with the
CC queuine precursor 7-aminomethyl-7-deazaguanine (PreQ1) at position 34
CC (anticodon wobble position) in tRNAs with GU(N) anticodons (tRNA-Asp,
CC -Asn, -His and -Tyr). Catalysis occurs through a double-displacement
CC mechanism. The nucleophile active site attacks the C1' of nucleotide 34
CC to detach the guanine base from the RNA, forming a covalent enzyme-RNA
CC intermediate. The proton acceptor active site deprotonates the incoming
CC PreQ1, allowing a nucleophilic attack on the C1' of the ribose to form
CC the product. After dissociation, two additional enzymatic reactions on
CC the tRNA convert PreQ1 to queuine (Q), resulting in the hypermodified
CC nucleoside queuosine (7-(((4,5-cis-dihydroxy-2-cyclopenten-1-
CC yl)amino)methyl)-7-deazaguanosine). {ECO:0000255|HAMAP-Rule:MF_00168}.
CC -!- CATALYTIC ACTIVITY:
CC Reaction=7-aminomethyl-7-carbaguanine + guanosine(34) in tRNA = 7-
CC aminomethyl-7-carbaguanosine(34) in tRNA + guanine;
CC Xref=Rhea:RHEA:24104, Rhea:RHEA-COMP:10341, Rhea:RHEA-COMP:10342,
CC ChEBI:CHEBI:16235, ChEBI:CHEBI:58703, ChEBI:CHEBI:74269,
CC ChEBI:CHEBI:82833; EC=2.4.2.29; Evidence={ECO:0000255|HAMAP-
CC Rule:MF_00168};
CC -!- COFACTOR:
CC Name=Zn(2+); Xref=ChEBI:CHEBI:29105;
CC Evidence={ECO:0000255|HAMAP-Rule:MF_00168};
CC Note=Binds 1 zinc ion per subunit. {ECO:0000255|HAMAP-Rule:MF_00168};
CC -!- PATHWAY: tRNA modification; tRNA-queuosine biosynthesis.
CC {ECO:0000255|HAMAP-Rule:MF_00168}.
CC -!- SUBUNIT: Homodimer. Within each dimer, one monomer is responsible for
CC RNA recognition and catalysis, while the other monomer binds to the
CC replacement base PreQ1. {ECO:0000255|HAMAP-Rule:MF_00168}.
CC -!- SIMILARITY: Belongs to the queuine tRNA-ribosyltransferase family.
CC {ECO:0000255|HAMAP-Rule:MF_00168}.
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DR EMBL; CP000419; ABJ66917.1; -; Genomic_DNA.
DR RefSeq; WP_011681659.1; NC_008532.1.
DR AlphaFoldDB; Q03IQ5; -.
DR SMR; Q03IQ5; -.
DR KEGG; ste:STER_1785; -.
DR HOGENOM; CLU_022060_0_1_9; -.
DR OMA; GIDLFDC; -.
DR UniPathway; UPA00392; -.
DR GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR GO; GO:0008479; F:queuine tRNA-ribosyltransferase activity; IEA:UniProtKB-UniRule.
DR GO; GO:0008616; P:queuosine biosynthetic process; IEA:UniProtKB-UniRule.
DR GO; GO:0101030; P:tRNA-guanine transglycosylation; IEA:InterPro.
DR Gene3D; 3.20.20.105; -; 1.
DR HAMAP; MF_00168; Q_tRNA_Tgt; 1.
DR InterPro; IPR004803; TGT.
DR InterPro; IPR036511; TGT-like_sf.
DR InterPro; IPR002616; tRNA_ribo_trans-like.
DR Pfam; PF01702; TGT; 1.
DR SUPFAM; SSF51713; SSF51713; 1.
DR TIGRFAMs; TIGR00430; Q_tRNA_tgt; 1.
DR TIGRFAMs; TIGR00449; tgt_general; 1.
PE 3: Inferred from homology;
KW Glycosyltransferase; Metal-binding; Queuosine biosynthesis; Transferase;
KW tRNA processing; Zinc.
FT CHAIN 1..380
FT /note="Queuine tRNA-ribosyltransferase"
FT /id="PRO_1000016877"
FT REGION 251..257
FT /note="RNA binding"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00168"
FT REGION 275..279
FT /note="RNA binding; important for wobble base 34
FT recognition"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00168"
FT ACT_SITE 96
FT /note="Proton acceptor"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00168"
FT ACT_SITE 270
FT /note="Nucleophile"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00168"
FT BINDING 96..100
FT /ligand="substrate"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00168"
FT BINDING 150
FT /ligand="substrate"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00168"
FT BINDING 193
FT /ligand="substrate"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00168"
FT BINDING 220
FT /ligand="substrate"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00168"
FT BINDING 308
FT /ligand="Zn(2+)"
FT /ligand_id="ChEBI:CHEBI:29105"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00168"
FT BINDING 310
FT /ligand="Zn(2+)"
FT /ligand_id="ChEBI:CHEBI:29105"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00168"
FT BINDING 313
FT /ligand="Zn(2+)"
FT /ligand_id="ChEBI:CHEBI:29105"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00168"
FT BINDING 339
FT /ligand="Zn(2+)"
FT /ligand_id="ChEBI:CHEBI:29105"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00168"
SQ SEQUENCE 380 AA; 42992 MW; 01463BDA08FB60BD CRC64;
MIDFPIKYRL IKKEKYTGAR LGEIITPHGT FPTPMFMPVG TQATVKTQSP EELKQMGSGI
ILANTYHLWL RPGDELIAKA GGLHKFMNWD QAILTDSGGF QVYSLAEKRD ISEEGVTFKN
HLNGSKMFLS PEKAISVQNN LGSDIMMSFD ECPQFYQPYD YVKKSIERTS RWAERGLKAH
RRPHDQGLFG IVQGAGFEDL RRQSSHDLVS MDFPGYSIGG LAVGETHEEM NAVLDFTVPL
LPENKPRYLM GVGAPDSLID GVIRGVDMYD CVLPTRIARN GTCMTSNGRL VVKNAAYAED
FSPIDPECDC YTCKNYTRAY VRHLLKADET FGIRLTSYHN LYFLVNLMAK VRQAIVDDNL
LEFRQDFIEK YGYNASNRNF
