TGT_HELPS
ID TGT_HELPS Reviewed; 371 AA.
AC B2USB2;
DT 24-MAR-2009, integrated into UniProtKB/Swiss-Prot.
DT 01-JUL-2008, sequence version 1.
DT 03-AUG-2022, entry version 71.
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=HPSH_01460;
OS Helicobacter pylori (strain Shi470).
OC Bacteria; Proteobacteria; Epsilonproteobacteria; Campylobacterales;
OC Helicobacteraceae; Helicobacter.
OX NCBI_TaxID=512562;
RN [1]
RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC STRAIN=Shi470;
RA Kersulyte D., Kalia A., Gilman R.H., Berg D.E.;
RT "Genome sequence of Helicobacter pylori from the remote Amazon: traces of
RT Asian ancestry of the first Americans.";
RL Submitted (MAY-2008) to the EMBL/GenBank/DDBJ databases.
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; CP001072; ACD47744.1; -; Genomic_DNA.
DR RefSeq; WP_000347410.1; NC_010698.2.
DR AlphaFoldDB; B2USB2; -.
DR SMR; B2USB2; -.
DR KEGG; hps:HPSH_01460; -.
DR HOGENOM; CLU_022060_0_1_7; -.
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..371
FT /note="Queuine tRNA-ribosyltransferase"
FT /id="PRO_1000097548"
FT REGION 246..252
FT /note="RNA binding"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00168"
FT REGION 270..274
FT /note="RNA binding; important for wobble base 34
FT recognition"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00168"
FT ACT_SITE 90
FT /note="Proton acceptor"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00168"
FT ACT_SITE 265
FT /note="Nucleophile"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00168"
FT BINDING 90..94
FT /ligand="substrate"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00168"
FT BINDING 144
FT /ligand="substrate"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00168"
FT BINDING 189
FT /ligand="substrate"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00168"
FT BINDING 215
FT /ligand="substrate"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00168"
FT BINDING 303
FT /ligand="Zn(2+)"
FT /ligand_id="ChEBI:CHEBI:29105"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00168"
FT BINDING 305
FT /ligand="Zn(2+)"
FT /ligand_id="ChEBI:CHEBI:29105"
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 334
FT /ligand="Zn(2+)"
FT /ligand_id="ChEBI:CHEBI:29105"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00168"
SQ SEQUENCE 371 AA; 41391 MW; 1DFCDD3BD036B661 CRC64;
MDFQLQATDN NARAGLLNLA HSQVATPVFM PVGTQGCIKS LDATDMQGIL GAKLILANTY
HLYLRPGEKV VEELGGLHRF AQFHGSFLTD SGGFQAFSLS DNVKLQEDGI VFKSHIDGSK
HLFTPAKVLD IQYSLNSDIM MVLDDLVGLP APLKRLEESI KRSAKWANLS LEYHKQKNRP
NNNLFAIIQG GTHLKMRSLS VGLTHEGFDG YAIGGLAVGE SADEMLETIA HTAPLLPKDK
PRYLMGVGTP ENILDAIGLG VDMFDCVMPT RNARNATLFT HSGKISIKNA PYKLDDTPIE
ENCACYTCKR YSKAYLHHLF RAKELTYARL ASLHNLHFYL ELVKNARNAI LEKRFLSFKK
EFLKKYHSRS H
