AC   MF_03218;
DC   Protein; auto
c?   <OC:Eukaryota>
TR   HAMAP; MF_00168; -; 1; level=0
XX
Names: Q_tRNA_Tgt_euk
XX
ID   TGT
DE   RecName: Full=Queuine tRNA-ribosyltransferase catalytic subunit 1;
DE            EC=2.4.2.64;
DE   AltName: Full=Guanine insertion enzyme;
DE   AltName: Full=tRNA-guanine transglycosylase;
case <OC:Vertebrata>
GN   Name=QTRT1;
else case <OC:Caenorhabditis>
GN   Name=tgt-1;
end case
XX
CC   -!- FUNCTION: Catalytic subunit of the queuine tRNA-ribosyltransferase
CC       (TGT) that catalyzes the base-exchange of a guanine (G) residue with
CC       queuine (Q) at position 34 (anticodon wobble position) in tRNAs with
CC       GU(N) anticodons (tRNA-Asp, -Asn, -His and -Tyr), resulting in the
CC       hypermodified nucleoside queuosine (7-(((4,5-cis-dihydroxy-2-
CC       cyclopenten-1-yl)amino)methyl)-7-deazaguanosine). Catalysis occurs
CC       through a double-displacement mechanism. The nucleophile active site
CC       attacks the C1' of nucleotide 34 to detach the guanine base from the
CC       RNA, forming a covalent enzyme-RNA intermediate. The proton acceptor
CC       active site deprotonates the incoming queuine, allowing a nucleophilic
CC       attack on the C1' of the ribose to form the product.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=guanosine(34) in tRNA + queuine = guanine + queuosine(34) in
CC         tRNA; Xref=Rhea:RHEA:16633, Rhea:RHEA-COMP:10341, Rhea:RHEA-
CC         COMP:18571, ChEBI:CHEBI:16235, ChEBI:CHEBI:17433, ChEBI:CHEBI:74269,
CC         ChEBI:CHEBI:194431; EC=2.4.2.64;
case <FTGroup:1>
CC   -!- COFACTOR:
CC       Name=Zn(2+); Xref=ChEBI:CHEBI:29105;
end case
case <OC:Vertebrata>
CC   -!- SUBUNIT: Heterodimer of a catalytic subunit @gn(QTRT1) and an accessory
CC       subunit @gn(QTRT2).
CC   -!- SUBCELLULAR LOCATION: Cytoplasm. Mitochondrion outer membrane;
CC       Peripheral membrane protein; Cytoplasmic side. Note=Weakly associates
CC       with mitochondria, possibly via @gn(QTRT2).
else
CC   -!- SUBUNIT: Heterodimer of a catalytic subunit and an accessory subunit.
CC   -!- SUBCELLULAR LOCATION: Cytoplasm.
end case
CC   -!- SIMILARITY: Belongs to the queuine tRNA-ribosyltransferase family.
XX
DR   Pfam; PF01702; TGT; 1; trigger=no
DR   NCBIfam; TIGR00430; Q_tRNA_tgt; 1; trigger=no
DR   NCBIfam; TIGR00449; tgt_general; 1; trigger=no
XX
KW   Cytoplasm
case <OC:Vertebrata>
KW   Mitochondrion
KW   Mitochondrion outer membrane
KW   Membrane
end case
KW   Glycosyltransferase
KW   Transferase
KW   tRNA processing
case <FTGroup:1>
KW   Metal-binding
KW   Zinc
end case
XX
GO   GO:0005737; C:cytoplasm
case <OC:Vertebrata>
GO   GO:0005741; C:mitochondrial outer membrane
end case
GO   GO:0008479; F:tRNA-guanosine(34) queuine transglycosylase activity
GO   GO:0101030; P:tRNA-guanine transglycosylation
XX
FT   From: TGT_ZYMMO (P28720)
FT   BINDING         102..106
FT                   /ligand="substrate"
FT   Condition: D-S-G-G-[FY]
FT   REGION          261..267
FT                   /note="RNA binding"
FT   Condition: G-[VIG]-G-x(4)
FT   REGION          285..289
FT                   /note="RNA binding; important for wobble base 34
FT                   recognition"
FT   Condition: [TA]-[RK]-x(2)-R
FT   ACT_SITE        102
FT                   /note="Proton acceptor"
FT   Condition: D
FT   ACT_SITE        280
FT                   /note="Nucleophile"
FT   Condition: D
FT   BINDING         318
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT   Group: 1; Condition: C
FT   BINDING         320
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT   Group: 1; Condition: C
FT   BINDING         323
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT   Group: 1; Condition: C
FT   BINDING         349
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT   Group: 1; Condition: H
FT   BINDING         156
FT                   /ligand="substrate"
FT   Condition: D
FT   BINDING         203
FT                   /ligand="substrate"
FT   Condition: Q
FT   BINDING         230
FT                   /ligand="substrate"
FT   Condition: G
XX
Size: 396-427;
Related: None;
Template: Q9BXR0; P28720; P0A847; Q9JMA2;
Scope:
 Eukaryota
Fusion:
 Nter: None
 Cter: None
Duplicate: None
Plasmid: None
Comments: None
XX
# Revision 1.13 2023/07/27
//