HAMAP logo

HAMAP rule MF_00168

Send feedback

General rule information [?]

Accession MF_00168
Dates 1-JUN-2001 (Created)
31-JAN-2024 (Last updated, Version 42)
Name Q_tRNA_Tgt
Scope(s) Bacteria
Template(s) P28720 (TGT_ZYMMO); P0A847 (TGT_ECOLI); [ Recover all ]
Triggered by
case c? <OC:Bacteria>
HAMAP; MF_00168 (Get profile general information and statistics)
end case

Propagated annotation [?]

Identifier, protein and gene names [?]

Identifier TGT
case <OC:Bacteria>
Protein name RecName: Full=Queuine tRNA-ribosyltransferase;
AltName: Full=Guanine insertion enzyme;
AltName: Full=tRNA-guanine transglycosylase;
else case <OC:Archaea>
Protein name RecName: Full=Putative queuine tRNA-ribosyltransferase;
AltName: Full=Guanine insertion enzyme;
AltName: Full=tRNA-guanine transglycosylase;
end case
Gene name Name=tgt;

Comments [?]

FUNCTIONCatalyzes the base-exchange of a guanine (G) residue with the queuine precursor 7-aminomethyl-7-deazaguanine (PreQ1) at position 34 (anticodon wobble position) in tRNAs with GU(N) anticodons (tRNA-Asp, -Asn, -His and -Tyr). Catalysis occurs through a double-displacement mechanism. The nucleophile active site attacks the C1' of nucleotide 34 to detach the guanine base from the RNA, forming a covalent enzyme-RNA intermediate. The proton acceptor active site deprotonates the incoming PreQ1, allowing a nucleophilic attack on the C1' of the ribose to form the product. After dissociation, two additional enzymatic reactions on the tRNA convert PreQ1 to queuine (Q), resulting in the hypermodified nucleoside queuosine (7-(((4,5-cis-dihydroxy-2-cyclopenten-1- yl)amino)methyl)-7-deazaguanosine).
CATALYTIC ACTIVITY Reaction=7-aminomethyl-7-carbaguanine + guanosine(34) in tRNA = 7- aminomethyl-7-carbaguanosine(34) in tRNA + guanine; Xref=Rhea:RHEA:24104, Rhea:RHEA-COMP:10341, Rhea:RHEA-COMP:10342, ChEBI:CHEBI:16235, ChEBI:CHEBI:58703, ChEBI:CHEBI:74269, ChEBI:CHEBI:82833; EC=;
case <FTGroup:1>
COFACTOR Name=Zn(2+); Xref=ChEBI:CHEBI:29105; Note=Binds 1 zinc ion per subunit.;
end case
case <OC:Bacteria>
PATHWAYtRNA modification; tRNA-queuosine biosynthesis.
end case
SUBUNITHomodimer. Within each dimer, one monomer is responsible for RNA recognition and catalysis, while the other monomer binds to the replacement base PreQ1.
SIMILARITYBelongs to the queuine tRNA-ribosyltransferase family.

Keywords [?]

case <OC:Bacteria>
Queuosine biosynthesis
end case
tRNA processing
case <FTGroup:1>
end case

Gene Ontology [?]

GO:0008479; Molecular function:tRNA-guanosine(34) queuine transglycosylase activity
case <OCellular component:Bacteria>
GO:0008616; Biological process:queuosine biosynthetic process
end case
GO:0006400; Biological process:tRNA modification

Cross-references [?]

Pfam PF01702; TGT; 1;
NCBIfam TIGR00430; Q_tRNA_tgt; 1;
NCBIfam TIGR00449; Tgt_general; 1;

Features [?]

From: TGT_ZYMMO (P28720)
Key From To Description Tag Condition FTGroup
BINDING 102 106 /ligand="substrate" D-S-G-G-[FY]
REGION 261 267 /note="RNA binding" G-[VIG]-G-x(4)
REGION 285 289 /note="RNA binding; important for wobble base 34 recognition" [TA]-[RK]-x(2)-R
ACT_SITE 102 102 /note="Proton acceptor" D
ACT_SITE 280 280 /note="Nucleophile" D
BINDING 318 318 /ligand="Zn(2+)"
C 1
BINDING 320 320 /ligand="Zn(2+)"
C 1
BINDING 323 323 /ligand="Zn(2+)"
C 1
BINDING 349 349 /ligand="Zn(2+)"
H 1
BINDING 156 156 /ligand="substrate" D
BINDING 203 203 /ligand="substrate" Q
BINDING 230 230 /ligand="substrate" G

Additional information [?]

Size range 361-403 amino acids
Related rules None
Fusion Nter: None Cter: None

View rule in raw text format (no links)