ExPASy Proteomics Server

Accession	MF_00168
Dates	1-JUN-2001 (Created) 25-NOV-2009 (Last updated, Version 27)

Data class

Protein

Predictors

HAMAP; MF_00168; [distribution of match scores in UniProtKB];[seed alignment for MF_00168]

Names

Q_tRNA_Tgt

Identifier

TGT

Protein name

RecName: Full=Queuine tRNA-ribosyltransferase; EC=2.4.2.29; AltName: Full=tRNA-guanine transglycosylase; AltName: Full=Guanine insertion enzyme;

Gene name

tgt

FUNCTION: Exchanges the guanine residue with 7-aminomethyl-7-deazaguanine in tRNAs with GU(N) anticodons (tRNA-Asp, -Asn, -His and -Tyr). After this exchange, a cyclopentendiol moiety is attached to the 7-aminomethyl group of 7-deazaguanine, resulting in the hypermodified nucleoside queuosine (Q) (7-(((4,5-cis-dihydroxy-2-cyclopenten-1-yl)amino)methyl)-7-deazaguanosine) (By similarity).

CATALYTIC ACTIVITY: [tRNA]-guanine + queuine = [tRNA]-queuine + guanine.

CATALYTIC ACTIVITY: [tRNA]-guanine + 7-aminomethyl-7-carbaguanine = [tRNA]-7-aminomethyl-7-carbaguanine + guanine.

COFACTOR: Binds 1 zinc ion per subunit (By similarity).

PATHWAY: tRNA modification; tRNA-queuosine biosynthesis.

SIMILARITY: Belongs to the queuine tRNA-ribosyltransferase family.

Pfam	PF01702; TGT; 1;
TIGRFAMs	TIGR00430; Q_tRNA_tgt; 1; TIGR00449; tgt_general; 1;

Queuosine biosynthesis, Transferase, Glycosyltransferase, tRNA processing, Metal-binding, Zinc.

GO:0008479; Molecular function: queuine tRNA-ribosyltransferase activity.
GO:0008616; Biological process: queuosine biosynthetic process.
GO:0008033; Biological process: tRNA processing.

From: TGT_ECOLI (P0A847)
Key		From		To		Description		Condition		FTGroup
ACT_SITE		89		89		Nucleophile (By similarity)		D
METAL		302		302		Zinc (By similarity)		C
METAL		304		304		Zinc (By similarity)		C
METAL		307		307		Zinc (By similarity)		C
METAL		333		333		Zinc (By similarity)		H
BINDING		90		90		Substrate (By similarity)		S

Size range:	361-403 amino acids
Related UniRules:	MF_00603
Template:	P28720 (TGT_ZYMMO); P0A847 (TGT_ECOLI): [Recover all]
Scope:	Bacteria Archaea
Fusion:	Nter: None; Cter: None
Duplicate:	None
Plasmid encoded:	None