Information on EC 5.4.99.12 - tRNA pseudouridine38-40 synthase

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The expected taxonomic range for this enzyme is: Eukaryota, Bacteria

EC NUMBER
COMMENTARY
5.4.99.12
-
RECOMMENDED NAME
GeneOntology No.
tRNA pseudouridine38-40 synthase
REACTION
REACTION DIAGRAM
COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
tRNA uridine38-40 = tRNA pseudouridine38-40
show the reaction diagram
-
-
-
-
tRNA uridine38-40 = tRNA pseudouridine38-40
show the reaction diagram
the mechanism of pseudouridine synthase I is deduced from its interaction with 5-fluorouracil-tRNA. The covalent complex formed between pseudouridine synthase I and 5-fluorouracil-tRNA involves Michael adduct formation between Asp60 of pseudouridine synthase I and the 6-carbon of 5-fluorouracil39 of tRNA to form a covalent pseudouridine synthase I-5-fluorouracil-tRNA complex
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tRNA uridine38-40 = tRNA pseudouridine38-40
show the reaction diagram
structural, computational, and functional studies provide the basis for a substrate recognition model for the regional selectivity. By binding to the conserved parts of tRNAs (elbow and D stem backbone), TruA recognizes multiple tRNAs independent of sequence variations. Anchored at these two regions, TruA positions the anticodon stem loop near the active site without constraining its flexibility, thereby increasing the effective concentration of each target position, 38, 39, and 40, in the vicinity of the active site. The thermal motions of the anticodon stem loop allow the nucleotides at each of the three sites to be dynamically accessible for modification. TruA utilizes the intrinsic flexibility of the anticodon stem loop for site promiscuity and also to select against intrinsically stable tRNAs
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tRNA uridine38-40 = tRNA pseudouridine38-40
show the reaction diagram
chemical evidence against a covalent cysteine intermediate in the rearrangement mechanism of uridine to pseudouridine
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SYSTEMATIC NAME
IUBMB Comments
tRNA-uridine38-40 uracil mutase
The uridylate residues at positions 38, 39 and 40 of nearly all tRNAs are isomerized to pseudouridine. TruA specifically modifies uridines at positions 38, 39, and/or 40 in the anticodon stem loop of tRNAs with highly divergent sequences and structures [1].
SYNONYMS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
hisT
-
gene name
mPus3p
Q9JI38
-
pseudouridine synthase
-
-
pseudouridine synthase 3
Q9JI38
-
pseudouridine synthase I
-
-
pseudouridine synthase I
P07649
-
pseudouridine synthase I
-
-
PUS3
P31115
gene name
tRNA pseudouridine synthase 3
P31115
-
tRNA pseudouridine synthase I
-
-
tRNA pseudouridine synthase I
P07649
-
TruA
-, P07649
-
CAS REGISTRY NUMBER
COMMENTARY
430429-15-5
-
61506-89-6
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COFACTOR
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
additional information
-
no cofactors required
-
METALS and IONS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
additional information
-
a monovalent cation is required for maximum activity
ACTIVATING COMPOUND
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
additional information
-
a thiol is required for maximum activity
-
KM VALUE [mM]
KM VALUE [mM] Maximum
SUBSTRATE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
0.000086
-
Escherichia coli tRNAPhe uridine39
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wild-type, pH 8.0, 30C
-
0.00011
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Escherichia coli tRNAPhe uridine39
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mutant C55A/C154A/C169A, pH 8.0, 30C
-
0.000086
-
tRNA uridine39
-
pH 8.0, 30, wild-type enzyme
-
0.00011
-
tRNA uridine39
-
pH 8.0, 30C, mutant enzyme C55A/C154A/C169A
-
0.00094
-
tRNA uridine39
-
pH 8.0, 22C
-
0.0018
-
tRNA uridine39
-
pH 8.0, 15C
-
0.0000053
-
tRNAHis guanidine36 uridine38 cytidine39
-
pH 8.0, 30C
-
0.0000804
-
tRNAHis uridine38 cytidine39
-
pH 8.0, 30C
-
0.0000456
-
tRNAHis uridine38 uridine39
-
pH 8.0, 30C
-
0.000669
-
tRNAVal2a cytidine36 uridine38
-
pH 8.0, 30C
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TURNOVER NUMBER [1/s]
TURNOVER NUMBER MAXIMUM[1/s]
SUBSTRATE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
0.18
-
tRNA uridine39
-
pH 8.0, 15C
-
0.73
-
tRNA uridine39
-
pH 8.0, 22C
-
0.0019
-
tRNAHis guanidine36 uridine38 cytidine39
-
pH 8.0, 30C
-
0.0746
-
tRNAHis uridine38 cytidine39
-
pH 8.0, 30C
-
0.144
-
tRNAHis uridine38 uridine39
-
pH 8.0, 30C
-
0.0244
-
tRNAVal2a cytidine36 uridine38
-
pH 8.0, 30C
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kcat/KM VALUE [1/mMs-1]
kcat/KM VALUE [1/mMs-1] Maximum
SUBSTRATE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
160
-
tRNA uridine38
-
pH 8.0, wild-type enzyme
0
100
-
tRNA uridine39
-
pH 8.0, 15C
0
200
-
tRNA uridine39
-
pH 8.0, wild-type enzyme
0
777
-
tRNA uridine39
-
pH 8.0, 22C
0
860
-
tRNA uridine40
-
pH 8.0, wild-type enzyme
0
0.16
-
tRNALeu3
-
pH 8.0, 22C
0
0.2
-
tRNALeu3 carrying uridine at position 39
-
pH 8.0, 22C
0
0.86
-
tRNALeu3 carrying uridine at position 40
-
pH 8.0, 22C
0
Ki VALUE [mM]
Ki VALUE [mM] Maximum
INHIBITOR
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
0.0001
-
fluorouracil-substituted tRNA
-
-
-
pH OPTIMUM
pH MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
8
-
-
assay at
SOURCE TISSUE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
SOURCE
TEMPERATURE STABILITY
TEMPERATURE STABILITY MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
22
-
-
1 h, about 50% loss of activity
STORAGE STABILITY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
-20C or 2C, 50% w/v glycerol, 50% loss of activity after 2 years
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EXPRESSION
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
hisT transcription is positively growth rate regulated in exponentially growing bacteria and is induced during the transition from exponential to stationary growth phase
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