Information on EC 2.8.1.4 - tRNA uracil 4-sulfurtransferase

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

EC NUMBER
COMMENTARY hide
2.8.1.4
-
RECOMMENDED NAME
GeneOntology No.
tRNA uracil 4-sulfurtransferase
REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
ATP + [ThiI sulfur-carrier protein]-S-sulfanyl-L-cysteine + uracil in tRNA + 2 reduced ferredoxin [iron-sulfur] cluster = AMP + diphosphate + 4-thiouracil in tRNA + [ThiI sulfur-carrier protein]-L-cysteine + 2 oxidized ferredoxin [iron-sulfur] cluster
show the reaction diagram
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
sulfur atom transfer
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-
-
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PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
Thiamine metabolism
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-
Metabolic pathways
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-
SYSTEMATIC NAME
IUBMB Comments
[ThiI sulfur-carrier protein]-S-sulfanyl-L-cysteine:uracil in tRNA sulfurtransferase
The enzyme, found in bacteria and archaea, is activated by EC 2.8.1.7, cysteine desulfurase, which transfers a sulfur atom to an internal L-cysteine residue, forming a cysteine persulfide. The activated enzyme then transfers the sulfur to a uridine in a tRNA chain in a reaction that requires ATP. The enzyme from the bacterium Escherichia coli forms 4-thiouridine only at position 8 of tRNA. The enzyme also participates in the biosynthesis of the thiazole moiety of thiamine, but different domains are involved in the two processes.
CAS REGISTRY NUMBER
COMMENTARY hide
9055-57-6
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ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
W168
-
-
Manually annotated by BRENDA team
W168
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-
Manually annotated by BRENDA team
Ctu1; gene F29C4.6
TrEMBL
Manually annotated by BRENDA team
Escherichia coli B / ATCC 11303
B
-
-
Manually annotated by BRENDA team
HfrC
-
-
Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
malfunction
deletion mutant shows no groth defects compared to wild-type, indicating that MMP1354 is not an essential enzyme; deletion of ThiI abolishes the biosynthesis of 4-thiouridine but not of thiamine; MMP1354 complements an Escherichia coli Thi mutant
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
3-mercaptopyruvate + activated tRNA
? + S-tRNA
show the reaction diagram
L-cysteine + 'activated' tRNA
L-serine + tRNA containing a thionucleotide
show the reaction diagram
L-cysteine + Bacillus subtilis 'activated' tRNA
L-serine + tRNA containing a thionucleotide
show the reaction diagram
L-cysteine + Bos taurus 'activated' tRNA
L-serine + tRNA containing a thionucleotide
show the reaction diagram
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calf liver tRNA better substrate than rat liver tRNA
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-
r
L-cysteine + denatured DNA
L-serine + ?
show the reaction diagram
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DNA prepared from various sources appears to function as a good sulfur acceptor
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?
L-cysteine + E. coli 'activated' tRNA
L-serine + tRNA containing a thionucleotide
show the reaction diagram
L-cysteine + poly A-2poly U
L-serine + S-tRNA
show the reaction diagram
L-cysteine + poly A-poly U
L-serine + S-tRNA
show the reaction diagram
L-cysteine + poly G,U
L-serine + S-tRNA
show the reaction diagram
-
G:U = 2
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-
?
L-cysteine + rabbit liver 'activated' tRNA
L-serine + tRNA containing a thionucleotide
show the reaction diagram
-
-
-
-
r
L-cysteine + Rattus norvegicus brain 'activated' tRNA
L-serine + tRNA containing a thionucleotide
show the reaction diagram
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better substrate than liver tRNA
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r
L-cysteine + Rattus norvegicus liver 'activated' tRNA
L-serine + tRNA containing a thionucleotide
show the reaction diagram
L-cysteine + Saccharomyces cerevisiae 'activated' tRNA
L-serine + tRNA containing a thionucleotide
show the reaction diagram
sulfide + tRNA-uridine
tRNA-4-thiouridine
show the reaction diagram
the enzyme is invoved in biosynthesis of 4-thiouridine in tRNA. 4-Thiouridine, is a modified nucleotide of tRNA that is conserved from bacteria to archaea, where it functions as a sensor for near-UV irradiation
-
-
?
sulfide + [tRNACys]-uridine
[tRNACys]-4-thiouridine
show the reaction diagram
proposed mechanism: first, a sulfur donor (equivalent of S2-) attacks the Cys265Cys268 disulfide linkage to generate a persulfide on either Cys265 or Cys268, leaving the other Cys as a free thiol. Then, a thiolate derived from deprotonation of the free thiol attacks the bridging sulfur of the persulfide to liberate the terminal sulfur. After donation of the sulfur (in the -2 oxidation state) to form 4-thiouridine, the disulfide (with both sulfurs in the -1 oxidation state) is consequently regenerated. No exogenous electron donor or acceptor is required for the catalytic cycle
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?
additional information
?
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NATURAL SUBSTRATES
NATURAL PRODUCTS
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
L-cysteine + 'activated' tRNA
L-serine + tRNA containing a thionucleotide
show the reaction diagram
sulfide + tRNA-uridine
tRNA-4-thiouridine
show the reaction diagram
Q6LXJ6
the enzyme is invoved in biosynthesis of 4-thiouridine in tRNA. 4-Thiouridine, is a modified nucleotide of tRNA that is conserved from bacteria to archaea, where it functions as a sensor for near-UV irradiation
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-
?
additional information
?
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COFACTOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
pyridoxal 5'-phosphate
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-
additional information
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METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
additional information
INHIBITORS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
2-mercaptoethanol
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-
3-Mercaptopyruvate
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competitive inhibitor, supresses the transfer of sulfur to tRNA
Cd2+
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inhibits the synthesis of s4U
Co2+
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inhibits the synthesis of s4U
cysteine
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inhibits reaction with 3-mercaptopyruvate
Fe2+
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inhibits the synthesis of s4U
Ni2+
-
inhibits the synthesis of s4U
Zn2+
-
inhibits the synthesis of s4U
additional information
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dialyzable heat-stable inhibitor with a MW lower 5000 present in Morris hepatoma tumors
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ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
2-mercaptoethanol
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requires a thiol for optimal sulfur transfer
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.0069
3-Mercaptopyruvate
-
pH 7.8, 37C
0.0012 - 1
L-cysteine
1
Sulfide
pH 7.3, 37C
0.0027
tRNA
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pH 7.5, 37C, sulfur deficient tRNA
Ki VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.005
3-Mercaptopyruvate
-
pH 7.8, 37C
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
0.00000372
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0.0000658
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pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
8 - 8.4
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pH RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
7 - 9
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about 75% of activity maximum at pH 7.0, about 55% of activity maximum at pH 9.0
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
TEMPERATURE RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
10 - 37
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at 10C rate of sulfur transfer being 1/3 that at 37C
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
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Morris hepatoma tumors 9618A2, 7777, 5123TC, 7800, 5123B, 7787
Manually annotated by BRENDA team
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highest activity
Manually annotated by BRENDA team
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY hide
GeneOntology No.
LITERATURE
SOURCE
PDB
SCOP
CATH
ORGANISM
UNIPROT
Thermotoga maritima (strain ATCC 43589 / MSB8 / DSM 3109 / JCM 10099)
Thermotoga maritima (strain ATCC 43589 / MSB8 / DSM 3109 / JCM 10099)
Thermotoga maritima (strain ATCC 43589 / MSB8 / DSM 3109 / JCM 10099)
Crystallization/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
in complex with tRNAGlu
pH STABILITY
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
5
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inactivated
643812
STORAGE STABILITY
ORGANISM
UNIPROT
LITERATURE
-20C, freezing causes a 50% loss of sulfurtransferase activity
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-20C, partly purified pooled protein fractions can be stored indefinitely for periods up to several months
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-60C, instable on storage, overnight storage results in 50% lost of activity
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-75C, ammonium sulfate fractionated preparation retains its activity for several months
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0-4C, 50% glycerol, storage of the complex for 1 week results in a loss of 30-60% of the 3 different activities
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0C, only slight loss of enzymatic activity on overnight storage
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4C, addition of toluene, can be stored indefinitely for periods up to several months
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4C, instable, cannot be dialyzed without loss of activity
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Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
partially
sulfurtransferase system with 2 enzymes
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Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
ENGINEERING
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
C265A
cells expressing the C265A variant show 88% decrease in their 4-thiouridine level. The mutant enzyme contains no detectable amount of persulfide
C268A
cells expressing the C265A variant contain no 4-thiouridine. The mutant enzyme contains no detectable amount of persulfide
C348A
cells expressing the C348A variant show 33% decreases in their 4-thiouridine levels. The mutant enzyme contains no detectable amount of persulfide
C78A
cells expressing the C78A variant show 8% decrease in their 4-thiouridine levels. The C78A variant has similar amounts of persulfide as the wild-type protein
additional information
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