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Literature summary for 6.1.1.1 extracted from

  • Austin, J.; First, E.A.
    Comparison of the catalytic roles played by the KMSKS motif in the human and Bacillus stearothermophilus trosyl-tRNA synthetases (2002), J. Biol. Chem., 277, 28394-28399.
    View publication on PubMed

Cloned(Commentary)

Cloned (Comment) Organism
expression of wild-type and mutant enzymes as His-tagged proteins in Escherichia coli Homo sapiens

Protein Variants

Protein Variants Comment Organism
K231A site-directed mutagenesis, no effect on the catalytic activity of the enzyme Homo sapiens
K233A mutant shows a reduced affinity for ATP Geobacillus stearothermophilus
S224A site-directed mutagenesis, 7.5fold decrease of the forward rate constant Homo sapiens
S225A site-directed mutagenesis, no effect on the catalytic activity of the enzyme Homo sapiens
S226A site-directed mutagenesis, 60fold decrease of the forward rate constant Homo sapiens
T234A decrease of the forward rate constant by 540fold, 3fold increase in affinity of the enzyme for ATP Geobacillus stearothermophilus

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.021
-
L-tyrosine pH 7.5, 25°C, mutant S225A Homo sapiens
0.03
-
L-tyrosine pH 7.5, 25°C, mutant K231A Homo sapiens
0.034
-
L-tyrosine pH 7.5, 25°C, wild-type enzyme Homo sapiens
0.042
-
L-tyrosine pH 7.5, 25°C, mutant S226A Homo sapiens
0.05
-
L-tyrosine pH 7.5, 25°C, mutant S224A Homo sapiens
3
-
ATP pH 7.5, 25°C, mutant S225A and mutant K231A Homo sapiens
4
-
ATP pH 7.5, 25°C, wild-type enzyme and mutant S224A Homo sapiens
4.1
-
ATP pH 7.5, 25°C, mutant S226A Homo sapiens
22
-
K+ pH 7.5, 25°C, mutant S226A Homo sapiens
24
-
K+ pH 7.5, 25°C, mutant S224A Homo sapiens
30
-
K+ pH 7.5, 25°C, mutant S225A Homo sapiens
32
-
K+ pH 7.5, 25°C, wild-type enzyme Homo sapiens

Metals/Ions

Metals/Ions Comment Organism Structure
K+ activates the wild-type enzyme and mutants S225A and K231A, no interaction with the KMSSS motif Homo sapiens
Mg2+ required Homo sapiens
Mg2+ required, MgATP2- Geobacillus stearothermophilus

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
ATP + L-tyrosine + tRNATyr Homo sapiens
-
AMP + L-Tyr-tRNATyr + diphosphate
-
r
ATP + tyrosine + tRNATyr Geobacillus stearothermophilus
-
AMP + Tyr-tRNATyr + diphosphate
-
r

Organism

Organism UniProt Comment Textmining
Geobacillus stearothermophilus
-
-
-
Homo sapiens
-
-
-

Purification (Commentary)

Purification (Comment) Organism
recombinant wild-type and mutant His-tagged enzymes Homo sapiens

Reaction

Reaction Comment Organism Reaction ID
ATP + L-tyrosine + tRNATyr = AMP + diphosphate + L-tyrosyl-tRNATyr S224 and S226 are involved in the catalytic mechanism, the sequence 222KKSSS226, termed KMSSS motif, stabilizes the the transition state for the tyrosine activation reactionby interacting with the diphosphate moiety of ATP Homo sapiens
ATP + L-tyrosine + tRNATyr = AMP + diphosphate + L-tyrosyl-tRNATyr the 230KFGKT234 sequence, termed the KMSKS motif, participates in catalysis of the tyrosine activation reaction, specifically Lys230, Lys233, and Thr234 stabilize the transition state by interacting with the diphosphate moiety of the ATP cofactor Geobacillus stearothermophilus

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
ATP + L-tyrosine + tRNATyr
-
Homo sapiens AMP + L-Tyr-tRNATyr + diphosphate
-
r
ATP + L-tyrosine + tRNATyr 2-step reaction mechanism, 1. activation of the amino acid by MgATP2- to form an enzyme-bound aminoacyl-adenylate intermediate, 2. transfer of the amino acid to the 3'-end of its cognate tRNATyr Homo sapiens AMP + L-Tyr-tRNATyr + diphosphate
-
r
ATP + tyrosine + tRNATyr
-
Geobacillus stearothermophilus AMP + Tyr-tRNATyr + diphosphate
-
r
ATP + tyrosine + tRNATyr 2-step reaction mechanism, 1. activation of the amino acid by MgATP2- to form an enzyme-bound aminoacyl-adenylate intermediate, 2. transfer of the amino acid to the 3'-end of its cognate tRNATyr Geobacillus stearothermophilus AMP + Tyr-tRNATyr + diphosphate
-
r

Synonyms

Synonyms Comment Organism
Tyrosyl-tRNA synthetase
-
Homo sapiens
Tyrosyl-tRNA synthetase
-
Geobacillus stearothermophilus
TyrRS
-
Homo sapiens
TyrRS
-
Geobacillus stearothermophilus

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
25
-
assay at Homo sapiens

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
0.78
-
L-tyrosine pH 7.5, 25°C, mutant S226A Homo sapiens
6
-
L-tyrosine pH 7.5, 25°C, mutant S224A Homo sapiens
6.08
-
L-tyrosine pH 7.5, 25°C, mutant S226A Homo sapiens
30
-
L-tyrosine pH 7.5, 25°C, mutant K231A Homo sapiens
31
-
L-tyrosine pH 7.5, 25°C, mutant S225A Homo sapiens
45
-
L-tyrosine pH 7.5, 25°C, wild-type enzyme Homo sapiens

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
7.5
-
assay at Homo sapiens

Cofactor

Cofactor Comment Organism Structure
ATP
-
Homo sapiens
ATP dependent on, MgATP2- Geobacillus stearothermophilus