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Literature summary for 2.3.3.14 extracted from

  • Okada, T.; Tomita, T.; Wulandari, A.P.; Kuzuyama, T.; Nishiyama, M.
    Mechanism of substrate recognition and insight into feedback inhibition of homocitrate synthase from Thermus thermophilus (2010), J. Biol. Chem., 285, 4195-4205.
    View publication on PubMedView publication on EuropePMC

Cloned(Commentary)

Cloned (Comment) Organism
three expression systems are designed, TtHCS without tag, with a C-terminal His6 tag and with a N-terminal His8 tag, the vectors pBluescript II SK+ and pET26b+ are used for expression in Escherichia coli cells Thermus thermophilus

Crystallization (Commentary)

Crystallization (Comment) Organism
the crystal structures of homocitrate synthase complexed with 2-oxoglutarate, (R)-2-hydroxybutane-1,2,4-tricarboxylate, or lysine are determined Thermus thermophilus

Protein Variants

Protein Variants Comment Organism
H72L replacement of His72 by leucine makes HCS resistant to lysine inhibition, demonstrating the regulatory role of this conserved residue Thermus thermophilus

Inhibitors

Inhibitors Comment Organism Structure
lysine regulated via feedback inhibition by the endproduct Thermus thermophilus

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.0054
-
2-oxoglutarate wild-type enzyme, N-terminal His8 tag Thermus thermophilus
0.033
-
acetyl-CoA wild-type enzyme, N-terminal His8 tag Thermus thermophilus
0.037
-
acetyl-CoA H72L mutant, N-terminal His8 tag Thermus thermophilus
0.174
-
2-oxoglutarate H72L mutant, N-terminal His8 tag Thermus thermophilus

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
acetyl-CoA + H2O + 2-oxoglutarate Thermus thermophilus
-
(R)-2-hydroxybutane-1,2,4-tricarboxylate + CoA
-
?

Organism

Organism UniProt Comment Textmining
Thermus thermophilus
-
-
-

Purification (Commentary)

Purification (Comment) Organism
a Ni2+-nitrilotriacetic acid column, a gel filtration column, a HiLoad 26/60 phenyl-Sepharose column and a Resource Q anion exchange column are used Thermus thermophilus

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
-
-
no activity without additive Thermus thermophilus
0.0003
-
additive CuCl2 Thermus thermophilus
0.0008
-
additive FeSO4 Thermus thermophilus
0.0013
-
additive ZnSO4 Thermus thermophilus
0.0036
-
additive NiCl2 Thermus thermophilus
0.0075
-
additive CaCl2 Thermus thermophilus
0.0333
-
additive CoCl2 Thermus thermophilus
0.0392
-
additive MnCl2 Thermus thermophilus
0.0415
-
additive MgSO4 Thermus thermophilus

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
acetyl-CoA + H2O + 2-oxoglutarate
-
Thermus thermophilus (R)-2-hydroxybutane-1,2,4-tricarboxylate + CoA
-
?

Synonyms

Synonyms Comment Organism
HCS
-
Thermus thermophilus
homocitrate synthase
-
Thermus thermophilus
TtHCS
-
Thermus thermophilus

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
50
-
activity assay Thermus thermophilus

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
0.182
-
2-oxoglutarate wild-type enzyme, N-terminal His8 tag Thermus thermophilus
0.248
-
2-oxoglutarate H72L mutant, N-terminal His8 tag Thermus thermophilus
0.517
-
acetyl-CoA H72L mutant, N-terminal His8 tag Thermus thermophilus
0.683
-
acetyl-CoA wild-type enzyme, N-terminal His8 tag Thermus thermophilus

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
7.5
-
activity assay Thermus thermophilus

Cofactor

Cofactor Comment Organism Structure
acetyl-CoA
-
Thermus thermophilus

Ki Value [mM]

Ki Value [mM] Ki Value maximum [mM] Inhibitor Comment Organism Structure
0.0707
-
lysine wild-type enzyme, N-terminal His8 tag Thermus thermophilus
2
-
lysine H72L mutant, N-terminal His8 tag, larger than 2 Thermus thermophilus

General Information

General Information Comment Organism
metabolism reaction is the first step in the lysine biosynthetic pathway through alpha-aminoadipate Thermus thermophilus