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Literature summary for 1.7.1.13 extracted from

  • Jung, J.; Czabany, T.; Wilding, B.; Klempier, N.; Nidetzky, B.
    Kinetic analysis and probing with substrate analogues of the reaction pathway of the nitrile reductase QueF from Escherichia coli (2016), J. Biol. Chem., 291, 25411-25426 .
    View publication on PubMedView publication on EuropePMC

Protein Variants

Protein Variants Comment Organism
C190A mutation in catalytic residue, no evidence of covalent binding of substrate preQ0. Mutant displays proton uptake Escherichia coli

Inhibitors

Inhibitors Comment Organism Structure
7-formyl-7-deazaguanine carbonyl analogue of the imine intermediate, recognized by QueF as weak ligand for binding but not as substrate for reduction or oxidation Escherichia coli

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.001
-
7-cyano-7-carbaguanine below 1 microM, pH 7.5, 25°C Escherichia coli
0.0078
-
NADPH pH 7.5, 25°C Escherichia coli
0.05
-
7-cyano-7-carba-2-deaminoguanine pH 7.5, 25°C Escherichia coli

Organism

Organism UniProt Comment Textmining
Escherichia coli
-
-
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
7-cyano-7-carba-2-deaminoguanine + 2 NADPH + 2 H+
-
Escherichia coli 7-aminomethyl-7-carba-2-deaminoguanine + 2 NADP+
-
?
7-cyano-7-carbaguanine + 2 NADPH + 2 H+
-
Escherichia coli 7-aminomethyl-7-carbaguanine + 2 NADP+
-
?
additional information QueF binds substrate preQ0 in a strongly exothermic process (DeltaH 80.3 kJ/mol) whereby the thioimide adduct is formed with half-of-the-sites reactivity in the homodimeric enzyme. Both steps of preQ0 reduction involve transfer of the 4-pro-R-hydrogen from NADPH. They proceed about 4-7fold more slowly than trapping of the enzyme-bound preQ0 as covalent thioimide and are mainly rate-limiting for the enzyme's kcat Escherichia coli ?
-
?

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
0.12
-
7-cyano-7-carbaguanine pH 7.5, 25°C Escherichia coli
0.14
-
7-cyano-7-carba-2-deaminoguanine pH 7.5, 25°C Escherichia coli

Cofactor

Cofactor Comment Organism Structure
NADPH
-
Escherichia coli