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Literature summary for 2.4.2.8 extracted from

  • Chen, Q.; Liang, Y.; Su, X.; Gu, X.; Zheng, X.; Luo, M.
    Alternative IMP binding in feedback inhibition of hypoxanthine-guanine phosphoribosyltransferase from Thermoanaerobacter tengcongensis (2005), J. Mol. Biol., 348, 1199-1210.
    View publication on PubMed

Crystallization (Commentary)

Crystallization (Comment) Organism
free enzyme or enzyme complexed with IMP, hanging drop vapour diffusion method, 20°C, 10 mg/ml protein in 20 Tris-HCl, pH 7.4, mixed with a molar excess of IMP, 0.001 ml protein solution mixed with equal volume of reservoir solution containing 0.2 M magnesium acetate tetrahydrate, 0.1 M sodium cacodylate, pH 6.5, 12% w/v PEG 4000, or protein solution with 1 mM IMP mixed with reservoir solution containing 15% PEG 8000, 0.1 M sodium cacodylate, pH 6.5, 0.2 M magnesium acetate tetrahydrate, X-ray diffraction structure determination and analysis at 2.2-2.5 A resolution Caldanaerobacter subterraneus subsp. tengcongensis

Inhibitors

Inhibitors Comment Organism Structure
IMP feedback inhibition, competitive versus 5-phospho-alpha-D-ribose 1-diphosphate, binding mode Caldanaerobacter subterraneus subsp. tengcongensis

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.133
-
5-phospho-alpha-D-ribose 1-diphosphate pH 7.4, 12 mM MgCl2 Caldanaerobacter subterraneus subsp. tengcongensis
0.327
-
5-phospho-alpha-D-ribose 1-diphosphate pH 7.4, 12 mM MgCl2, in presence of 0.05 mM IMP Caldanaerobacter subterraneus subsp. tengcongensis

Metals/Ions

Metals/Ions Comment Organism Structure
Mg2+ required for binding of 5-phospho-alpha-D-ribose 1-diphosphate, binding via side chains of Glu101 and Asp102 and water molecules in the apoenzyme, binding site structure Caldanaerobacter subterraneus subsp. tengcongensis

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
guanine + 5-phospho-alpha-D-ribose 1-diphosphate Caldanaerobacter subterraneus subsp. tengcongensis
-
GMP + diphosphate
-
?
hypoxanthine + 5-phospho-alpha-D-ribose 1-diphosphate Caldanaerobacter subterraneus subsp. tengcongensis
-
IMP + diphosphate
-
?

Organism

Organism UniProt Comment Textmining
Caldanaerobacter subterraneus subsp. tengcongensis
-
-
-

Reaction

Reaction Comment Organism Reaction ID
IMP + diphosphate = hypoxanthine + 5-phospho-alpha-D-ribose 1-diphosphate substrate binding structure and mechanism, a non-proline cis-peptide may be essential for activity Caldanaerobacter subterraneus subsp. tengcongensis

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
guanine + 5-phospho-alpha-D-ribose 1-diphosphate
-
Caldanaerobacter subterraneus subsp. tengcongensis GMP + diphosphate
-
?
hypoxanthine + 5-phospho-alpha-D-ribose 1-diphosphate
-
Caldanaerobacter subterraneus subsp. tengcongensis IMP + diphosphate
-
?
hypoxanthine + 5-phospho-alpha-D-ribose 1-diphosphate binding mechanism and structure of IMP occupying the diphosphate site, overview Caldanaerobacter subterraneus subsp. tengcongensis IMP + diphosphate
-
?
additional information the conformation of the flexible loop, containing a 3-10 helix and a unique double serine repeat, is important for substrate binding and activation of the enzyme Caldanaerobacter subterraneus subsp. tengcongensis ?
-
?

Subunits

Subunits Comment Organism
tetramer active enzyme form, subunit A composition, overview Caldanaerobacter subterraneus subsp. tengcongensis

Synonyms

Synonyms Comment Organism
HGPRT
-
Caldanaerobacter subterraneus subsp. tengcongensis
hypoxanthine-guanine phosphoribosyltransferase
-
Caldanaerobacter subterraneus subsp. tengcongensis

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
4.26
-
5-phospho-alpha-D-ribose 1-diphosphate pH 7.4, 12 mM MgCl2 Caldanaerobacter subterraneus subsp. tengcongensis

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
7.4
-
assay at Caldanaerobacter subterraneus subsp. tengcongensis

Ki Value [mM]

Ki Value [mM] Ki Value maximum [mM] Inhibitor Comment Organism Structure
0.045
-
IMP pH 7.4, 12 mM MgCl2, versus 5-phospho-alpha-D-ribose 1-diphosphate Caldanaerobacter subterraneus subsp. tengcongensis