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Literature summary for 1.17.1.4 extracted from

  • Schumann, S.; Saggu, M.; Moeller, N.; Anker, S.D.; Lendzian, F.; Hildebrandt, P.; Leimkuehler, S.
    The mechanism of assembly and cofactor insertion into Rhodobacter capsulatus xanthine dehydrogenase (2008), J. Biol. Chem., 283, 16602-16611.
    View publication on PubMed
Search for more literature for 1.17.1.4

Cloned(Commentary)

Cloned (Comment) Organism
C-terminally His6-tagged wild-type and mutant XDHs expression in Escherichia coli strain TP1000 Rhodobacter capsulatus

Protein Variants

Protein Variants Comment Organism
C134A/C136A site-directed mutagenesis, an inactive subunit A mutant Rhodobacter capsulatus
C44A/C47A site-directed mutagenesis, an instable subunit A mutant that cannot be purified Rhodobacter capsulatus
E220R/D517R site-directed mutagenesis, a subunit B mutant that is mainly dimeris incontrast to the tetrameric wild-type enzyme, inactive mutant Rhodobacter capsulatus
Q102A site-directed mutagenesis, a subunit A mutant that shows altered metal content and reduced KM and Kcat with xanthine compared to the wild-type enzyme Rhodobacter capsulatus
Q102G site-directed mutagenesis, a subunit A mutant that shows altered metal content and reduced KM and Kcat with xanthine compared to the wild-type enzyme Rhodobacter capsulatus

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.0227
-
 xanthine pH 7.8, 25°C, mutant Q102G, with NAD+ Rhodobacter capsulatus
0.0293
-
 xanthine pH 7.8, 25°C, mutant Q102A, with NAD+ Rhodobacter capsulatus
0.0328
-
 NAD+ pH 7.8, 25°C, wild-type enzyme Rhodobacter capsulatus
0.0373
-
 NAD+ pH 7.8, 25°C, mutant Q102G Rhodobacter capsulatus
0.0402
-
 NAD+ pH 7.8, 25°C, mutant Q102A Rhodobacter capsulatus
0.0442
-
 xanthine pH 7.8, 25°C, wild-type enzyme, with NAD+ Rhodobacter capsulatus
0.0809
-
 DCPIP pH 7.8, 25°C, mutants Q102A and Q102G Rhodobacter capsulatus
0.0823
-
 DCPIP pH 7.8, 25°C, wild-type enzyme Rhodobacter capsulatus

Metals/Ions

Metals/Ions Comment Organism Structure
Iron the enzyme is a molybdo-flavoprotein, the enzyme tetramer contains two [2Fe-2S] clusters Rhodobacter capsulatus
Molybdenum the enzyme is molybdo-flavoprotein, one cofactor molecule per enzyme tetramer Rhodobacter capsulatus

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
xanthine + NAD+ + H2O Rhodobacter capsulatus
-
 urate + NADH + H+
-
 ?

Organism

Organism UniProt Comment Textmining
Rhodobacter capsulatus
-
-
-

Posttranslational Modification

Posttranslational Modification Comment Organism
flavoprotein
-
 Rhodobacter capsulatus

Purification (Commentary)

Purification (Comment) Organism
recombinant His-tagged wild-type and mutant XDHs from Escherichia coli strain TP1000 by nickel affinity and anion exchange chromatography, followed by ultrafiltration and gel filtration Rhodobacter capsulatus

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
xanthine + DCIP + H2O
-
 Rhodobacter capsulatus urate + reduced DCIP
-
 ?
xanthine + NAD+ + H2O
-
 Rhodobacter capsulatus urate + NADH + H+
-
 ?

Subunits

Subunits Comment Organism
heterotetramer (alphabeta)2 structure, mechanism of assembly and cofactor insertion on two different polypeptides: dimerization of the (alphabeta) subunits has to precede molybdenum cofactor insertion, the two subunits act independently without cooperativity, incomplete assembly of FeSI impairs the formation of the XDH (alphabeta)2 heterotetramer and, thus, insertion of the molybdenum cofactor into the enzyme, overview Rhodobacter capsulatus

Synonyms

Synonyms Comment Organism
XDH
-
 Rhodobacter capsulatus

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
25
-
 assay at Rhodobacter capsulatus

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
31.6
-
 xanthine pH 7.8, 25°C, mutant Q102G, with DCIP Rhodobacter capsulatus
34.3
-
 xanthine pH 7.8, 25°C, mutant Q102A, with DCIP Rhodobacter capsulatus
39.5
-
 xanthine pH 7.8, 25°C, mutant Q102A, with NAD+ Rhodobacter capsulatus
40.6
-
 xanthine pH 7.8, 25°C, mutant Q102G, with NAD+ Rhodobacter capsulatus
66.1
-
 xanthine pH 7.8, 25°C, wild-type enzyme, with DCIP Rhodobacter capsulatus
77.5
-
 xanthine pH 7.8, 25°C, wild-type enzyme, with NAD+ Rhodobacter capsulatus

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
7.5 7.8 assay at Rhodobacter capsulatus

Cofactor

Cofactor Comment Organism Structure
molybdenum cofactor binding involves residues GluB730, GlnA102, CysA103, CysA106, CysA134, and CysA13 of the alpha and beta subunits Rhodobacter capsulatus
NAD+
-
 Rhodobacter capsulatus
[2Fe-2S] cluster
-
 Rhodobacter capsulatus