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Literature summary for 1.3.5.1 extracted from

  • Maklashina, E.; Rajagukguk, S.; McIntire, W.S.; Cecchini, G.
    Mutation of the heme axial ligand of Escherichia coli succinate-quinone reductase: Implications for heme ligation in mitochondrial complex II from yeast (2010), Biochim. Biophys. Acta, 1797, 747-754.
    View publication on PubMedView publication on EuropePMC

Cloned(Commentary)

Cloned (Comment) Organism
expressed in Escherichia coli strain DW35 Escherichia coli

Protein Variants

Protein Variants Comment Organism
H71C role of a Cys residue in Escherichia coli SdhD for heme b coordination is examined. H71C mutant is created to mimic the TyrCys motif found in yeast Sdh4p. Mutant H71C results in a protein that retains penta-coordinated heme b indicating that Cys is not able to provide coordination for the heme in Escherichia coli SQR even in its optimal structural position. Km (ubiquinone): 0.012 mM compared to 0.0025 mM wild-type. H71C and Y71C72 mutants show higher phenazine ethosulfate or ubiquinone reductase activities than mutant H71Y. Mutant H71C retains 43% of ubiquinone reductase activity compared to wild-type SQR, quinone reductase activity is impaired to a greater extent than its succinate-oxidase activity measured with phenazine ethosulfate Escherichia coli
H71Y mutant lacks heme. Km (ubiquinone): 0.01 mM compared to 0.0025 mM wild-type, lower ubiquinone or phenazine ethosulfate reductase activity compared to mutant H71C or double mutant H71Y/A72C Escherichia coli
H71Y/A72C role of a Cys residue in Escherichia coli SdhD for heme b coordination is examined. H71C mutant is created to mimic the TyrCys motif found in yeast Sdh4p. Double mutant assembles within the membrane but without heme, and it retains the ability to reduce quinone. Km (ubiquinone): 0.013 mM compared to 0.0025 mM wild-type. H71C and Y71C72 mutants show higher phenazine ethosulfate or ubiquinone reductase activities than mutant H71Y. The Y71C72 double mutant shows significant improvement in its activity compared to H71Y or H71C Escherichia coli

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.0025
-
ubiquinone wild-type SQR Escherichia coli
0.01
-
ubiquinone mutant H71Y Escherichia coli
0.012
-
ubiquinone mutant H71Y Escherichia coli
0.013
-
ubiquinone mutant H71Y/A72C Escherichia coli

Localization

Localization Comment Organism GeneOntology No. Textmining

Organism

Organism UniProt Comment Textmining
Escherichia coli
-
-
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
succinate + phenazine ethosulfate
-
Escherichia coli fumarate + reduced phenazine ethosulfate
-
?
succinate + ubiquinone
-
Escherichia coli fumarate + ubiquinol
-
?

Synonyms

Synonyms Comment Organism
SdhD succinate dehydrogenase subunit that also coordinate the low spin hexa-coordinated heme b Escherichia coli
SQR
-
Escherichia coli

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
30
-
assay at Escherichia coli

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
8
-
assay at Escherichia coli

Cofactor

Cofactor Comment Organism Structure
flavin adenine dinucleotide
-
Escherichia coli