Biochemical characterization of human D-2-hydroxyglutarate dehydrogenase and two disease related variants reveals the molecular cause of D-2-hydroxyglutaric aciduria

Publication date: Available online 23 July 2019Source: Biochimica et Biophysica Acta (BBA) - Proteins and ProteomicsAuthor(s): Marina Toplak, Julia Brunner, Julia Schmidt, Peter MacherouxAbstractD-2-hydroxyglutaric aciduria is a neurometabolic disorder, characterized by the accumulation of D-2-hydroxyglutarate (D-2HG) in human mitochondria. Increased levels of D-2HG are detected in humans exhibiting point mutations in the genes encoding isocitrate dehydrogenase, citrate carrier, the electron transferring flavoprotein (ETF) and its downstream electron acceptor ETF-ubiquinone oxidoreductase or D-2-hydroxyglutarate dehydrogenase (hD2HGDH). However, while the pathogenicity of several amino acid replacements in the former four proteins has been studied extensively, not much is known about the effect of certain point mutations on the biochemical properties of hD2HGDH.Therefore, we recombinantly produced wild type hD2HGDH as well as two recently identified disease-related variants (hD2HGDH-I147S and -V444A) and performed their detailed biochemical characterization. We could show that hD2HGDH is a FAD dependent protein, which is able to catalyze the oxidation of D-2HG and D-lactate to α-ketoglutarate and pyruvate, respectively. The two variants were obtained as apo-proteins and were thus catalytically inactive. The addition of FAD failed to restore enzymatic activity of the variants, indicating that the cofactor binding site is compromised by the single amino acid replacements. Furt...
Source: Biochimica et Biophysica Acta (BBA) Proteins and Proteomics - Category: Biochemistry Source Type: research