7PSC

Crystal structure of the disease-causing I358T mutant of the human dihydrolipoamide dehydrogenase

Summary for 7PSC

• Entry DOI: 10.2210/pdb7psc/pdb
• Descriptor: Dihydrolipoyl dehydrogenase, mitochondrial, FLAVIN-ADENINE DINUCLEOTIDE, 2-[BIS-(2-HYDROXY-ETHYL)-AMINO]-2-HYDROXYMETHYL-PROPANE-1,3-DIOL, ... (4 entities in total)
• Functional Keywords: lipoamide dehydrogenase, pathogenic mutation, e3 deficiency, alpha-ketoglutarate dehydrogenase complex, 2-oxoglutarate dehydrogenase complex, pyruvate dehydrogenase complex, oxidoreductase
• Biological source: Homo sapiens (Human)
• Total number of polymer chains: 2
• Total formula weight: 107658.29

Authors

Nemes-Nikodem, E.,Szabo, E.,Zambo, Z.,Vass, K.R.,Taberman, H.,Torocsik, B.,Weiss, M.S.,Adam-Vizi, V.,Ambrus, A. (deposition date: 2021-09-22, release date: 2023-04-05, Last modification date: 2024-11-13)

Primary citation

Szabo, E.,Nemes-Nikodem, E.,Vass, K.R.,Zambo, Z.,Zrupko, E.,Torocsik, B.,Ozohanics, O.,Nagy, B.,Ambrus, A.
Structural and Biochemical Investigation of Selected Pathogenic Mutants of the Human Dihydrolipoamide Dehydrogenase.
Int J Mol Sci, 24:-, 2023

PubMed Abstract: Clinically relevant disease-causing variants of the human dihydrolipoamide dehydrogenase (hLADH, hE3), a common component of the mitochondrial α-keto acid dehydrogenase complexes, were characterized using a multipronged approach to unravel the molecular pathomechanisms that underlie hLADH deficiency. The G101del and M326V substitutions both reduced the protein stability and triggered the disassembly of the functional/obligate hLADH homodimer and significant FAD losses, which altogether eventually manifested in a virtually undetectable catalytic activity in both cases. The I12T-hLADH variant proved also to be quite unstable, but managed to retain the dimeric enzyme form; the LADH activity, both in the and catalytic directions and the affinity for the prosthetic group FAD were both significantly compromised. None of the above three variants lent themselves to an in-depth structural analysis via X-ray crystallography due to inherent protein instability. Crystal structures at 2.89 and 2.44 Å resolutions were determined for the I318T- and I358T-hLADH variants, respectively; structure analysis revealed minor conformational perturbations, which correlated well with the residual LADH activities, in both cases. For the dimer interface variants G426E-, I445M-, and R447G-hLADH, enzyme activities and FAD loss were determined and compared against the previously published structural data.

PubMed: 37446004
DOI: 10.3390/ijms241310826

Experimental method

X-RAY DIFFRACTION (2.436 Å)