Conformational analysis of the riboflavin-responsive ETF:QO-p.Pro456Leu variant associated with mild multiple acyl-CoA dehydrogenase deficiency.

Autor: Lucas TG; Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal., Henriques BJ; Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal., Gomes CM; Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal. Electronic address: cmgomes@fc.ul.pt.
Jazyk: angličtina
Zdroj: Biochimica et biophysica acta. Proteins and proteomics [Biochim Biophys Acta Proteins Proteom] 2020 Jun; Vol. 1868 (6), pp. 140393. Date of Electronic Publication: 2020 Feb 19.
DOI: 10.1016/j.bbapap.2020.140393
Abstrakt: Multiple-CoA dehydrogenase deficiency (MADD) is an inborn disorder of fatty acid and amino acid metabolism caused by mutations in the genes encoding for human electron transfer flavoprotein (ETF) and its partner electron transfer flavoprotein:ubiquinone oxidoreductase (ETF:QO). Albeit a rare disease, extensive newborn screening programs contributed to a wider coverage of MADD genotypes. However, the impact of non-lethal mutations on ETF:QO function remains scarcely understood from a structural perspective. To this end, we here revisit the relatively common MADD mutation ETF:QO-p.Pro456Leu, in order to clarify how it affects enzyme structure and folding. Given the limitation in recombinant expression of human ETF:QO, we resort to its bacterial homologue from Rhodobacter sphaeroides (Rs), in which the corresponding mutation (p.Pro389Leu) was inserted. The in vitro biochemical and biophysical investigations of the Rs ETF:QO-p.Pro389Leu variant showed that, while the mutation does not significantly affect the protein α/β fold, it introduces some plasticity on the tertiary structure and within flavin interactions. Indeed, in the p.Pro389Leu variant, FAD exhibits a higher thermolability during thermal denaturation and a faster rate of release in temperature-induced dissociation experiments, in comparison to the wild type. Therefore, although this clinical mutation occurs in the ubiquinone domain, its effect likely propagates to the nearby FAD binding domain, probably influencing electron transfer and redox potentials. Overall, our results provide a molecular rational for the decreased enzyme activity observed in patients and suggest that compromised FAD interactions in ETF:QO might account for the known riboflavin responsiveness of this mutation.
Competing Interests: Declaration of Competing Interest Tânia Lucas, Bárbara Henriques and Cláudio Gomes declare that they have no conflict of interest.
(Copyright © 2020 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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