Your browser doesn't support javascript.
loading
Biochemical, structural, and computational analyses of two new clinically identified missense mutations of ALDH7A1.
Korasick, David A; Buckley, David P; Palpacelli, Alessandra; Cursio, Ida; Cesaroni, Elisabetta; Cheng, Jianlin; Tanner, John J.
Affiliation
  • Korasick DA; Department of Biochemistry, University of Missouri, Columbia, MO, 65211, United States.
  • Buckley DP; Department of Biochemistry, University of Missouri, Columbia, MO, 65211, United States.
  • Palpacelli A; Pediatric Unit, Pediatric Hospital G. Salesi, United Hospitals of Marche, Italy.
  • Cursio I; Child Neurology and Psychiatric Unit, Pediatric Hospital G. Salesi, United Hospitals of Marche, Ancona, Italy.
  • Cesaroni E; Child Neurology and Psychiatric Unit, Pediatric Hospital G. Salesi, United Hospitals of Marche, Ancona, Italy.
  • Cheng J; Department of Electrical Engineering and Computer Science, University of Missouri, Columbia, MO, 65211, United States.
  • Tanner JJ; Department of Biochemistry, University of Missouri, Columbia, MO, 65211, United States; Department of Chemistry, University of Missouri, Columbia, MO, 65211, United States. Electronic address: tannerjj@missouri.edu.
Chem Biol Interact ; 394: 110993, 2024 May 01.
Article in En | MEDLINE | ID: mdl-38604394
ABSTRACT
Aldehyde dehydrogenase 7A1 (ALDH7A1) catalyzes a step of lysine catabolism. Certain missense mutations in the ALDH7A1 gene cause pyridoxine dependent epilepsy (PDE), a rare autosomal neurometabolic disorder with recessive inheritance that affects almost 165,000 live births and is classically characterized by recurrent seizures from the neonatal period. We report a biochemical, structural, and computational study of two novel ALDH7A1 missense mutations that were identified in a child with rare recurrent seizures from the third month of life. The mutations affect two residues in the oligomer interfaces of ALDH7A1, Arg134 and Arg441 (Arg162 and Arg469 in the HGVS nomenclature). The corresponding enzyme variants R134S and R441C (p.Arg162Ser and p.Arg469Cys in the HGVS nomenclature) were expressed in Escherichia coli and purified. R134S and R441C have 10,000- and 50-fold lower catalytic efficiency than wild-type ALDH7A1, respectively. Sedimentation velocity analytical ultracentrifugation shows that R134S is defective in tetramerization, remaining locked in a dimeric state even in the presence of the tetramer-inducing coenzyme NAD+. Because the tetramer is the active form of ALDH7A1, the defect in oligomerization explains the very low catalytic activity of R134S. In contrast, R441C exhibits wild-type oligomerization behavior, and the 2.0 Å resolution crystal structure of R441C complexed with NAD+ revealed no obvious structural perturbations when compared to the wild-type enzyme structure. Molecular dynamics simulations suggest that the mutation of Arg441 to Cys may increase intersubunit ion pairs and alter the dynamics of the active site gate. Our biochemical, structural, and computational data on two novel clinical variants of ALDH7A1 add to the complexity of the molecular determinants underlying pyridoxine dependent epilepsy.
Subject(s)
Key words

Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Mutation, Missense / Aldehyde Dehydrogenase Limits: Humans / Infant / Male Language: En Journal: Chem Biol Interact Year: 2024 Document type: Article Affiliation country: United States

Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Mutation, Missense / Aldehyde Dehydrogenase Limits: Humans / Infant / Male Language: En Journal: Chem Biol Interact Year: 2024 Document type: Article Affiliation country: United States