W196 and the ß -Hairpin Motif Modulate the Redox Switch of Conformation and the Biomolecular Interaction Network of the Apoptosis-Inducing Factor

Romero-Tamayo, S. ; Laplaza, R. ; Velazquez-Campoy, A. (Universidad de Zaragoza) ; Villanueva, R. ; Medina, M. (Universidad de Zaragoza) ; Ferreira, P. (Universidad de Zaragoza)

Resumen: The human apoptosis-inducing factor (hAIF) is a moonlight flavoprotein involved in mitochondrial respiratory complex assembly and caspase-independent programmed cell death. These functions might be modulated by its redox-linked structural transition that enables hAIF to act as a NAD(H/+) redox sensor. Upon reduction with NADH, hAIF undergoes a conformational reorganization in two specific insertions - the flexible regulatory C-loop and the 190-202 ß-harpin - promoting protein dimerization and the stabilization of a long-life charge transfer complex (CTC) that modulates its monomer-dimer equilibrium and its protein interaction network in healthy mitochondria. In this regard, here, we investigated the precise function of the ß-hairpin in the AIF conformation landscape related to its redox mechanism, by analyzing the role played by W196, a key residue in the interaction of this motif with the regulatory C-loop. Mutations at W196 decrease the compactness and stability of the oxidized hAIF, indicating that the ß-hairpin and C-loop coupling contribute to protein stability. Kinetic studies complemented with computational simulations reveal that W196 and the ß-hairpin conformation modulate the low efficiency of hAIF as NADH oxidoreductase, contributing to configure its active site in a noncompetent geometry for hydride transfer and to stabilize the CTC state by enhancing the affinity for NAD+. Finally, the ß-hairpin motif contributes to define the conformation of AIF's interaction surfaces with its physiological partners. These findings improve our understanding on the molecular basis of hAIF''s cellular activities, a crucial aspect for clarifying its associated pathological mechanisms and developing new molecular therapies.

Idioma: Inglés

DOI: 10.1155/2021/6673661

Año: 2021

Publicado en: Oxidative Medicine and Cellular Longevity 2021 (2021), 6673661 [19 pp]
ISSN: 1942-0900

Factor impacto JCR: 7.31 (2021)

Categ. JCR: CELL BIOLOGY rank: 55 / 195 = 0.282 (2021) - Q2 - T1

Factor impacto CITESCORE: 9.3 - Medicine (Q1) - Biochemistry, Genetics and Molecular Biology (Q1)

Factor impacto SCIMAGO: 1.233 - Biochemistry (Q1) - Medicine (miscellaneous) (Q1) - Cell Biology (Q1)

Financiación: info:eu-repo/grantAgreement/ES/DGA/ARAID
Financiación: info:eu-repo/grantAgreement/ES/DGA-FEDER/E35-20R
Financiación: info:eu-repo/grantAgreement/ES/MICINN-AEI/PID2019-103901GB-I00
Financiación: info:eu-repo/grantAgreement/ES/MINECO-AEI-FEDER/BIO2016-75183-P

Tipo y forma: Article (Published version)

Área (Departamento): Área Bioquímica y Biolog.Mole. (Dpto. Bioq.Biolog.Mol. Celular)