Structural Insights into the Coenzyme Mediated Monomer鈥揇imer Transition of the Pro-Apoptotic Apoptosis Inducing Factor

详细信息    查看全文

• 作者：Patricia Ferreira ; Raquel Villanueva ; Marta Mart铆nez-J煤lvez ; Beatriz Herguedas ; Carlos Marcuello ; Patricio Fernandez-Silva ; Lauriane Cabon ; Juan A. Hermoso ; Anabel Lostao ; Santos A. Susin ; Milagros Medina
• 刊名：Biochemistry
• 出版年：2014
• 出版时间：July 1, 2014
• 年：2014
• 卷：53
• 期：25
• 页码：4204-4215
• 全文大小：610K
• ISSN：1520-4995

文摘

The apoptosis-inducing factor (AIF) is a mitochondrial-flavoprotein that, after cell death induction, is distributed to the nucleus to mediate chromatinolysis. In mitochondria, AIF is present in a monomer鈥揹imer equilibrium that after reduction by NADH gets displaced toward the dimer. The crystal structure of the human AIF (hAIF):NAD(H)-bound dimer revealed one FAD and, unexpectedly, two NAD(H) molecules per protomer. A 1:2 hAIF:NAD(H) binding stoichiometry was additionally confirmed in solution by using surface plasmon resonance. The here newly discovered NAD(H)-binding site includes residues mutated in human disorders, and accommodation of the coenzyme in it requires restructuring of a hAIF portion within the 509鈥?60 apoptogenic segment. Disruption of interactions at the dimerization surface by production of the hAIF E413A/R422A/R430A mutant resulted in a nondimerizable variant considerably less efficiently stabilizing charge-transfer complexes upon coenzyme reduction than WT hAIF. These data reveal that the coenzyme-mediated monomer鈥揹imer transition of hAIF modulates the conformation of its C-terminal proapoptotic domain, as well as its mechanism as reductase. These observations suggest that both the mitochondrial and apoptotic functions of hAIF are interconnected and coenzyme controlled: a key information in the understanding of the physiological role of AIF in the cellular life and death cycle.