Defining NADH-Driven Allostery Regulating Apoptosis-Inducing Factor.
Apoptosis-inducing factor (AIF) is critical for mitochondrial respiratory complex biogenesis and for mediating necroptotic parthanatos; these functions are seemingly regulated by enigmatic allosteric switching driven by NADH charge-transfer complex (CTC) formation. Here, we define molecular pathways linking AIF's active site to allosteric switching regions by characterizing dimer-permissive mutants using small-angle X-ray scattering (SAXS) and crystallography and by probing AIF-CTC communication networks using molecular dynamics simulations. Collective results identify two pathways propagating allostery from the CTC active site: (1) active-site H454 links to S480 of AIF's central β-strand to modulate a hydrophobic border at the dimerization interface, and (2) an interaction network links AIF's FAD cofactor, central β-strand, and Cβ-clasp whereby R529 reorientation initiates C-loop release during CTC formation. This knowledge of AIF allostery and its flavoswitch mechanism provides a foundation for biologically understanding and biomedically controlling its participation in mitochondrial homeostasis and cell death.
Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA; Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA. Electronic address: cabrosey@mdanderson.org.
Chris A
CA
Brosey
Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
Chris
C
Ho
Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
Winnie Z
WZ
Long
Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
Sukrit
S
Singh
MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Kathryn
K
Burnett
MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA 95064, USA.
Greg L
GL
Hura
Molecular Biology Consortium, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Jay C
JC
Nix
Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
Gregory R
GR
Bowman
Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
Tom
T
Ellenberger
MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA. Electronic address: jtainer@mdanderson.org.
John A
JA
Tainer
D000494:Allosteric Regulation; D051033:Apoptosis Inducing Factor / Q000737:chemistry* / Q000378:metabolism*; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D019281:Dimerization; D006801:Humans; D008958:Models, Molecular; D009243:NAD / Q000378:metabolism*; D017433:Protein Structure, Secondary; D053838:Scattering, Small Angle; D014961:X-Ray Diffraction
C494829:AIFM1 protein, human; D051033:Apoptosis Inducing Factor; D009243:NAD
SAXS; X-ray crystallography; allostery; apoptosis-inducing factor; charge-transfer complex; flavoswitch; mitochondrial homeostasis; molecular dynamics; parthanatos