NMR structural and biophysical analysis of the disease-linked inner mitochondrial membrane protein MPV17.
J. Mol. Biol. 433:167098 (2021)
MPV17 is an integral inner mitochondrial membrane protein, whose loss-of-function is linked to the hepatocerebral form of the mitochondrial-DNA-depletion syndrome, leading to a tissue-specific reduction of mitochondrial DNA and organ failure in infants. Several disease-causing mutations in MPV17 have been identified and earlier studies with reconstituted protein suggest that MPV17 forms a high conductivity channel in the membrane. However, the molecular and structural basis of the MPV17 functionality remain only poorly understood. In order to make MPV17 accessible to high-resolution structural studies, we here present an efficient protocol for its high-level production in E. coli and refolding into detergent micelles. Using biophysical and NMR methods, we show that refolded MPV17 in detergent micelles adopts a compact structure consisting of six membrane-embedded α-helices. Furthermore, we demonstrate that MPV17 forms oligomers in a lipid bilayer that are further stabilized by disulfide-bridges. In line with these findings, MPV17 could only be inserted into lipid nanodiscs of 8-12 nm in diameter if intrinsic cysteines were either removed by mutagenesis or blocked by chemical modification. Using this nanodisc reconstitution approach, we could show that disease-linked mutations in MPV17 abolish its oligomerization properties in the membrane. These data suggest that, induced by oxidative stress, MPV17 can alter its oligomeric state from a properly folded monomer to a disulfide-stabilized oligomeric pore which might be required for the transport of metabolic DNA precursors into the mitochondrial matrix to compensate for the damage caused by reactive oxygen species.
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Publikationstyp
Artikel: Journalartikel
Dokumenttyp
Wissenschaftlicher Artikel
Typ der Hochschulschrift
Herausgeber
Schlagwörter
Dynamics ; Membrane Protein Stability ; Mitochondrial Diseases ; Nanodiscs ; Reactive Oxygen Species; Phospholipid-bilayer Nanodiscs; Kidney-disease; Gene Mpv17; Encodes; Channel; Sym1; Reconstruction; Resolution; Ortholog
Keywords plus
Sprache
englisch
Veröffentlichungsjahr
2021
Prepublished im Jahr
HGF-Berichtsjahr
2021
ISSN (print) / ISBN
0022-2836
e-ISSN
1089-8638
ISBN
Bandtitel
Konferenztitel
Konferzenzdatum
Konferenzort
Konferenzband
Quellenangaben
Band: 433,
Heft: 15,
Seiten: ,
Artikelnummer: 167098
Supplement: ,
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Verlag
Elsevier
Verlagsort
24-28 Oval Rd, London Nw1 7dx, England
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0000-00-00
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Gutachter
Prüfer
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0000-00-00
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0000-00-00
Anmelder/Inhaber
weitere Inhaber
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Priorität
Begutachtungsstatus
Peer reviewed
POF Topic(s)
30203 - Molecular Targets and Therapies
Forschungsfeld(er)
Enabling and Novel Technologies
PSP-Element(e)
G-503094-001
Förderungen
Center for Integrated Protein Science Munich (CIPSM)
European Union
Technical University of Munich, Institute for Advanced Study - German Excellence Initiative
Helmholtz Society
Copyright
Erfassungsdatum
2021-07-19