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Sperl, L.E.* ; Hagn, F.

NMR structural and biophysical analysis of the disease-linked inner mitochondrial membrane protein MPV17.

J. Mol. Biol. 433:167098 (2021)
Postprint DOI PMC
Open Access Green
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
Korrespondenzautor
Schlagwörter Dynamics ; Membrane Protein Stability ; Mitochondrial Diseases ; Nanodiscs ; Reactive Oxygen Species; Phospholipid-bilayer Nanodiscs; Kidney-disease; Gene Mpv17; Encodes; Channel; Sym1; Reconstruction; Resolution; Ortholog
ISSN (print) / ISBN 0022-2836
e-ISSN 1089-8638
Zeitschrift Journal of Molecular Biology
Quellenangaben Band: 433, Heft: 15, Seiten: , Artikelnummer: 167098 Supplement: ,
Verlag Elsevier
Verlagsort 24-28 Oval Rd, London Nw1 7dx, England
Nichtpatentliteratur Publikationen
Begutachtungsstatus Peer reviewed
Institut(e) Institute of Structural Biology (STB)
Förderungen Center for Integrated Protein Science Munich (CIPSM)
European Union
Technical University of Munich, Institute for Advanced Study - German Excellence Initiative
Helmholtz Society