Structural and functional fingerprint of the mitochondrial ATP-binding cassette transporter Mdl1 from Saccharomyces cerevisiae
- The ATP-binding cassette half-transporter Mdl1 from Saccharomyces cerevisiae has been proposed to be involved in the quality control of misassembled respiratory chain complexes by exporting degradation products generated by the m-AAA proteases from the matrix. Direct functional or structural data of the transport complex are, however, not known so far. After screening expression in various hosts, Mdl1 was overexpressed 100-fold to 1% of total mitochondrial membrane protein in S. cerevisiae. Based on detergent screens, Mdl1 was solubilized and purified to homogeneity. Mdl1 showed a high binding affinity for MgATP (Kd = 0.26 μm) and an ATPase activity with a Km of 0.86 mm (Hill coefficient of 0.98) and a turnover rate of 2.6 ATP/s. Mutagenesis of the conserved glutamate downstream of the Walker B motif (E599Q) or the conserved histidine of the H-loop (H631A) abolished ATP hydrolysis, whereas ATP binding was not affected. Mdl1 reconstituted into liposomes showed an ATPase activity similar to the solubilized complex. By single particle electron microscopy, a first three-dimensional structure of the mitochondrial ATP-binding cassette transporter was derived at 2.3-nm resolution, revealing a homodimeric complex in an open conformation.
Verfasserangaben: | Matthias HofackerGND, Simone GompfGND, Ariane ZutzGND, Chiara Presenti, Winfried Haase, Chris van der DoesGND, Kirstin ModelGND, Robert TampéORCiDGND |
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URN: | urn:nbn:de:hebis:30:3-763074 |
DOI: | https://doi.org/10.1074/jbc.M609899200 |
ISSN: | 0021-9258 |
Pubmed-Id: | https://pubmed.ncbi.nlm.nih.gov/17150958 |
Titel des übergeordneten Werkes (Englisch): | Journal of biological chemistry |
Verlag: | American Society for Biochemistry and Molecular Biology Publications |
Verlagsort: | Bethesda, Md |
Dokumentart: | Wissenschaftlicher Artikel |
Sprache: | Englisch |
Datum der Veröffentlichung (online): | 04.01.2021 |
Jahr der Erstveröffentlichung: | 2007 |
Veröffentlichende Institution: | Universitätsbibliothek Johann Christian Senckenberg |
Datum der Freischaltung: | 09.11.2023 |
Jahrgang: | 282 |
Ausgabe / Heft: | 6 |
Seitenzahl: | 11 |
Erste Seite: | 3951 |
Letzte Seite: | 3961 |
HeBIS-PPN: | 516507443 |
Institute: | Biochemie, Chemie und Pharmazie |
Angeschlossene und kooperierende Institutionen / MPI für Biophysik | |
DDC-Klassifikation: | 5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie |
Sammlungen: | Universitätspublikationen |
Lizenz (Deutsch): | Creative Commons - CC BY - Namensnennung 4.0 International |