title: Molecular basis of the dynamic structure of the TIM23 complex in the mitochondrial intermembrane space.
abstract: The presequence translocase TIM23 is a highly dynamic complex in which its subunits can adopt multiple conformations and undergo association-dissociation to facilitate import of proteins into mitochondria. Despite the importance of protein-protein interactions in TIM23, little is known about the molecular details of these processes. Using nuclear magnetic resonance spectroscopy, we characterized the dynamic interaction network of the intermembrane space domains of Tim23, Tim21, Tim50, and Tom22 at single-residue level. We show that Tim23(IMS) contains multiple sites to efficiently interact with the intermembrane space domain of Tim21 and to bind to Tim21, Tim50, and Tom22. In addition, we reveal the atomic details of the dynamic Tim23(IMS)-Tim21(IMS) complex. The combined data support a central role of the intermembrane space domain of Tim23 in the formation and regulation of the presequence translocase.
authors.affiliation: Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.
authors.forename: Rakhi
authors.initials: R
authors.lastname: Bajaj
authors.affiliation: Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany; German Center for Neurodegenerative Diseases (DZNE), 37077 Göttingen, Germany.
authors.forename: Łukasz
authors.initials: Ł
authors.lastname: Jaremko
authors.affiliation: Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.
authors.forename: Mariusz
authors.initials: M
authors.lastname: Jaremko
authors.affiliation: Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Becker
authors.affiliation: Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany; German Center for Neurodegenerative Diseases (DZNE), 37077 Göttingen, Germany; Center for the Molecular Physiology of the Brain, University Medicine Göttingen, 37073 Göttingen, Germany. Electronic address: markus.zweckstetter@dzne.de.
authors.forename: Markus
authors.initials: M
authors.lastname: Zweckstetter
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D017124:Conserved Sequence; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins / Q000737:chemistry / Q000378:metabolism; D051336:Mitochondrial Membranes / Q000378:metabolism; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D008958:Models, Molecular; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D026901:Membrane Transport Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D046912:Multiprotein Complexes; D029701:Saccharomyces cerevisiae Proteins; C083081:TIM23 protein, S cerevisiae; C469615:TIM50 protein, S cerevisiae; C090857:TOM22 protein, S cerevisiae; C500397:Tim21 protein, S cerevisiae