Architecture and assembly dynamics of the essential mitochondrial chaperone complex TIM9·10·12

Katharina Weinhäupl; Yong Wang; Audrey Hessel; Martha Brennich; Kresten Lindorff-Larsen; Paul Schanda

doi:10.1016/j.str.2021.04.009

Architecture and assembly dynamics of the essential mitochondrial chaperone complex TIM9·10·12

Structure. 2021 Sep 2;29(9):1065-1073.e4. doi: 10.1016/j.str.2021.04.009. Epub 2021 May 10.

Authors

Katharina Weinhäupl¹, Yong Wang², Audrey Hessel¹, Martha Brennich³, Kresten Lindorff-Larsen², Paul Schanda⁴

Affiliations

¹ Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 71, Avenue Des Martyrs, 38044 Grenoble, France.
² Structural Biology and NMR Laboratory, the Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, 2200 Copenhagen, Denmark.
³ European Molecular Biology Laboratory, 38042 Grenoble, France.
⁴ Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 71, Avenue Des Martyrs, 38044 Grenoble, France. Electronic address: paul.schanda@ist.ac.at.

PMID: 33974880
DOI: 10.1016/j.str.2021.04.009

Abstract

Tim chaperones transport membrane proteins to the two mitochondrial membranes. TIM9·10, a 70 kDa protein complex formed by 3 copies of Tim9 and Tim10, guides its clients across the aqueous compartment. The TIM9·10·12 complex is the anchor point at the inner-membrane insertase TIM22. The subunit composition of TIM9·10·12 remains debated. Joint NMR, small-angle X-ray scattering, and MD simulation data allow us to derive a structural model of the TIM9·10·12 assembly, with a 2:3:1 stoichiometry (Tim9:Tim10:Tim12). Both TIM9·10 and TIM9·10·12 hexamers are in a dynamic equilibrium with their constituent subunits, exchanging on a minutes timescale. NMR data establish that the subunits exhibit large conformational dynamics: when the conserved cysteines of the CX₃C-X_n-CX₃C motifs are formed, short α helices are formed, and these are fully stabilized only upon formation of the mature hexameric chaperone. We propose that the continuous subunit exchange allows mitochondria to control their level of inter-membrane space chaperones.

Keywords: NMR spectroscopy; TIM9·10; TIM9·10·12; kinetics; mitochondrial biogenesis; molecular dynamics simulations; protein import; real-time NMR; small-angle X-ray scattering; subunit exchange.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Mitochondrial Precursor Protein Import Complex Proteins / chemistry*
Mitochondrial Precursor Protein Import Complex Proteins / metabolism
Protein Binding
Protein Conformation, alpha-Helical
Protein Multimerization*
Saccharomyces cerevisiae Proteins / chemistry*
Saccharomyces cerevisiae Proteins / metabolism

Substances

Mitochondrial Precursor Protein Import Complex Proteins
Saccharomyces cerevisiae Proteins