Dissemin is shutting down on January 1st, 2025

Published in

Elsevier, Journal of Biological Chemistry, 39(277), p. 36100-36108, 2002

DOI: 10.1074/jbc.m202310200

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Assembly of Tim9 and Tim10 into a functional chaperone.

This paper is made freely available by the publisher.
This paper is made freely available by the publisher.

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Postprint: archiving allowed
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Data provided by SHERPA/RoMEO

Abstract

The TIM10 complex is localized in the mitochondrial intermembrane space and mediates insertion of hydrophobic proteins at the inner membrane. We have characterized TIM10 assembly and analyzed the structural properties of its subunits, Tim9 and Tim10. Both proteins are alpha-helical with a protease-resistant central domain, and each self-associates to form mainly dimers and trimers in solution. Tim9 and Tim10 bound to one another with submicromolar affinity in equimolar amounts and assembled in a stable, significantly extended complex that was indistinguishable from the native mitochondrial TIM10 complex. Importantly, the reconstituted TIM10 complex is functional because it bound to the physiological substrate ADP/ATP carrier and displayed chaperone activity in refolding the model substrate firefly luciferase. These data demonstrate that the individual subunits can exist as independent, dynamically self-associating proteins. Assembly into the thermodynamically stable hexameric complex is necessary for the TIM10 chaperone function.