Abstract
A majority of the proteins targeted to the mitochondria are transported through the translocase of the outer membrane (TOM) complex. Tom70 is a major surface receptor for mitochondrial protein precursors in the TOM complex. To investigate how Tom70 receives the mitochondrial protein precursors, we have determined the crystal structure of yeast Tom70p to 3.0 Å. Tom70p forms a homodimer in the crystal. Each subunit consists primarily of tetratricopeptide repeat (TPR) motifs, which are organized into a right-handed superhelix. The TPR motifs in the N-terminal domain of Tom70p form a peptide-binding groove for the C-terminal EEVD motif of Hsp70, whereas the C-terminal domain of Tom70p contains a large pocket that may be the binding site for mitochondrial precursors. The crystal structure of Tom70p provides insights into the mechanisms of precursor transport across the mitochondrion's outer membrane.
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Acknowledgements
We are grateful to the staff scientists at APS beamline SER-CAT for their help in data collection. This work was supported by grants from the US National Institutes of Health (R01 DK56203 and R01 GM65959) and the US National Aeronautics and Space Administration.
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Y.W. contributed to cloning, protein expression and purification, crystallization and structure determination. B.D.S. contributed to data collection and structure determination.
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Supplementary information
Supplementary Fig. 1
Electron density map for Tom70p from SAD phasing (PDF 300 kb)
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Wu, Y., Sha, B. Crystal structure of yeast mitochondrial outer membrane translocon member Tom70p. Nat Struct Mol Biol 13, 589–593 (2006). https://doi.org/10.1038/nsmb1106
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DOI: https://doi.org/10.1038/nsmb1106
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