3FP4

Crystal structure of Tom71 complexed with Ssa1 C-terminal fragment

Summary for 3FP4

• Entry DOI: 10.2210/pdb3fp4/pdb
• Related: 3FP1 3FP2 3FP3
• Descriptor: TPR repeat-containing protein YHR117W, Ssa1, CHLORIDE ION, ... (6 entities in total)
• Functional Keywords: tom71, hsp70, mitochondria, translocation, chaperone, phosphoprotein, tpr repeat, transport protein
• Biological source: Saccharomyces cerevisiae (yeast); More
• Cellular location: Mitochondrion outer membrane; Single-pass membrane protein: P38825
• Total number of polymer chains: 2
• Total formula weight: 62520.60

Authors

Li, J.,Qian, X.,Hu, J.,Sha, B. (deposition date: 2009-01-03, release date: 2009-07-28, Last modification date: 2023-09-06)

Primary citation

Li, J.,Qian, X.,Hu, J.,Sha, B.
Molecular chaperone Hsp70/Hsp90 prepares the mitochondrial outer membrane translocon receptor Tom71 for preprotein loading.
J.Biol.Chem., 284:23852-23859, 2009

PubMed Abstract: The preproteins targeted to the mitochondria are transported through the translocase of the outer membrane complex. Tom70/Tom71 is a major surface receptor of the translocase of the outer membrane complex for mitochondrial preproteins. The preproteins are escorted to Tom70/Tom71 by molecular chaperones Hsp70 and Hsp90. Here we present the high resolution crystal structures of Tom71 and the protein complexes between Tom71 and the Hsp70/Hsp90 C terminus. The crystal structures indicate that Tom70/Tom71 may exhibit two distinct states. In the closed state, the N-terminal domain of Tom70/Tom71 partially blocks the preprotein-binding pocket. In the open state, the N-terminal domain moves away, and the preprotein-binding pocket is fully exposed. The complex formation between the C-terminal EEVD motif of Hsp70/Hsp90 and Tom71 could lock Tom71 in the open state where the preprotein-binding pocket of Tom71 is ready to receive preproteins. The interactions between Hsp70/Hsp90 and Tom71 N-terminal domain generate conformational changes that may increase the volume of the preprotein-binding pocket. The complex formation of Hsp70/Hsp90 and Tom71 also generates significant domain rearrangement within Tom71, which may position the preprotein-binding pocket closer to Hsp70/Hsp90 to facilitate the preprotein transfer from the molecular chaperone to Tom71. Therefore, molecular chaperone Hsp70/Hsp90 may function to prepare the mitochondrial outer membrane receptor Tom71 for preprotein loading.

PubMed: 19581297
DOI: 10.1074/jbc.M109.023986

Experimental method

X-RAY DIFFRACTION (2.14 Å)