7VC9

Tom20 subunits

Summary for 7VC9

• Entry DOI: 10.2210/pdb7vc9/pdb
• EMDB information: 31889
• Descriptor: Mitochondrial import receptor subunit TOM20 homolog (1 entity in total)
• Functional Keywords: tom20, cryo-em, translocase
• Biological source: Homo sapiens (Human)
• Total number of polymer chains: 2
• Total formula weight: 32639.72

Authors

Liu, D.S.,Sui, S.F. (deposition date: 2021-09-02, release date: 2022-09-07, Last modification date: 2024-09-04)

Primary citation

Su, J.,Liu, D.,Yang, F.,Zuo, M.Q.,Li, C.,Dong, M.Q.,Sun, S.,Sui, S.F.
Structural basis of Tom20 and Tom22 cytosolic domains as the human TOM complex receptors.
Proc.Natl.Acad.Sci.USA, 119:e2200158119-e2200158119, 2022

PubMed Abstract: Mitochondrial preproteins synthesized in cytosol are imported into mitochondria by a multisubunit translocase of the outer membrane (TOM) complex. Functioned as the receptor, the TOM complex components, Tom 20, Tom22, and Tom70, recognize the presequence and further guide the protein translocation. Their deficiency has been linked with neurodegenerative diseases and cardiac pathology. Although several structures of the TOM complex have been reported by cryoelectron microscopy (cryo-EM), how Tom22 and Tom20 function as TOM receptors remains elusive. Here we determined the structure of TOM core complex at 2.53 Å and captured the structure of the TOM complex containing Tom22 and Tom20 cytosolic domains at 3.74 Å. Structural analysis indicates that Tom20 and Tom22 share a similar three-helix bundle structural feature in the cytosolic domain. Further structure-guided biochemical analysis reveals that the Tom22 cytosolic domain is responsible for binding to the presequence, and the helix H1 is critical for this binding. Altogether, our results provide insights into the functional mechanism of the TOM complex recognizing and transferring preproteins across the mitochondrial membrane.

PubMed: 35733257
DOI: 10.1073/pnas.2200158119

Experimental method

ELECTRON MICROSCOPY (13 Å)