6ucv
From Proteopedia
Cryo-EM structure of the mitochondrial TOM complex from yeast (tetramer)
Structural highlights
Function[TOM6_YEAST] Component of the TOM (translocase of outer membrane) receptor complex responsible for the recognition and translocation of cytosolically synthesized mitochondrial preproteins. TOM6 is involved in assembly and stability of the TOM complex.[1] [TOM40_YEAST] Channel-forming protein essential for import of protein precursors into mitochondria.[2] [TOM5_YEAST] Component of the TOM (translocase of outer membrane) receptor complex responsible for the recognition and translocation of cytosolically synthesized mitochondrial preproteins. TOM5 is involved in insertion of preproteins into the TOM40 translocation pore.[3] [TOM22_YEAST] Central component of the TOM (translocase of outer membrane) receptor complex responsible for the recognition and translocation of cytosolically synthesized mitochondrial preproteins. Together with TOM20 and TOM70 functions as the transit peptide receptor at the surface of the mitochondrion outer membrane and facilitates the movement of preproteins into the TOM40 translocation pore. Docks TOM20 and TOM70 for interaction with the general TOM40 import pore (GIP) complex. May regulate the TOM machinery organization, stability and channel gating.[4] [5] [6] [TOM7_YEAST] Component of the TOM (translocase of outer membrane) receptor complex responsible for the recognition and translocation of cytosolically synthesized mitochondrial preproteins. TOM7 is involved in assembly and stability of the TOM complex.[7] Publication Abstract from PubMedNearly all mitochondrial proteins are encoded by the nuclear genome and imported into mitochondria after synthesis on cytosolic ribosomes. These precursor proteins are translocated into mitochondria by the TOM complex, a protein-conducting channel in the mitochondrial outer membrane. We have determined high-resolution cryo-EM structures of the core TOM complex from Saccharomyces cerevisiae in dimeric and tetrameric forms. Dimeric TOM consists of two copies each of five proteins arranged in two-fold symmetry: pore-forming beta-barrel protein Tom40 and four auxiliary alpha-helical transmembrane proteins. The pore of each Tom40 has an overall negatively charged inner surface attributed to multiple functionally important acidic patches. The tetrameric complex is essentially a dimer of dimeric TOM, which may be capable of forming higher-order oligomers. Our study reveals the detailed molecular organization of the TOM complex and provides new insights about the mechanism of protein translocation into mitochondria. Cryo-EM structure of the mitochondrial protein-import channel TOM complex at near-atomic resolution.,Tucker K, Park E Nat Struct Mol Biol. 2019 Nov 18. pii: 10.1038/s41594-019-0339-2. doi:, 10.1038/s41594-019-0339-2. PMID:31740857[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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