Polypeptides traverse the mitochondrial envelope in an extended state

FEBS Letters

Pfanner, Nikolaus²  Hartl, Franz-Ulrich²  Rassow, Joachim²  Neupert, Walter²  Guiard, Bernard¹ 

[1] Centre de Génétique Moléculaire, Laboratoire propre du CNRS associé á l'Université Pierre et Marie Curie, 91190 Gif-sur-Yvette, France;Institut für Physiologische Chemie, Universität München, Goethestrasse 33, W-8000 München 2, FRG

关键词: Mitochondria;    Contact site;    Protein translocation;    Protein unfolding;    DHFR;    dihydrofolate reductase;    BSA;    bovine serum albumin;    b 2(1-x)+y -DHFR;    hybrid protein between x amino-terminal amino acids residues of the precursor of cytochrome b 2 and entire DHFR connected by y linker amino acids;    p-;    i-;    m-;    precursor-;    intermediate;    and mature-sized forms of a protein;    respectively;    Mops;    3-(N-morpholino)propanesulfonic acid;    MTX;    methotrexate backbone of the polypeptide chain becomes exposed while being translocated through proteinaceous sites in mitochondrial contact zones;   

DOI  :  10.1016/0014-5793(90)81469-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Most mitochondrial proteins are synthesized as precursors in the cytosol and imported through the contact sites between outer and inner mitochondrial membranes. The molecular mechanism of membrane translocation of precursor proteins is largely unclear. For this report, various hybrid proteins between portions of the precursor of cytochrome b ₂ and the entire dihydrofolate reductase (DHFR) were accumulated in mitochondrial contact sites. We unexpectedly found that about 30 amino acid residues of the polypeptide chain in transit were sufficient to span both membranes. This suggests linear translocation of the polypeptide chain and presents evidence for a high degree of unfolding of polypeptides traversing the mitochondrial membranes.

【 授权许可】

Unknown