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Science. 2018 Jan 19;359(6373). pii: eaah6834. doi: 10.1126/science.aah6834.

Membrane protein insertion through a mitochondrial β-barrel gate.

Author information

1
Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research (ZBMZ), Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany.
2
Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany.
3
Centre de Génétique Moléculaire, CNRS, 91190 Gif-sur-Yvette, France.
4
BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.

Abstract

The biogenesis of mitochondria, chloroplasts, and Gram-negative bacteria requires the insertion of β-barrel proteins into the outer membranes. Homologous Omp85 proteins are essential for membrane insertion of β-barrel precursors. It is unknown if precursors are threaded through the Omp85-channel interior and exit laterally or if they are translocated into the membrane at the Omp85-lipid interface. We have mapped the interaction of a precursor in transit with the mitochondrial Omp85-channel Sam50 in the native membrane environment. The precursor is translocated into the channel interior, interacts with an internal loop, and inserts into the lateral gate by β-signal exchange. Transport through the Omp85-channel interior followed by release through the lateral gate into the lipid phase may represent a basic mechanism for membrane insertion of β-barrel proteins.

PMID:
29348211
PMCID:
PMC5959003
DOI:
10.1126/science.aah6834
[Indexed for MEDLINE]
Free PMC Article

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