%0 Journal Article
%A Diederichs, Kathryn A.
%A Botos, Istvan
%A Hayashi, Scout
%A Gutishvili, Gvantsa
%A Kotov, Vadim
%A Kuo, Katie
%A Iinishi, Akira
%A Cooper, Gwendolyn
%A Schwarz, Benjamin
%A Celia, Herve
%A Marlovits, Thomas
%A Lewis, Kim
%A Gumbart, James C.
%A Mindell, Joseph A.
%A Buchanan, Susan K.
%T The dynamic lateral gate of the mitochondrial β-barrel biogenesis machinery is blocked by darobactin A
%J Nature Communications
%V 16
%N 1
%@ 2041-1723
%C [London]
%I Springer Nature
%M PUBDB-2025-05268
%P 11349
%D 2025
%X The folding and insertion of β-barrel proteins into the mitochondrial outer membrane is facilitated by the sorting and assembly machinery (SAM) complex. Here we report two 2.8 Å cryo-EM structures of the Thermothelomyces thermophilus SAM complex in the absence of substrate in which the Sam50 lateral gate adopts two different conformations: the first is a closed lateral gate as observed in previously published structures, while the second contains a Sam50 with the first four β-strands rotated outwards by approximately 45°, resulting in an open lateral gate. The observed monomeric open conformation contrasts our previous work where the open conformation was adopted by non-physiological up-down dimers. To understand how these lateral gate dynamics are influenced by substrate, we studied the interaction of the SAM complex with a β-signal peptide mimic, darobactin A. Darobactin A binds to the SAM complex with nanomolar affinity and inhibits the import and assembly of mitochondrial β-barrel proteins in vitro. Lastly, we solved a 3.0 Å cryo-EM structure of the Thermothelomyces thermophilus SAM complex bound to darobactin A, which reveals that darobactin A stabilizes the Sam50 lateral gate similar to the open conformation by binding to strand β1, therefore blocking β-barrel biogenesis.
%F PUB:(DE-HGF)16
%9 Journal Article
%R 10.1038/s41467-025-66417-0
%U https://bib-pubdb1.desy.de/record/641981