The dynamic lateral gate of the mitochondrial β-barrel biogenesis machinery is blocked by darobactin A.

ABSTRACT: 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 i

SUBMITTER: Diederichs KA 

PROVIDER: S-EPMC12728192 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature