Open AccessThe sacrificial adaptor protein Skp functions to remove stalled substrates from the β-barrel assembly machine
Author(s) -
Ashton N. Combs,
Thomas J. Silhavy
Publication year - 2021
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.2114997119
Subject(s) - periplasmic space , protein folding , chaperone (clinical) , bacterial outer membrane , biogenesis , dsba , microbiology and biotechnology , biology , foldase , biophysics , biochemistry , chemistry , groel , escherichia coli , medicine , pathology , gene
Significance The outer membrane (OM) of gram-negative bacteria acts as a robust permeability barrier to enable cell survival in a wide variety of harsh environments. Crucial to OM integrity are β-barrel outer membrane proteins (OMPs) that are assembled into the membrane by the broadly conserved β-barrel assembly machine (Bam) complex. Here, we identify specific roles for the periplasmic chaperone Skp in functioning as a sacrificial adaptor protein to remove stalled substrates from the Bam complex, imposing an active quality control mechanism that ensures efficient assembly of nascent OMPs into the OM. This work identifies the molecular mechanism of the Skp/DegP functional relationship and clarifies the long-standing paradox of how substrate release from the high-affinity, long-lived Skp–OMP complex is achieved in vivo.