From Chaperones to the Membrane with a BAM!

Trends Biochem Sci. 2016 Oct;41(10):872-882. doi: 10.1016/j.tibs.2016.06.005. Epub 2016 Jul 19.

Abstract

Outer membrane proteins (OMPs) play a central role in the integrity of the outer membrane of Gram-negative bacteria. Unfolded OMPs (uOMPs) transit across the periplasm, and subsequent folding and assembly are crucial for biogenesis. Chaperones and the essential β-barrel assembly machinery (BAM) complex facilitate these processes. In vitro studies suggest that some chaperones sequester uOMPs in internal cavities during their periplasmic transit to prevent deleterious aggregation. Upon reaching the outer membrane, the BAM complex acts catalytically to accelerate uOMP folding. Complementary in vivo experiments have revealed the localization and activity of the BAM complex in living cells. Completing an understanding of OMP biogenesis will require a holistic view of the interplay among the individual components discussed here.

Keywords: BAM complex; chaperones; outer membrane proteins.

Publication types

  • Review

MeSH terms

  • Bacterial Outer Membrane Proteins / chemistry*
  • Bacterial Outer Membrane Proteins / genetics
  • Bacterial Outer Membrane Proteins / metabolism
  • Binding Sites
  • Escherichia coli / genetics
  • Escherichia coli / metabolism*
  • Escherichia coli / ultrastructure
  • Escherichia coli Proteins / chemistry*
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism
  • Gene Expression
  • Molecular Chaperones / chemistry*
  • Molecular Chaperones / genetics
  • Molecular Chaperones / metabolism
  • Molecular Dynamics Simulation
  • Periplasm / genetics
  • Periplasm / metabolism*
  • Periplasm / ultrastructure
  • Protein Binding
  • Protein Conformation, beta-Strand
  • Protein Folding
  • Protein Interaction Domains and Motifs
  • Protein Transport
  • Protein Unfolding
  • Thermodynamics

Substances

  • Bacterial Outer Membrane Proteins
  • Escherichia coli Proteins
  • Molecular Chaperones