Making a beta-barrel: assembly of outer membrane proteins in Gram-negative bacteria

The outer membrane (OM) of Gram-negative bacteria is an essential organelle that serves as a selective permeability barrier by keeping toxic compounds out of the cell while allowing vital nutrients in. How the OM and its constituent lipid and protein components are assembled remains an area of active research. In this review, we describe our current understanding of how outer membrane proteins (OMPs) are delivered to and then assembled in the OM of the model Gram-negative organism Escherichia coli.

► Outer membrane protein (OMP) assembly requires the Bam complex.
► Several structures of the Bam complex members are now available.
► The OMP assembly reaction has been reconstituted in vitro using purified Bam proteins and requires chaperone for full activity.