Beta-barrel outer membrane proteins of Gram-negative bacteria are inserted into the outer membrane by the BAM (beta-barrel assembly machinery) complex. In addition, many Gram-negative bacteria harbour a related complex, called the TAM (translocation and assembly machinery). The role of this second complex is not fully understood, but it is needed for the assembly of some autotransporters and pili. An international team of investigators from the UK, Germany, Norway and Australia, including AROM’s Jack Leo, investigated the requirement of the TAM and some BAM components for the assembly of trimeric autotransporter adhesins, a group of large, adhesive surface proteins that are involved in several diseases. The study shows that of the two complexes, only the essential core components of the BAM – BamA and BamD – are required for outer membrane incorporation and surface exposure of these proteins. Thus, these components might be targeted by novel anti-infective or antimicrobial compounds to prevent binding of bacteria to host cells.
Rooke JL, Icke C, Wells TJ, et al. BamA and BamD are essential for the secretion of trimeric autotransporter adhesins. Front Microbiol. 2020; doi.org/10.3389/fmicb.2021.628879.