The TPR domain of BepA is required for productive interaction with substrate proteins and the β-barrel assembly machinery complex.

BepA (formerly YfgC) is an Escherichia coli periplasmic protein consisting of an N-terminal protease domain and a C-terminal tetratricopeptide repeat (TPR) domain. We have previously shown that BepA is a dual functional protein with chaperone-like and proteolytic activities involved in membrane assembly and proteolytic quality control of LptD, a major component of the outer membrane lipopolysaccharide translocon. Intriguingly, BepA can associate with the BAM complex: the β-barrel assembly machinery (BAM) driving integration of β-barrel proteins into the outer membrane.