biostudies-literatureWebb CTIntramural NIH HHSNHMRC Postgraduate Research ScholarshipIntramural Research Program of the National Institutes of Health, National Institute of Diabetes and Digestive and Kidney DiseasesNational Health and Medical Research Council (NHMRC) of Australia545-55https://www.ebi.ac.uk/biostudies/studies/S-EPMC3433275biostudies-literatureUnknown422(4)The β-barrel assembly machinery (BAM) complex drives the assembly of β-barrel proteins into the outer membrane of gram-negative bacteria. It is composed of five subunits: BamA, BamB, BamC, BamD, and BamE. We find that the BAM complex isolated from the outer membrane of Escherichia coli consists of a core complex of BamA:B:C:D:E and, in addition, a BamA:B module and a BamC:D module. In the absence of BamC, these modules are destabilized, resulting in increased protease susceptibility of BamD and BamB. While the N-terminus of BamC carries a highly conserved region crucial for stable interaction with BamD, immunofluorescence, immunoprecipitation, and protease-sensitivity assays show that the C-terminal domain of BamC, composed of two helix-grip motifs, is exposed on the surface of E. coli. ThJournal of molecular biologyDynamic association of BAM complex modules includes surface exposure of the lipoprotein BamC.PMC3433275606788ZIA DK036139-05Buchanan SKLithgow TWebb CTNoinaj NSelkrig JPerry AJfalseDynamic association of BAM complex modules includes surface exposure of the lipoprotein BamC.The β-barrel assembly machinery (BAM) complex drives the assembly of β-barrel proteins into the outer membrane of gram-negative bacteria. It is composed of five subunits: BamA, BamB, BamC, BamD, and BamE. We find that the BAM complex isolated from the outer membrane of Escherichia coli consists of a core complex of BamA:B:C:D:E and, in addition, a BamA:B module and a BamC:D module. In the absence of BamC, these modules are destabilized, resulting in increased protease susceptibility of BamD and BamB. While the N-terminus of BamC carries a highly conserved region crucial for stable interaction with BamD, immunofluorescence, immunoprecipitation, and protease-sensitivity assays show that the C-terminal domain of BamC, composed of two helix-grip motifs, is exposed on the surface of E. coli. Th2012-01-01T00:00:00Z2012 Sep2025-04-18T16:58:39.066Z2019-03-27T00:57:26ZS-EPMC34332752268335510.1016/j.jmb.2012.05.035