Fig. 1. Disulfide-locked BamA variants and Fab1 binding impair BAM-mediated OMP folding in vitro.

a BAM-P5L (G393C/G584C) is expected to lock BamA in the lateral-open conformation (PDB code 5LJO⁸), while b BAM-LL (E435C/S665C) is expected to lock BamA in the lateral-closed conformation (PDB code 5D0O⁶). BamA POTRAs 1–4 and BamBCDE are rendered semi-transparent for emphasis on the BamA β-barrel and POTRA-5. The position of the disulfide bond is shown as a yellow bar. Figure made in PyMOL v1.7.2.3. c and d Quantification of folded and unfolded bands from SDS–PAGE band-shift assays (Supplementary Figs. 5 and 6) plotted as fraction folded against time for tOmpA or OmpX, respectively. Data markers represent the average folded fractions calculated from at least two repeats (the number of replicates is shown in Supplementary Table 1) and dashed lines are single exponential fits of the data. Error bars represent range of values covered by the replicates. e and f The initial rates of folding (determined by applying a linear fit to the first 5% of folding data) normalised as a percentage of the mean initial rate obtained for WT BAM, are shown for e tOmpA and f OmpX folding. Bars represent the mean value for each condition, with values for each replicate shown as grey points. Average initial rates, normalised data and ranges are listed in Supplementary Table 1. Folding yields after 24 h are reported in Supplementary Table 2. Figures labelled with “BAM” refer to the full BAM complex (BamABCDE), whilst “BamA” is just BamA alone. Source data for c–f are provided as a source data file.