Figure 5. Features preventing β-augmentation in D strands of BamB.

Three D-strands of BamB are shown as an orange alpha-carbon trace displaying three features that disfavors β-augmentation: The tryptophan in the docking motifs introduces a bulge in the strand (green) and strategically placed charged residues would have to be buried for extension of the sheets. The N-terminal loop also protects one D strand from b-augmentation.