Table 3. Regions of BpaB with high level of sequence similarity to conserved domains in the NCBI Entrez Conserved Domain Database (CDD).

BpaB residues	E-value	CDD domain	CDD number	Description
1–24	8.25e-08	ESPR	257462	Extended Signal Peptide of Type V secretion system. Present at the N-terminus of the signal peptides of proteins belonging to the Type V secretion systems, including AT.
108–251	2.16e-3	LbR-like Superfamily	248061	Left-handed β-roll. This family contains a variety of domains with a left-handed β-roll structure including virulence factors and various other proteins such as the oligomeric AT UspA1 of Moraxella catarrhalis and YadA of Yersinia enterocolitica.
346–439	1.93e-12	LbR_YadA-like	240612	YadA-like, left-handed β-roll. This group contains the collagen-binding domain of the virulence factor and oligomeric AT YadA of Y. enterocolitica.
330–1090	1.9e-16	HIA	227614	Autotransporter adhesin [Intracellular trafficking and secretion/ Extracellular structures] first identified in the oligomeric AT Hia of Haemophilus influenzae.
1014–1090	9.64e-14	YadA_anchor	252233	YadA-like C-terminal region. Represents the C-terminal 120 aa of several oligomeric AT including Y. enterocolitica YadA, M. catarrhalis UspA2, Haemophilus ducreyi DsrA and E. coli Eib. The C-terminal 9 aa, consisting of alternating hydrophobic aa ending in F or W, comprise a targeting motif for the OM of the Gram-negative cell envelope. This region is also important for oligomerization.