TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
*1.B.20.1.1









Outer membrane toxin channel protein, ShlB
Bacteria
Proteobacteria
ShlB of Serratia marcescens
*1.B.20.1.2









Outer membrane hemolysin secretion protein, HpmA
Bacteria
Proteobacteria
HpmA of Proteus mirabilis
*1.B.20.1.3









Outer membrane transporter essential for contact-dependent growth inhibition, CdiB; exports CdiA (AAZ57198) (Aoki et al., 2005).  Mediates contact-dependent growth inhibition (CDI), a phenomenon by which bacterial cell growth is regulated by direct cell-to-cell contact. The CdiA/CdiB two-partner secretion system appears to play a direct role (Aoki et al. 2008).

Bacteria
Proteobacteria
CdiB of E. coli (AAZ57197)
*1.B.20.1.4









The outer membrane haemolysin-like OptA exporter, OptB (OptA, AAG55657, resembles Alveicin B, 1.C.75.1.1) (Choi et al., 2007). Choi and Bernstein (2010) have demonstrated that BpaA is secreted in a two step process, and the C-terminus of OtpA enters the OtpB pore before the N-terminus.

Bacteria
Proteobacteria
OptB of E. coli (Q8XAN8)
*1.B.20.1.5









The HrpA/HrpB TPS adhesin system (HrpB = HecB) (Schmitt et al., 2007)

Bacteria
Proteobacteria
HecB of Neisseria meningitidis (Q9JY22)
*1.B.20.1.6









Outer membrane hemagglutinin secretion protein, FhaC. Functionally important conserved motifs have been identified (Delattre et al., 2010).  The x-ray structure reveals a beta-barrel pore obstructed by two structural elements conserved in all two partner secretion systems, an N-terminal α-helix and an extracellular loop.  FhaC goes from the closed to the open state in the presence of the filamentous haemagglutinin adhesin, FHA.  The N-terminal α-helix is displaced into the periplasm during FHA secretion (Guérin et al. 2014).  With two POTRA domains in the periplasm, a transmembrane beta barrel and a large loop harboring a functionally important motif, FhaC epitomizes the conserved features of the superfamily (Jacob-Dubuisson et al. 2009). The conserved secretion domain of FHA interacts with the POTRA domains, specific extracellular loops and strands of FhaC and the inner beta-barrel surface. The interaction map indicates a funnel-like pathway, with conformationally flexible FHA entering the channel in a non-exclusive manner and exiting along a four-stranded beta-sheet at the surface of the FhaC barrel. This sheet of FhaC guides the secretion domain of FHA along discrete steps of translocation and folding (Baud et al. 2014).  The membrane-proximal POTRA domain exists in several conformations, and the binding of FHA displaces this equilibrium (Guérin et al. 2015).

Bacteria
Proteobacteria
FhaC of Bordetella pertussis (P35077)
*1.B.20.1.7









Portra domain containing ShlB-type family protein of 354 aas

Bacteria
Proteobacteria
ShlB-type protein of E. coli
*1.B.20.1.8









Hemolysin activator protein, ExlB of 570 aas. Exports the exotoxin, ExlA (TC# 1.C.73.1.1) (Elsen et al. 2014; Basso et al. 2017).

Bacteria
Proteobacteria
ExlB of Pseudomonas aeruginosa
*1.B.20.1.9









Outer membrane exporter of the ChlA exotoxin, ChlB, of 566 aas (Brumbach et al. 2007).

Bacteria
Proteobacteria
ChlB of Chromobacterium violaceum
*1.B.20.2.1









Hypothetical protein of 579 aas

Bacteria
Proteobacteria
HP of Erythrobacter litoralis
*1.B.20.3.1









Heme-hemopexin utilization protein B precursor
Bacteria
Proteobacteria
Hxb2 of Haemophilus influenzae
*1.B.20.3.2









HMW1B outer membrane exporter, required for secretion of HMW1A and HMW2A adhesins (exhibit a twin pore dimeric structure) (Li et al., 2007) and forms a large-conductance channel (Duret et al., 2008).  The protein has a modular three domain structure: an N-terminal  membrane domain, a central periplasmic domain and a C-terminal membrane anchor domain that oligomerizes and forms a pore (Surana et al. 2006).  The periplasmic domain is required for secretion.

Bacteria
Proteobacteria
HMW1B of Haemophilus influenzae (Q4QJR3)
*1.B.20.3.3









EtpB, a functionally asymmetric pore with three conductance states (Meli et al., 2009).

Bacteria
Proteobacteria
EtpB of E. coli (Q29XT8)
*1.B.20.3.4









The BpaB outer membrane channel protein. Exports BpaA (Brown et al., 2004). BpaA is very large (~530kDa) and contains 3 repeats, each ~700aas in length.

Bacteria
Proteobacteria
BpaB of Burkholderia pseudomallei (Q6Y659)
*1.B.20.3.5









Hypothetical protein of 576 aas

Bacteria
Bacteroidetes/Chlorobi group
HP of Chlorobium chlorochromatii
*1.B.20.3.6









Two component virulence-related protein exporter, PdtB of 544 aas.  Exports the PdtA adhesin (4180 aas; Q9I5N6) to the cell surface for processing (Faure et al. 2014).

Bacteria
Proteobacteria
PdtB of Pseudomonas aeruginosa