TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
1.B.48.1.1









The 36 β-stranded outer membrane porin, CsgG with auxiliary subunits, CsgE and CsgF (Goyal et al. 2014). Curli are functional amyloid fibres that constitute the major protein component of the extracellular matrix in pellicle biofilms formed by Bacteroidetes and Proteobacteria (predominantly of the α and γ classes). They provide a fitness advantage in pathogenic strains and induce a strong pro-inflammatory response during bacteraemia. Curli formation requires a dedicated protein secretion machinery comprising the outer membrane lipoprotein CsgG and two soluble accessory proteins, CsgE and CsgF. Curli formation requires a dedicated protein secretion machinery comprising the outer membrane lipoprotein CsgG and two soluble accessory proteins, CsgE and CsgF. Goyal et al. 2014 reported the X-ray structure of Escherichia coli CsgG in a non-lipidated, soluble form as well as in its native membrane-extracted conformation. CsgG forms an oligomeric transport complex composed of nine anticodon-binding-domain-like units that give rise to a 36-stranded β-barrel that traverses the bilayer and is connected to a cage-like vestibule in the periplasm. The transmembrane and periplasmic domains are separated by a 0.9-nm channel constriction composed of three stacked concentric phenylalanine, asparagine and tyrosine rings that may guide the extended polypeptide substrate through the secretion pore. The specificity factor CsgE forms a nonameric adaptor that binds and closes off the periplasmic face of the secretion channel, creating a 24,000 Å pre-constriction chamber. The structural, functional and electrophysiological analyses imply that CsgG is an ungated, non-selective protein secretion channel that is expected to employ a diffusion-based, entropy-driven transport mechanism (Goyal et al. 2014). SuFEx chemistry for cross-linking enables covalent assembly of a 280-kDa 18-subunit pore-forming complex used for DNA sequencing (Schnaider et al. 2024).

Bacteria
Pseudomonadota
CsgEFG of E. coli
1.B.48.1.2









Curli assembly/transport compenent, CsgG. (TolB-N Superfamily of CDD)

Bacteria
Chlorobiota
CsgG of Chlorobium phaeobacteroides
1.B.48.1.3









CsgG homologue

Bacteria
Cyanobacteriota
CsgG homologue of Synechococcus sp. JA-2-3B'a(2-13)
1.B.48.1.4









CsgG homologue

Bacteria
Deinococcota
CsgG homologue of Thermus thermophilus
   

1.B.48.1.5









CsgG homologue of 272 aas

Bacteria
Pseudomonadota
CsgG homologue of Glaciecola nitratireducens
1.B.48.1.6









CsgG homologue of 347 aas

Bacteria
Bacillota
CsgG homologue of Halobacteroides halobius
1.B.48.1.7









Putative lipoprotein of 187 aas

Bacteria
Spirochaetota
Putative lipoprotein of Leptospira interrogans
1.B.48.1.8









Uncharacterized protein of 303 aas

Bacteria
Thermodesulfobacteriota
UP of Desulfarculus baarsii
1.B.48.1.9









CsgG homologue of 485 aas

Bacteria
Spirochaetota
CsgG homologue of Leptospira interrogans
1.B.48.1.10









Uncharacterized protein of 248 aas

Bacteria
Spirochaetota
UP of Leptospira biflexa
1.B.48.1.11









Putative porin of 333 aas and 1 N-terminal TMS

Bacteria
Bdellovibrionota
PP of Bdellovibrio exovorus
1.B.48.2.1









Putative porin of 394 aas

Bacteria
Thermotogota
Porin of Thermosipho melanesiensis
1.B.48.2.2









Putative curli porin, CgsG of 489 aas

Bacteria
Spirochaetota
CgsG of Brachyspira pilosicoli
1.B.48.2.3









CsgG homologue of 412 aas

Bacteria
Thermotogota
CsgG homologue of Marinitoga piezophila
1.B.48.2.4









CsgG homologue of 399 aas

Bacteria
Aquificota
CsgG homologue of Persephonella marina
1.B.48.2.5









Uncharacterized protein of 275 aas

Bacteria
Bacteroidota
UP of Bacteroides xylanisolvens
1.B.48.2.6









Uncharacterized protein of 588 aas

Bacteria
Thermotogota
UP of Thermosipho melanesiensis
1.B.48.3.1









Protein with N-terminal CsgG domain and two central PEGA domains (similar to beta-barrel S-layer domains of 464 aas.

Bacteria
Spirochaetota
CsgG/PEGA protein of Spirochaeta thermophila
1.B.48.3.2









Protein with N-terminal CsgG domain, central PEGA domain and C-terminal autotransporter domain of 422 aas.  The PEGA domain (residues 160 - 220) is found in the OMR Ferripyochelin receptor, FptA (1.B.14.1.8), repeated at least 3 times every ~36 aas.

Bacteria
Spirochaetota
Uncharacterized protein of Turneriella parva (Leptospira parva)
1.B.48.3.3









Putative adenylate cyclase of 478 aas with N-terminal CsgG domain.

Bacteria
Myxococcota
Uncharacterized protein of Myxococcus stipitatus
1.B.48.3.4









S-layer-like β-barrel domain protein of 527aas and 2 N- and C-terminal TMSs.

Bacteria
Spirochaetota
S-layer-like protein of Leptospira interrogans (Q8F8C2)
1.B.48.4.1









CsgG homologue of 397 aas

Bacteria
Aquificota
CsgG homologue of Thermovibrio ammonificans
1.B.48.4.2









Uncharacterized protein of 430 aas

Bacteria
Pseudomonadota
UP of Alcanivorax borkumensis
1.B.48.5.1









Uncharacterized protein, YcfM of 196 aas

Bacteria
Pseudomonadota
YcfM of Vibrio parahaemolyticus
1.B.48.6.1









Uncharacterized protein of 448 aas

Bacteria
Spirochaetota
UP of Treponema denticola