TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
3.A.15.1.1









The pullulanase secretion system
Bacteria
Pseudomonadota
PulC-O and PulS of Klebsiella pneumoniae
3.A.15.2.1









The pilin secretion/fimbrial assembly system. The PilB and PilT ATPases act antagonistically in Type IV pilus function in Myxococcus xanthus. ATP binding and hydrolysis by PilT are essential for T4P extension while ATP binding and hydrolysis by PilB are essential for T4P retraction. Thus, PilB and PilT act at distinct steps in the T4P extension/retraction cycle (Jakovljevic et al., 2008).
Bacteria
Pseudomonadota
PilABCDEQTU-FimTU of Pseudomonas aeruginosa
3.A.15.2.2









α-helical pore-forming toxin-coregulated pilus biosynthesis protein E, TcpE, of 340aas and 3TMSs with an internal repeat (Kolappan and Craig 2013).

Bacteria
Pseudomonadota
TcpE of Vibrio cholerae (P0C6C9)
3.A.15.3.1









The Legionella secretion pathway (Lsp)/fimbrial assembly system, LspC-M (required for survival and replication in the host cell; Hales and Shuman, 1999; Rossier et al., 2004; De Buck et al., 2007)

Bacteria
Pseudomonadota
The LspC-M system of Legionella pneumophila:
Prepilin peptidase, PilD (287aas; O68433)
Type IV pseudopilin, LspF (126aas; Q9XD72)
Type IV pseudopilin, LspG (140aas; Q9XD71)
Type IV pseudopilin, LspH (161aas; Q9XD70)
Type IV pseudopilin, LspI (125aas; Q9XD69)
Type IV pseudopilin, LspJ (205aas; Q9XD68)
Type IV pseudopilin, LspK (322aas; Q9XD67)
Outer membrane secretin, LspD (730aas; Q9AGM8)
ATPase, LspE (494aas;Q9AGM7)
Conserved IISP protein, LspC (169aas; Q5ZX38)
Conserved IISP protein, LspL (379aas; Q5ZUD0)
Conserved IISP protein, LspM (156aas; Q5ZUC9)
3.A.15.4.1









The Leptospiral type II protein secretion system (Gsp)/fimbrial assembly system, PilD/GspCDEFGHIJKLM (Buyuktimkin and Saier 2015).

Bacteria
Spirochaetota
PilD/GspCDEFGHIJKLM of Leptospira interrogans
3.A.15.4.2









The tri-component complex including (1) EbsA of 125 aas, homologs of which are highly conserved and widespread in diverse cyanobacteria but are not found outside this clade; (2) PilB, a 666 aa type IV fimbrial biogenesis protein, and (3) Hfq, a 70 aa host factor-1 protein. The tripartite complex of EbsA, Hfq, and the ATPase homolog PilB (formerly called T2SE) are all three required for the assembly of the hairlike type IV pili (T4P) appendages, for DNA competence, and for exoproteome formation in addition to its role in biofilm self-suppression (Yegorov et al. 2021).

Bacteria
Cyanobacteriota
EbrA of 125 aas
PilB of 666 aas
Hfq of 70 aas