TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
1.C.57.1.1









Cytotoxin B, TcdB. The minimal pore-forming region is within amino acid residues 830 and 990 including glutamate-970 and glutamate-976. These two residues are essential for pore formation (Genisyuerek et al., 2011).  Other residues important for toxicity have been identified (Zhang et al. 2014).  Residues in the translocation domain of TcdB that form the pore and function in toxin translocation have been identified (Hamza et al. 2016).

Bacteria
Bacillota
Cytotoxin B (TcdB) of Clostridium difficile
1.C.57.1.2









Cytotoxin A
Bacteria
Bacillota
Cytotoxin A of Clostridium difficile
1.C.57.1.3









Lethal toxin
Bacteria
Bacillota
Lethal toxin (cytotoxin L) of Clostridium sordellii
1.C.57.1.4









α-toxin
Bacteria
Bacillota
α-toxin of Clostridium novyi
1.C.57.1.5









Cytotoxin C, TpeL (Amimoto et al., 2007)
Bacteria
Bacillota
TpeL of Clostridium difficile (A2PYQ6)
1.C.57.1.6









MCF toxin of 2993 aas

Bacteria
Pseudomonadota
MCF toxin of Photorhabdus asymbiotica subsp. asymbiotica (Xenorhabdus luminescens)
1.C.57.2.1









Toxin B
Bacteria
Pseudomonadota
Toxin B of E. coli plasmid p0157
1.C.57.2.2









Cytotoxic adherence factor TC0437
Bacteria
Chlamydiota
TC0437 of Chlamydia muridarum
1.C.57.2.3









LifA/Efa1-related large cytotoxin of 3218 aas.

Bacteria
Chlamydiota
LifA of Chlamydia muridarum
1.C.57.3.1









Pasteurella multocida toxin (PMT); dermonecrotic toxin (DMT); mitogenic toxin (ToxA) (Baldwin et al., 2004)
Bacteria
Pseudomonadota
PMT of Pasteurella multocida (P17452)
1.C.57.3.2









Cytotoxic necrotizing factor type 1, Cnf1 (Oswald et al., 1994)
Bacteria
Pseudomonadota
Cnf1 of E. coli (AAN03786)
1.C.57.3.3









Cytotoxic necrotizing factor type 2, Cnf2 (Oswald et al., 1994)
Bacteria
Pseudomonadota
Cnf2 of E. coli (A55260)
1.C.57.3.4









RTX (repeat in toxin) cytotoxin of 5206 aas, also called the "multifunctional-autoprocessing RTX" (MARTXVv) toxin, or Vibrio vulnificus cytotoxin (VVC).  It exists in at least four distinct variants of the rtxA1 gene that encode toxins with different arrangements of effector domains that arose by recombination.  VVC, in addition to being a pore-forming toxin, may be a transmembrane toxin with the ability to induce apoptosis in human vascular endothelial cells and tumor cells (Zhao et al. 2009). The protein has an α,β-hydrolase domain (residues ~2900 - 3120).

Bacteria
Pseudomonadota
RTX cytotoxin of Vibrio vulnificus (BAC97056)
1.C.57.3.5









Multifunctional-autoprocessing repeats-in-toxin, RtxA or Rtx, of 4558 aas. It is the precursor of a multifunctional toxin that causes destruction of the actin cytoskeleton by covalent cross-linking of actin and inactivation of Rho GTPases when translocated into the host cytoplasm (Satchell 2015). Upon translocation into the host cell, it undergoes autoprocessing in cis mediated by the peptidase C80 domain (also named CPD domain). The protease activity is activated upon binding inositol hexakisphosphate (InsP6), present at the host cell membrane, delivering the cysteine protease domain-containing toxin F3 chain to the host cytosol (Sheahan et al. 2007, Shen et al. 2009). It forms a pore in the plasma membrane of a eukaryotic cell to deliver the toxin (Woida and Satchell 2018).

Bacteria
Pseudomonadota
RtxA of Vibrio cholerae
1.C.57.4.1









Putative toxin A of 294 aas

Bacteria
Spirochaetota
Toxin A of Brachyspira intermedia