TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
*1.C.3.1.1









α-Hemolysin (alpha haemolysin; Hly; Hla; α-toxin). Fragments (13-293 aas) form heptamers like the native full length protein, but a fragment with aas 72-293 formed heptamers, octamers and nonamers. All formed Cl- permeable β-barrel channels (Vécsey-Semjén et al., 2010). The 3-d structure is available (PDB#7AHL). Both symmetry and size of cyclodextrin inhibitors and the toxin pore are important for effective inhibition (Yannakopoulou et al., 2011).  Oxoxylin A inhibits hemolysis by hindering self assembly of the hepatmeric pore (Dong et al. 2013).  Applications of pore-forming α-haemolysin include small- and macromolecule-sensing, targeted cancer therapy, and drug delivery (Gurnev and Nestorovich 2014). Sugawara et al. 2015 studied pore formation. Structural comparisons among monomer, prepore and pore revealed a series of motions in which the N-terminal amino latch released upon oligomerization destroys its own key hydrogen bond betweem Asp45 and Try118. This action initiates the protrusion of the prestem. A Y118F mutant and the N-terminal truncated mutant markedly decreased the hemolytic activity, indicating the importance of the key hydrogen bond and the N-terminal amino latch for pore formation. A dynamic molecular mechanism of pore formation was proposed (Sugawara et al. 2015). Release of ATP from cells may occur directly through transmembrane pores formed by α-toxin (Baaske et al. 2016).

Bacteria
Firmicutes
α-hemolysin of Staphylococcus aureus
*1.C.3.2.1









Hemolysin II

Bacteria
Firmicutes
Hemolysin II of Bacillus cereus
*1.C.3.2.2









β-toxin

Bacteria
Firmicutes
β-toxin of Clostridium perfringens
*1.C.3.2.3









Cytotoxin
Bacteria
Firmicutes
Cytotoxin CytK of Bacillus cereus
*1.C.3.2.4









Necrotic enteritis toxin B precursor, NetB (Keyburn et al., 2008)

Bacteria
Firmicutes
NetB of Clostridium perfringens (A8ULG6)
*1.C.3.2.5









CctA (Clostridium chauvoei toxin A; 317 aas) is the main cytotoxic and haemolytic substance secreted by C. chauvoei.  Vaccination of guinea pigs with CctA in the form of a fusion protein with the E. coli heat labile toxin B subunit (rCctA::LTB) as a peptide adjuvant protected the animals against challenge with spores of virulent C. chauvoei., (Frey et al. 2012).

Bacteria
Firmicutes
Cytotoxin of Clostridium chauvoei

 
*1.C.3.3.1









Leucocidin/Hemolysin family member, LHF
Bacteria
Proteobacteria
LHF member of Vibrio species Ex25, (EDN58324)
*1.C.3.3.2









Leucocidin/Hemolysin toxin family member.  90% identical to a Leukocidin of Vibrio proteolyticus of 305 aas that plays an important role in virulence (Ray et al. 2016).

Bacteria
Proteobacteria
V12G01_16082 of Vibrio alginolyticus (Q1V718)
*1.C.3.4.1









Leucocidin chain F.  3-D structures of the prepore reveal that this is substantially different from the pore structure.  The structures revealed a disordered bottom half of the beta-barrel corresponding to the transmembrane region, and a rigid upper extramembrane half (Yamashita et al. 2014).  Panton-Valentine leukocidin (PVL, encoded by lukSF-PV genes) is a bi-component and pore-forming toxin carried by different staphylococcal bacteriophages (Zhao et al. 2016).

Bacteria
Firmicutes
Leucocidin chain F (LukF) of Staphylococcus aureus (Q53747)
*1.C.3.4.2









Two component β-barrel γ-haemolysin, HlgA·HlgB. Tomita et al. (2011) reported that Hlg2 and LukF form a complex, and that Hlg pores form clusters that release hemoglobin from erythrocytes. The crystal structure of this octameric pore (PDB# 3B07; 2QK7) reveals the beta-barrel pore formation mechanism by the two components (Yamashita et al., 2011).  Dominant-negative mutant toxins may provide novel therapeutics to combat S. aureus infection (Reyes-Robles et al. 2016).  S. aureus beta-barrel pore-forming cytotoxins, including the identification of the toxin receptors on host cells, and their roles in pathogenesis have been reviewed (Reyes-Robles and Torres 2016).

Bacteria
Firmicutes
HlgA·HlgB of Staphylococcus aureus
*1.C.3.4.3









Two component β-barrel γ-haemolysin, HlgC·HlgB. HglC is identical to Leucocidin chain S (LukS) (P31716), and HlgB is identical to the HlgB protein listed under TC# 1.C.3.4.2 (Roblin et al. 2008).

Bacteria
Firmicutes
HlgC·HlgB of Staphylococcus aureus
*1.C.3.4.4









Equid-adapted leukocidin PQ, LukPQ, of 311 (LukP) and 326 aas (LukQ), respectively (Koop et al. 2017).

Bacteria
Firmicutes
LukPQ of Staphylococcus aureus