PROSITE documentation PDOC00436
Thiol-activated cytolysins signature


Thiol-activated cytolysins [1,2] are toxins produced by a variety of Gram-positive bacteria and are characterized by their ability to lyse cholesterol-containing membranes, their reversible inactivation by oxidation and their capacity to bind to cholesterol. The sequences of some of these toxins is currently known:

  • Alveolysin (gene alv) from Bacillus alvei.
  • Ivanolysin (gene ilo) from Listeria ivanovii.
  • Listeriolysin O (gene hlyA) from Listeria monocytogenes.
  • Perfringolysin O (theta-toxin) (gene pfo) from Clostridium perfringens.
  • Pneumolysin (gene ply) from Streptococcus pneumoniae.
  • Seeligeriolysin (gene lso) from Listeria seeligeri.
  • Streptolysin O (gene slo) from Streptococcus pyogenes.

All these proteins contain a single cysteine residue, located in their C-terminal section, which has been shown [3] to be essential for the binding to cholesterol. This cysteine is located in a highly conserved region that can be used as a signature pattern.

Last update:

October 1993 / Pattern and text revised.


Technical section

PROSITE method (with tools and information) covered by this documentation:

THIOL_CYTOLYSINS, PS00481; Thiol-activated cytolysins signature  (PATTERN)


1AuthorsAlouf J.E. Geoffroy C.
Source(In) Bacterial proteins toxins, pp 165-171, Alouf J.E., Ferenbach F.J., Free J.H., Jeljaszewicz J., Ed., Academic Press, London, (1984).

2AuthorsGeoffroy C. Mengaud J. Alouf J.E. Cossart P.
SourceJ. Bacteriol. 172:7301-7305(1990).

3AuthorsIwamoto M. Ohno-Iwashita Y. Ando S.
TitleRole of the essential thiol group in the thiol-activated cytolysin from Clostridium perfringens.
SourceEur. J. Biochem. 167:425-430(1987).
PubMed ID2888650

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