1.C.60 The Two-component Enterococcus faecalis Cytolysin (EFC) Family

The EFC family includes a single member, the cytolysin of E. faecalis which consists of two subunits, CylL (large; 68 aas) and CylL (small; 63 aas). They are post-transcriptionally modified by CylM and secreted by the ABC exporter, CylB (TC #3.A.1.111.1). Extracellularly, the two subunits are activated by a protease, CylA yielding the functional mature cytolysin subunits, CylL"L and CylL"S. CylI confers protection to the producer.

The cytolysin is a "pseudohaemolysin" which produces hemolysis on blood agar plates, but not in broth culture. This may be due to regulated synthesis of the cytolysin by an unusual two-component system that senses the extracellular concentration of an inducer via a quorum sensing autoinduction mechanism (Haas et al., 2002). In addition to its toxicity to animal cells, it is bacteriocidal for nearly all Gram-positive bacteria.

This family belongs to the Lantibiotic Bacteriocin (La-Ba) Superfamily.



Haas, W., B.D. Shepard, and M.S. Gilmore. 2002. Two-component regulator of Enterococcus faecalis cytolysin responds to quorum-sensing autoinduction. Nature 415: 84-86.

Hällgren, A., C. Claesson, B. Saeedi, H.J. Monstein, H. Hanberger, and L.E. Nilsson. (2009). Molecular detection of aggregation substance, enterococcal surface protein, and cytolysin genes and in vitro adhesion to urinary catheters of Enterococcus faecalis and E. faecium of clinical origin. Int. J. Med. Microbiol. 299: 323-332.


TC#NameOrganismal TypeExample

Cytolysin, CylLL/CylLS (Hällgren et al. 2009).

Gram-positive bacteria

CylLL and CylLS of Enterococcus species


Type 2 lantibiotic of 61 aas and 1 TM

Lantibiotic of Lactobacillus reuteri


Type 2 lantibiotic, SP_1948 family of 132 aas and 1 TMS.

Lantibiotic of Pilibacter termitis


Type 2 lantibiotic of 56 aas and 1 TM

Lantibiotic of Pilibacter termitis


Type 2 lantibiotic, partial, of 47 aas and 1 TM

Lantibiotic of Geobacillus yumthangensis


Type 2 lantibiotic of 60 aas and 1 TM

Lantibiotic of Ruminococcus gnavus


Type 2 lantibiotic of 62 aas and 1 TMS

Lantibiotic of Eubacterium plexicaudatum ASF492


Type 2 lantibiotic of 53 aas and 1 TM

Lantibiotic of Bacillus thuringiensis


Mersacidin/lichenicidin family type 2 lantibiotic, partial, of 74 aas and 1 TMS.

Lantibiotic of Bacillus cereus


Type 2 lantibiotic of 106 aas and 1 TM

Lantibiotic of Lactobacillus gastricus


Type 2 lantibiotic, SP_1948 family of 78 aas and 1 TM

Lantibiotic of Mycobacteroides abscessus


Type 2 lantibiotic of 70 aas and 1 TM

Lantibiotic of an unclassified Actinomyces specie


Type 2 lantibiotic of 69 aas and 1 TMS.

Lantibiotic of Robinsoniella sp.


Uncharacterized protein of 62 aas and 1 TMS

UP of Paenibacillus zanthoxyli


TC#NameOrganismal TypeExample

Uncharacterized protein of 71 aas and 1 TM

UP of Lachnospira pectinoschiza


Uncharacterized protein of 59 aas and 1 TMS

UP of Planococcus maitriensis


Uncharacterized protein of 63 aas and 1 TMS.

UP of Lachnospira pectinoschiza