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* Prokaryotic zinc-dependent phospholipase C signature *
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Bacillus cereus expresses  a phosphatidylcholine  hydrolyzing  phospholipase C
(EC 3.1.4.3) (PLC) which  is a  monomeric  protein  of 245 amino-acid residues
that binds three zinc ions [1].  This  PLC is  highly similar to the following
proteins:

 - Alpha-toxin from Clostridium  perfringens and bifermentans  which  are also
   zinc-dependent phospholipases C [2].
 - Lecithinase C from Listeria monocytogenes [3].

In Bacillus  cereus,  there  are nine residues known to be involved in binding
the zinc ions: 5 His, 2 Asp, 1 Glu and 1 Trp. These residues are all conserved
in the Clostridium alpha-toxin.

As a signature pattern  for  this  family  of enzymes, we selected a conserved
region of 11 residues  that  contains  three  of the zinc ligands: a histidine
involved in  binding the first zinc ion, an aspartic acid which binds both the
first and the third zinc ion, and a histidine which binds the second zinc ion.

-Consensus pattern: H-Y-x-[GT]-D-[LIVM]-[DNS]-x-P-x-H-[PA]-x-N
                    [The two H's and the D bind zinc]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in SWISS-PROT: NONE.
-Last update: June 1994 / Pattern and text revised.

[ 1] Hough E., Hansen L.K., Birknes B., Jynge K., Hansen S., Hordvik A.,
     Little C., Dodson E., Derewenda Z.
     Nature 338:358-360(1989).
[ 2] Titball R.W., Rubidge T.
     FEMS Microbiol. Lett. 68:261-266(1990).
[ 3] Vazquez-Boland J.-A., Kocks C., Dramsi S., Ohayon H., Geoffroy C.,
     Mengaud J., Cossart P.
     Infect. Immun. 60:219-230(1992).