Bacillus cereus contains a monomeric phospholipase C EC:3.1.4.3 (PLC) of 245 amino-acid residues that binds three zinc ions [ PUBMED:2493587 ]. Although PLC prefers to act on phosphatidylcholine, it also shows weak catalytic activity with sphingomyelin … expand

Bacillus cereus contains a monomeric phospholipase C EC:3.1.4.3 (PLC) of 245 amino-acid residues that binds three zinc ions [ PUBMED:2493587 ]. Although PLC prefers to act on phosphatidylcholine, it also shows weak catalytic activity with sphingomyelin and phosphatidylinositol [ PUBMED:2841128 ]. Sequence studies have shown the PLC protein to be similar to the following:

• Alpha toxin from Clostridium perfringens and Clostridium bifermentans, which are zinc-dependent phospholipases C involved in haemolysis and cell rupture [ PUBMED:2536355 ].
• Lecithinase C from Listeria monocytogenes, which aids cell-to-cell spread by breaking down the 2-membrane vacuoles that surround the bacterium during transfer [ PUBMED:1309513 ].

Each of these proteins is a zinc-dependent enzyme, binding 3 zinc ions per molecule [ PUBMED:2111259 ]. The enzymes catalyse the conversion of phosphatidylcholine and water to 1,2-diacylglycerol and choline phosphate [ PUBMED:2841128 PUBMED:2536355 PUBMED:2111259 ]. In B. 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 [ PUBMED:9699639 ].