Zinc dependent phospholipase C

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Alpha toxin of Clostridium

Identifiers

Symbol Zn_dep_PLPC

Available PDB structures:

1khoA:29-278 1olpB:29-278 1p5xA:39-282 1p6dA:39-282 1ah7 :39-282 1p6eA:39-282

Zinc dependent prokaryotic phospholipases C is a family of bacterial phospholipases C, some of which are also known as alpha toxins.

Bacillus cereus contains a monomeric phospholipase C EC 3.1.4.3 (PLC) of 245 amino-acid residues. Although PLC prefers to acton phosphatidylcholine, it also shows weak catalytic activity with sphingomyelin and phosphatidylinositol^[1]. Sequence studies have shown the protein to be similar both to alpha toxin fromClostridium perfringens and Clostridium bifermentans, a phospholipase C involved in haemolysis and cell rupture^[2], and to lecithinase from Listeria monocytogenes, which aids cell-to-cell spread by breaking down the 2-membrane vacuoles that surround the bacterium during transfer^[3].

Each of these proteins is a zinc-dependent enzyme, binding 3 zinc ions per molecule^[4]. The enzymes catalyse the conversion of phosphatidylcholine and water to 1,2-diacylglycerol and choline phosphate^[1]^[2]^[4].

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.

[edit] References

^ ^a ^b Nakamura S, Yamada A, Tsukagoshi N, Udaka S, Sasaki T, Makino S, Little C, Tomita M, Ikezawa H (1988). "Nucleotide sequence and expression in Escherichia coli of the gene coding for sphingomyelinase of Bacillus cereus". Eur. J. Biochem. 175 (2): 213â€“220. doi:10.1111/j.1432-1033.1988.tb14186.x. PMID 2841128. ^ ^a ^b Titball RW, Rubidge T, Hunter SE, Martin KL, Morris BC, Shuttleworth AD, Anderson DW, Kelly DC (1989). "Molecular cloning and nucleotide sequence of the alpha-toxin (phospholipase C) of Clostridium perfringens". Infect. Immun. 57 (2): 367â€“376. PMID 2536355. ^ Kocks C, Dramsi S, Ohayon H, Geoffroy C, Mengaud J, Cossart P, Vazquez-Boland JA (1992). "Nucleotide sequence of the lecithinase operon of Listeria monocytogenes and possible role of lecithinase in cell-to-cell spread". Infect. Immun. 60 (1): 219â€“230. PMID 1309513. ^ ^a ^b Titball RW, Rubidge T (1990). "The role of histidine residues in the alpha toxin of Clostridium perfringens". FEMS Microbiol. Lett. 56 (3): 261â€“265. doi:10.1111/j.1574-6968.1988.tb03188.x. PMID 2111259.