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Zinc dependent phospholipase C

Introduction

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.

References

  1. ↑ 1.0 1.1 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): 213–220. PMID 2841128.
  2. ↑ 2.0 2.1 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): 367–376. PMID 2536355.
  3. ↑ 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): 219–230. PMID 1309513.
  4. ↑ 4.0 4.1 Titball RW, Rubidge T (1990). “The role of histidine residues in the alpha toxin of Clostridium perfringens”. FEMS Microbiol. Lett. 56 (3): 261–265. PMID 2111259.
This article incorporates text from the public domain Pfam and InterPro: IPR001531

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