| Class II bacteriocin | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Three-dimensional structure of leucocin A a type IIa bacteriocin.[1] | |||||||||
| Identifiers | |||||||||
| Symbol | Bacteriocin_II | ||||||||
| Pfam | PF01721 | ||||||||
| InterPro | IPR002633 | ||||||||
| PROSITE | PDOC60030 | ||||||||
| SCOP | 3leu | ||||||||
| TCDB | 1.C.24 | ||||||||
| OPM family | 150 | ||||||||
| OPM protein | 1ohm | ||||||||
|
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Class II bacteriocins are a class of small peptides that inhibit the growth of various bacteria.
Many Gram-positive bacteria produce ribosomally synthesized antimicrobial peptides, termed bacteriocins.
Bacteriocins for which disulfide bonds are the only modification to the peptide are Class II bacteriocins.
Contents |
One important and well studied class of bacteriocins is the class IIa or pediocin-like bacteriocins produced by lactic acid bacteria. All class IIa bacteriocins are produced by food-associated strains, isolated from a variety of food products of industrial and natural origins, including meat products, dairy products and vegetables. Class IIa bacteriocins are all cationic, display anti-Listeria activity, and kill target cells by permeabilizing the cell membrane[2][3][4].
Class IIa bacteriocins contain between 37 and 48 residues[5]. Based on their primary structures, the peptide chains of class IIa bacteriocins may be divided roughly into two regions: a hydrophilic, cationic and highly conserved N-terminal region, and a less conserved hydrophobic/amphiphilic C-terminal region. The N-terminal region contains the conserved Y-G-N-G-V/L 'pediocin box' motif and two conserved cysteine residues joined by a disulfide bridge. It forms a three-stranded antiparallel beta-sheet supported by the conserved disulfide bridge. This cationic N-terminal beta-sheet domain mediates binding of the class IIa bacteriocin to the target cell membrane. The C-terminal region forms a hairpin-like domain that penetrates into the hydrophobic part of the target cell membrane, thereby mediating leakage through the membrane. The two domains are joined by a hinge, which enables movement of the domains relative to each other[3][4].
Some proteins known to belong to the class IIa bacteriocin family are listed below:
The class IIb bacteriocins (two-peptide bacteriocins) require two different peptides for activity.
Other class II bacteriocins can be grouped together as Class IIc (circular bacteriocins). These have a wide range of effects on membrane permeability, cell wall formation and pheromone actions of target cells.
This article incorporates text from the public domain Pfam and InterPro IPR002633