Genetic characterization and heterologous expression of brochocin-C, an antibotulinal, two-peptide bacteriocin produced by Brochothrix campestris ATCC 43754.
Brochocin-C, produced by Brochothrix campestris ATCC 43754, is active against many strains of the closely related meat spoilage organism Brochothrix thermosphacta and a wide range of other gram-positive bacteria, including spores of Clostridium botulinum. Purification of the active compound and genetic characterization of brochocin-C revealed that it is a chromosomally encoded, two-peptide nonlantibiotic bacteriocin. Both peptides of brochocin-C are ribosomally synthesized as prepeptides that are typical of class II bacteriocins. They are cleaved following Gly-Gly cleavage sites to yield the mature peptides, BrcA and BrcB, containing 59 and 43 amino acids, respectively. Fusion of the nucleotides encoding the signal peptide of the bacteriocin divergicin A in front of the structural genes for either BrcA or BrcB allowed independent expression of each component by the general protein secretion pathway. This revealed the two-component nature of brochocin-C and the necessity for both peptides for activity. A 53-amino-acid peptide encoded downstream of brcB functions as the immunity protein (BrcI) for brochocin-C. In addition, the cloned chromosomal fragment revealed open reading frames downstream of brcI, designated brcT and brcD, that encode proteins with homology to ATP-binding cassette translocator and accessory proteins, respectively, involved in the secretion of Gly-Gly-type bacteriocins.
McCormick
J K
JK
Departments of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2P5.
Poon
A
A
Sailer
M
M
Gao
Y
Y
Roy
K L
KL
McMullen
L M
LM
Vederas
J C
JC
Stiles
M E
ME
Van Belkum
M J
MJ
D000595:Amino Acid Sequence; D000818:Animals; D001430:Bacteriocins / Q000737:chemistry / Q000235:genetics* / Q000494:pharmacology; D001483:Base Sequence; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D006090:Gram-Negative Bacteria / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects / Q000235:genetics*; D008460:Meat / Q000382:microbiology; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D015183:Restriction Mapping
D001430:Bacteriocins; C116792:brochocin C