Characterization of a new bacteriocin, Carocin D, from Pectobacterium carotovorum subsp. carotovorum Pcc21.
Two different bacteriocins, carotovoricin and carocin S1, had been found in Pectobacterium carotovorum subsp. carotovorum, which causes soft-rot disease in diverse plants. Previously, we reported that the particular strain Pcc21, producing only one high-molecular-weight bacteriocin, carried a new antibacterial activity against the indicator strain Pcc3. Here, we report that this new antibacterial activity is due to a new bacteriocin produced by strain Pcc21 and named carocin D. Carocin D is encoded by the caroDK gene located in the genomic DNA together with the caroDI gene, which seems to encode an immunity protein. N-terminal amino acid sequences of purified carocin D were determined by Edman degradation. In comparison with the primary translation product of caroDK, it was found that 8 amino acids are missing at the N terminus. This finding proved that carocin D is synthesized as a precursor peptide and that 8 amino acids are removed from its N terminus during maturation. Carocin D has two putative translocation domains; the N-terminal and C-terminal domains are homologous to those of Escherichia coli colicin E3 and Pseudomonas aeruginosa S-type pyocin, respectively. When caroDK and caroDI genes were transformed into carocin D-sensitive bacteria such as Pcc3, the bacteria became resistant to this bacteriocin. Carocin D has one putative DNase domain at the extreme C terminus and showed DNase activity in vitro. This bacteriocin had slight tolerance to heat but not to proteases. The caroDK gene was present in only 5 of 54 strains of P. carotovorum subsp. carotovorum. These results indicate that carocin D is a third bacteriocin found in P. carotovorum subsp. carotovorum, and this bacteriocin can be readily expressed in carocin D-sensitive nonpathogenic bacteria, which may have high potential as a biological control agent in the field.
Roh
Eunjung
E
Microbial Safety Division, National Academy of Agricultural Science, Rural Development Administration, Suwon 441-707, South Korea.
Park
Tae-Ho
TH
Kim
Myung-Il
MI
Lee
Seungdon
S
Ryu
Sangryeol
S
Oh
Chang-Sik
CS
Rhee
Sangkee
S
Kim
Doo-Ho
DH
Park
Beom-Seok
BS
Heu
Sunggi
S
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000302:isolation & purification* / Q000378:metabolism; D001430:Bacteriocins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D003851:Deoxyribonucleases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D005798:Genes, Bacterial; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D016973:Pectobacterium carotovorum / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D020539:Sequence Analysis, Protein
D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D004269:DNA, Bacterial; D003851:Deoxyribonucleases