Isolation and characterization of carnocyclin a, a novel circular bacteriocin produced by Carnobacterium maltaromaticum UAL307.
Carnobacterium maltaromaticum UAL307, isolated from fresh pork, exhibits potent activity against a number of gram-positive organisms, including numerous Listeria species. Three bacteriocins were isolated from culture supernatant, and using matrix-assisted laser desorption ionization-time of flight mass spectrometry and Edman sequencing, two of these bacteriocins were identified as piscicolin 126 and carnobacteriocin BM1, both of which have previously been described. The remaining bacteriocin, with a molecular mass of 5,862 Da, could not be sequenced by traditional methods, suggesting that the peptide was either cyclic or N-terminally blocked. This bacteriocin showed remarkable stability over a wide temperature and pH range and was unaffected by a variety of proteases. After digestion with trypsin and alpha-chymotrypsin, the peptide was de novo sequenced by tandem mass spectrometry and a linear sequence deduced, consisting of 60 amino acids. Based on this sequence, the molecular mass was predicted to be 5,880 Da, 18 units higher than the observed molecular mass, which suggested that the peptide has a cyclic structure. Identification of the genetic sequence revealed that this peptide is circular, formed by a covalent linkage between the N and C termini following cleavage of a 4-residue peptide leader sequence. The results of structural studies suggest that the peptide is highly structured in aqueous conditions. This bacteriocin, named carnocyclin A, is the first reported example of a circular bacteriocin produced by Carnobacterium spp.
Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada.
Leah A
LA
Martin-Visscher
Marco J
MJ
van Belkum
Sylvie
S
Garneau-Tsodikova
Randy M
RM
Whittal
Jing
J
Zheng
Lynn M
LM
McMullen
John C
JC
Vederas
D000818:Animals; D001430:Bacteriocins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D001483:Base Sequence; D002942:Circular Dichroism; D017931:DNA Primers; D006094:Gram-Positive Bacteria / Q000302:isolation & purification / Q000378:metabolism*; D008460:Meat / Q000382:microbiology; D008969:Molecular Sequence Data; D010456:Peptides, Cyclic / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013211:Staphylococcus aureus / Q000302:isolation & purification / Q000378:metabolism; D013552:Swine
D001430:Bacteriocins; D017931:DNA Primers; D010456:Peptides, Cyclic; C531546:carnocyclin A, Carnobacterium maltaromaticum; C470824:piscicolin 126; C086962:bacteriocin BM1 protein, Carnobacterium piscicola