Identification and Characterization of Two Novel Clostridial Bacteriocins, Circularin A and Closticin 574 |
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Authors: | Robr Kemperman Anneke Kuipers Harma Karsens Arjen Nauta Oscar Kuipers and Jan Kok |
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Institution: | Robèr Kemperman, Anneke Kuipers, Harma Karsens, Arjen Nauta, Oscar Kuipers, and Jan Kok |
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Abstract: | Two novel antibacterial peptides of clostridial species were purified, N-terminally sequenced, and characterized. Moreover, their structural genes were identified. Closticin 574 is an 82-amino-acid bacteriocin produced by Clostridium tyrobutyricum ADRIAT 932. The supernatant of the producing strain showed a high level of activity against the indicator strain C. tyrobutyricum. The protein is synthesized as a preproprotein that is possibly secreted via the general secretion pathway, after which it is hydrolyzed at an Asp-Pro site. Circularin A is produced by Clostridium beijerinckii ATCC 25752 as a prepeptide of 72 amino acids. Cleavage of the prepeptide between the third leucine and fourth valine residues followed by a head-to-tail ligation between the N and C termini creates a circular antimicrobial peptide of 69 amino acids. The unusually small circularin A leader peptide of three amino acids is cleaved off in this process. The supernatant of C. beijerinckii ATCC 25752 showed a broad antibacterial activity range. |
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