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dc.contributor.authorDashper, SG
dc.contributor.authorO'Brien-Simpson, NM
dc.contributor.authorCross, KJ
dc.contributor.authorPaolini, RA
dc.contributor.authorHoffmann, B
dc.contributor.authorCatmull, DV
dc.contributor.authorMalkoski, M
dc.contributor.authorReynolds, EC
dc.identifierpii: 49/6/2322
dc.identifier.citationDashper, S. G., O'Brien-Simpson, N. M., Cross, K. J., Paolini, R. A., Hoffmann, B., Catmull, D. V., Malkoski, M. & Reynolds, E. C. (2005). Divalent metal cations increase the activity of the antimicrobial peptide kappacin. ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, 49 (6), pp.2322-2328.
dc.descriptionC1 - Journal Articles Refereed
dc.description.abstractKappacin, nonglycosylated kappa-casein(106-169), is a novel antimicrobial peptide produced from kappa-casein found in bovine milk. There are two major genetic forms of kappacin, A and B, and using synthetic peptides corresponding to the active region, kappa-casein(138-158), of these forms, we have shown that the Asp148 to Ala148 substitution is responsible for the lesser antibacterial activity of kappa-casein-B(106-169). Kappacin was shown to have membranolytic action at concentrations above 30 microM at acidic pH when tested against artificial liposomes. There was little membranolytic activity at neutral pH, which is consistent with the lack of antibacterial activity of kappacin against Streptococcus mutans at this pH. Kappacin specifically bound two zinc or calcium ions per mol, and this binding enhanced antibacterial activity at neutral pH. Nuclear magnetic resonance analysis indicated that a kappa-casein-A(138-158) synthetic peptide undergoes a conformational change in the presence of the membrane solvent trifluoroethanol and excess divalent metal ions. This change in conformation is presumably responsible for the increase in antibacterial activity of kappacin detected in the presence of excess zinc or calcium ions at neutral pH. When tested against the oral bacterial pathogen S. mutans cultured as a biofilm in a constant-depth film fermentor, a preparation of 10 g/liter kappacin and 20 mM ZnCl2 reduced bacterial viability by 3 log10 and suppressed recovery of viability. In contrast 20 mM ZnCl2 alone reduced bacterial viability by approximately 1 log10 followed by rapid recovery. In conclusion, kappacin has a membranolytic, antibacterial effect that is enhanced by the presence of divalent cations.
dc.subjectAnalytical Biochemistry; Bacteriology ; Prevention - Biologicals (e.g. Vaccines); Treatments (e.g. Chemicals
dc.subjectAntibiotics); Dental Health
dc.titleDivalent metal cations increase the activity of the antimicrobial peptide kappacin
dc.typeJournal Article
melbourne.peerreviewPeer Reviewed
melbourne.affiliationThe University of Melbourne
melbourne.affiliation.departmentDental Science
melbourne.source.titleAntimicrobial Agents and Chemotherapy
melbourne.contributor.authorDashper, Stuart
melbourne.contributor.authorO'Brien-Simpson, Neil
melbourne.contributor.authorCross, Keith
melbourne.contributor.authorPaolini, Rita
melbourne.contributor.authorHoffmann, Brigitte
melbourne.contributor.authorCatmull, Deanne
melbourne.contributor.authorReynolds, Eric
melbourne.contributor.authorMALKOSKI, MARINA
melbourne.accessrightsAccess this item via the Open Access location

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