Scientific Publications with referee

A C-terminal disulfide bridge in pedicin-like bacteriocins renders bacteriocin activity less temperature dependent and is a major determinant of the antimicrobial spectrum.

 

Melkesyrebakteriers produksjon av bakteriociner, peptider som virker hemmende mot andre bakterier, har vært et forskningsområde på Matforsk i flere år. Denne artikkelen, som er et samarbeid mellom Universitetet i Oslo, Landbrukshøgskolen på Ås og Matforsk, er grunnforskningsrettet og beskriver spesifikke strukturer i peptidkjeden hos bakteriociner i de såkalte pediocinlignende bakteriocinene. Disse er av spesiell interesse fordi de har aktivitet mot den matborne sykdomsfremkallende bakterien Listeria monocytogenes. Pediocinlignende bakteriociner har en eller to disulfidbroer i peptidkjeden. Gjennom molekylær genetiske teknikker, f eks heterolog ekspresjon og rettet mutagenese av strukturgenet til bakteriociner, ble det vist at den C-terminale disulfidbroen spiller en sentral rolle for bakteriocinet aktivitetsspektrum, dvs. hvilke bakterier den virker mot, og for temperaturstabiliteten. I forbindelse med temperaturstabiliteten kan det virke som bakteriocinene er tilpasset produksjonsorganismenes temperaturkrav for vekst.

Facts

Year 2000
Abstract Sveral lactic acid bacteria produce so-called pediocin-like bacteriocins that share sequence characteristics, but differ in activity and target cell specificity. The significance of a C-terminal disulfide bridge present in only a few of these bacteriocins was studied by site-directed mutagenesis of pediocin PA-1 (which naturally contains the bridge) and sakacin P (which lacks the bridge). Introduction of the C-terminal bridge into sakacin P broadened the target cell specificity of this bacteriocin, as illustrated by the fact that the mutants were 10 - 20 times more potent than the wild-type towards certain indicator strains, whereas the potency towards other indicator strains remained essentially unchanged. Like pediocin PA-1, disulfide-containing sakacin P mutants had the same potency at 20 and 37 oC, whereas wildtype sakacin P was approximately 10 times less potent at 37 than 20 oC. Reciprocal effects on target-cell specificity and the temperature-dependence of potency were observed upon studying the effect of removing the C-terminal disulfide bridge from pediocin PA-1 by Cys -> Ser mutations. These results clearly show that a C-terminal disulfide bridge in pediocin-like bacteriocins contributes to widening of the antimicrobial spectrum as well as to higher potency at elevated temperatures. Interestingly, the differences between sakacin P and pediocin PA-1 in terms of the temperature dependency of their activity correlated well with the optimal temperatures for bacteriocin-production and growth of the bacteriocin-producing strain.
Reference Fimland, G., Johnsen, L., Axelsson, L., Brurberg, M.B., Nes, I.F., Eijsink, V.G.H., Nissen-Meyer, J. 2000. A C-terminal disulfide bridge in pedicin-like bacteriocins renders bacteriocin activity less temperature dependent and is a major determinant of the antimicrobial spectrum. Journal of Bacteriology, Vol 182, 9, pp 2643-2648.
Publisher Journal of Bacteriology,

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