Improved Antimicrobial Activities of Synthetic-Hybrid Bacteriocins Designed from Enterocin E50-52 and Pediocin PA-1

Abstract

c Two hybrid bacteriocins, enterocin E50-52/pediocin PA-1 (EP) and pediocin PA-1/enterocin E50-52 (PE), were designed by combining the N terminus of enterocin E50-52 and the C terminus of pediocin PA-1 and by combining the C terminus of pediocin PA-1 and the N terminus of enterocin E50-52, respectively. Both hybrid bacteriocins showed reduced MICs compared to those of their natural counterparts. The MICs of hybrid PE and EP were 64-and 32-fold lower, respectively, than the MIC of pediocin PA-1 and 8-and 4-fold lower, respectively, than the MIC of enterocin E50-52. In this study, the effect of hybrid as well as wildtype (WT) bacteriocins on the transmembrane electrical potential (⌬⌿) and their ability to induce the efflux of intracellular ATP were investigated. Enterocin E50-52, pediocin PA-1, and hybrid bacteriocin PE were able to dissipate ⌬⌿, but EP was unable to deplete this component. Both hybrid bacteriocins caused a loss of the intracellular concentration of ATP. EP, however, caused a faster efflux than PE and enterocin E50-52. Enterocin E50-52 and hybrids PE and EP were active against the Gram-positive and Gram-negative bacteria tested, such as Micrococcus luteus, Salmonella enterica serovar Enteritidis 20E1090, and Escherichia coli O157:H7. The hybrid bacteriocins designed and described herein are antimicrobial peptides with MICs lower those of their natural counterparts. Both hybrid peptides induce the loss of intracellular ATP and are capable of inhibiting Gram-negative bacteria, and PE dissipates the electrical potential. In this study, the MIC of hybrid bacteriocin PE decreased 64-fold compared to the MIC of its natural peptide counterpart, pediocin PA-1. Inhibition of Gram-negative pathogens confers an additional advantage for the application of these peptides in therapeutics. Bacteriocins are membrane-permeating, mostly cationic, ribosomally synthesized antimicrobial peptides (AMPs) produced by bacteria (1). These peptides are synthesized together with cognate immunity proteins in order to render the bacteriocin-producing bacteria resistant to their own bacteriocins (2-4). Bacteriocins produced by lactic acid bacteria (LAB) have been extensively studied by the use of genetic modification and protein engineering due to their potential application as nontoxic food preservatives and therapeutic agents (5). The LAB bacteriocins nisin and pediocin PA-1 are frequently studied and used as food biopreservatives (3, 6). The potential of LAB bacteriocins in medical applications is exemplified by previously reported results which indicated that the oral intake of bacteriocin-producing LAB protects mice from lethal doses of Listeria monocytogenes (7). Therefore, LAB bacteriocins are the logical alternative to clinical antibiotics (8) and/or may help to enhance the efficacy of current antibiotics (9, 10).All pediocin-like bacteriocins contain disulfide bridges and a common YGNG(V/L) motif (pediocin box) which forms an Sshaped, sheet-like structure followed by a hinge and a somewhat more hydrophobic and diverse ...

Synthesis, antimicrobial activity and conformational analysis of the class IIa bacteriocin pediocin PA-1 and analogs thereof

“…No strains lying outside the phylogenetic tree or with a high degree of similarity showed sensitivity to the synthetic analog 4 (Table S1 ). Antimicrobial activity of pediocin PA-1 against Micrococcus luteus has been reported recently 49 . However, we found no activity against M. luteus ATCC 10240 for synthetic pediocin PA-1 3c or its analogs at up to 100 µM.…”

Bacteriocins and their position in the next wave of conventional antibiotics

“…Hybridisation of bacteriocins has also indicated increased efficacy in the case of eneterocin E50/pediocin PA-1 and pediocin PA-1/enterocin E50-52 in that MICs were reduced by 32-fold and 64-fold, respectively, compared with their natural counterparts, as tested against various Gram-positive and Gram-negative bacteria [89].…”

Peptide Bacteriocins - Structure Activity Relationships

“…Recently, two hybrid bacteriocins, enterocin E50-52/pediocin PA-1 and pediocin PA-1/enterocin E50-52 designed by switching the C and N terminus domains, showed reduced MICs in comparison to those of their natural counterparts. [108] .…”