Membrane-Mimicking Entities Induce Structuring of the Two-Peptide Bacteriocins Plantaricin E/F and Plantaricin J/K

Abstract

Lactobacillus plantarum C11 produces plantaricin E/F (PlnE/F) and plantaricin J/K (PlnJ/K), two bacteriocins whose activity depends on the complementary action of two peptides (PlnE and PlnF; PlnJ and PlnK). Three of the individual Pln peptides possess some antimicrobial activity, but the highest bacteriocin activity is obtained by combining complementary peptides in about a one-to-one ratio. Circular dichroism was used to study the structure of the Pln peptides under various conditions. All four peptides were unstructured under aqueous conditions but adopted a partly alpha-helical structure in the presence of trifluoroethanol, micelles of dodecylphosphocholine, and negatively charged dioleoylphosphoglycerol (DOPG) liposomes. Far less structure was induced by zwitterionic dioleoylglycerophosphocholine liposomes, indicating that a net negative charge on the phospholipid bilayer is important for a structure-inducing interaction between (positively charged) Pln peptides and a membrane. The structuring of complementary peptides was considerably enhanced when both (PlnE and PlnF or PlnJ and PlnK) were added simultaneously to DOPG liposomes. Such additional structuring was not observed in experiments with trifluoroethanol or dodecylphosphocholine, indicating that the apparent structure-inducing interaction between complementary Pln peptides requires the presence of a phospholipid bilayer. The amino acid sequences of the Pln peptides are such that the alpha-helical structures adopted upon interaction with the membrane and each other are amphiphilic in nature, thus enabling membrane interactions.

Colorectal cancer specific conditions promote Streptococcus gallolyticus gut colonization

“…S1). In addition, detergents are known activators of these bacteriocins, as they provide a membrane-like scaffold allowing proper α-helical folding of the two interacting hydrophobic peptides (23,(34)(35)(36).…”

A synthetic analog of plantaricin 149 inhibiting food‐borne pathogenic bacteria:evidence for α‐helical conformation involved in bacteria–membrane interaction

“…However, only a few have been purified and sequenced. With the exception of plantaricin A [6], plantaricin E/F, plantaricin J/K [7], and plantaricin C [8], information on the secondary structure of L. plantarum bacteriocins is still scarce.…”

Complementary and Overlapping Selectivity of the Two-Peptide Bacteriocins Plantaricin EF and JK

“…Likewise, PlnJ and PlnK are efficient antimicrobials when present together. Strikingly, none of the other combinations of these four peptides enhanced the antimicrobial activity (2,8). The amphiphilic structure of these peptides is believed to play a role in pore formation (8,9).…”

“…PlnE, PlnF, PlnJ, and PlnK are cationic peptides that consist of 33, 34, 25, and 32 amino acids and have molecular weights of 3,703, 3,545, 2,929, and 3,503, respectively (5). These pep-tides have the propensity to form an amphiphilic ␣-helical structure in a membrane-mimicking environment (8). The antimicrobial activity of PlnF is enhanced more than 1,000-fold by the equimolar presence of PlnE and vice versa.…”

“…Strikingly, none of the other combinations of these four peptides enhanced the antimicrobial activity (2,8). The amphiphilic structure of these peptides is believed to play a role in pore formation (8,9). The complementary peptides (PlnEF or PlnJK) interact, because the simultaneous addition of both of the peptides synergistically promoted the formation of their ␣-helical structure in the presence of dioleoylphosphatidylglycerol liposomes (8).…”