Biological Activities and Structural Properties of the Atypical Bacteriocins Mesenterocin 52B and Leucocin B-TA33a

Abstract

The antibacterial spectra and modes of action of synthetic peptides corresponding to mesenterocin 52B and leucocin B-TA33a greatly differ despite their high sequence homology. Circular dichroism experiments establish the capacity of each of these two peptides to partly fold into an amphiphilic helix that might be crucial for their adsorption at lipophilic-hydrophilic interfaces.Among the various antimicrobial compounds produced by lactic acid bacteria, bacteriocins are bioactive single polypeptides or polypeptide complexes that are active against closely related bacterial species (14,15,22). These bacteriocins constitute a large family of metabolites, which can be subdivided into different classes based on their modes of action and their structures (14). In particular, class II bacteriocins are small, heat-stable, non-lanthionine-containing peptides, varying between 30 and 60 residues in length (Ͻ10 kDa) (8). Subgroups have been defined within class II, notably the class IIa bacteriocins, which contain a consensus YGNGV amino acid motif near the N terminus and are active against Listeria spp. Within the class IIa bacteriocins produced by some Leuconostoc strains (11,12,18,20), the closely related leucocin A and mesentericin Y105 have been the subject of numerous studies, including conformational ones (9, 10). In low-polarity medium, mesentericin Y105 was found to be partially folded as an amphipathic helix spanning over residues 17 to 31 (9), and leucocin A is proposed to adopt an amphiphilic ␣-helical conformation in its C-terminal region, whereas the N-terminal part would fold into a three-stranded anti-parallel ␤-sheet conformation (10).Within the Leuconostoc genus, some strains have been recently shown to produce more than one bacteriocin. In addition to mesenterocin 52A, which is identical to mesentericin Y105, Leuconostoc mesenteroides subsp. mesenteroides FR52 produces the 32-mer polypeptide mesenterocin 52B (20). The same bacteriocin has also been detected in culture extracts of L. mesenteroides Y105 (1). L. mesenteroides strain TA33a actually produces three different bacteriocins: class IIa leucocin A-TA33a, leucocin B-TA33a, and leucocin C-TA33a, a new anti-Listeria bacteriocin (18,19). It is noteworthy that mesenterocin 52B and leucocin B-TA33a display narrow spectra of activity limited to the genera Leuconostoc and Weissella (18,19,20). Thus, they can be distinguished from other metabolites produced by Leuconostoc sp. strains (11,12,19,20). The primary structures of the two bacteriocins are presented in Table 1. By shifting the mesenterocin 52B sequence forward by two positions, identical amino acids appear in 17 positions and lead to a 63% identity score between the two peptides. The similarity is most obvious in the central domain of the peptide, where the LTGPQQP motif is present in the two bacteriocins. As both mesenterocin 52B and leucocin B-TA33a are small heat-stable and non-lanthionine-containing peptides, their classification as bacteriocins from class II is obvious. Yet, in addition to the...

Complete Amino Acid Sequence of Globin Chains and Biological Activity of Fragmented Crocodile Hemoglobin (Crocodylus siamensis)

“…However, there were contained random coils and extended strands. From the results, it is possible due to these peptides might adopt a helical structure from a random coil while their interaction with membranes [7,29,31,33]. Moreover, peptides a (V1-V13), (K16-A26) and b (A69-S80) are not contain positively charged amino acids but have high hydrophobic property and contain a random coil structure.…”

Leuconostoc, characteristics, use in dairy technology and prospects in functional foods

“…Mesentericin Y105 and B105 and mesenterocin 52A and 52B from dairy Leuconostoc strains have been extensively described and their biological activity, structure and properties have been analysed (Mathieu, Sudirman, Rekhif, Milli" ere, & Lef" ebvre, 1993;Sudirman, Mathieu, Benoit, & Lef" ebvre, 1994;Krier, Revol-Junelles, & Germain, 1998;H! echard, Berjeaud, & Cenatiempo, 1999;Ennahar et al, 2000;Corbier, Krier, Mulliert, Vitoux, & Revol-Junelles, 2001;Morisset & Fr" ere, 2002). The mesentericin Y105 and B105 structural genes, mesY and mesB, respectively were cloned (Fr!…”

Variations in the Membrane Fatty Acid Composition of Resistant or Susceptible Leuconostoc or Weissella Strains in the Presence or Absence of Mesenterocin 52A and Mesenterocin 52B Produced by Leuconostoc mesenteroides subsp. mesenteroides FR52

“…This peptide is atypical, because no class II subclass corresponds to it. The amphipathic and cationic characters and ␣-helix conformation of these peptides are related to their mechanism of action, with the cell membrane as the primary target (3,9,10).…”