Structure and Biological Activity of Chemically Modified Nisin A Species

Abstract

(Received 21 May112 August 19Y6) -EJB 96 074213Nisin, a 34-residue peptide bacteriocin, contains the less common amino acids lanthionine, p-methyllanthionine, dehydroalanine (Dha), and dehydrobutyrine (Dhb). Several chemically modified nisin A species were purified by reverse-phase HPLC and characterized by two-dimensional NMR and electrospray mass spectrometry. Five constituents, [2-hydroxy-AlaS]nisin, [Tle4-amide,pyruvyl-Leu6Jdes-Dha5-nisin, [Met(0)2l]nisin, [Ser33]nisin, and nisin-(I -32)-peptide amide, were found in a commercial nisin sample. A further species, [2-hydroxy-AIaS]nisin-( 1 -32)-peptide amide, was obtained by freeze drying an acidic nisin solution. These compounds are formed by chemical modification of nisin: the addition of a water molecule to the dehydroalanine residues, which can lead to the cleavage of the polypeptide chain, or the oxidation of methionine residues.The 2-hydroxyalanine-containing products have a limited stability; they are spontaneously converted into the corresponding des-dehydroalanine derivatives. The growth-inhibiting activity of the modified nisins towards different bacteria was determined. The 2-hydroxyalanine-containing species and the desdehydroalanine derivative show a strong reduction in biological activity as compared to native nisin.[Met(0)2l]nisin and [Ser33]nisin show moderate or no reduction in biological activity.

Isolation and Thermal Stabilization of Bacteriocin Nisin Derived from Whey for Antimicrobial Modifications of Polymers

“…These results are principally in agreement with the work published by Rollema et al [30] who reported chemical stability of nisin A at 20, 37, and 75 ∘ C in various buffers at pH range from 2 to 8. The nisin stability after 3 months of storage at 20…”

Effects of Lactococcus lactis on Composition of Intestinal Microbiota: Role of Nisin

“…In the upper part of the intestinal tract (duodenum and ileum), the nisin concentrations estimated by ELISA were approximately 10-fold higher than those estimated by the bioassay, while in fecal samples, the difference was around 200-fold (Table 2). This indicates that degradation or inactivation of nisin occurs in the GI tract, since proteolytic fragments of nisin will be detected in the competitive ELISA (3), while a nearly intact nisin molecule is needed to retain biological activity (25). Nisin is reported to undergo proteolytic degradation mediated by the pancreas enzyme ␣-chymotrypsin present in the GI tract (10).…”

Chemical Modification of Dehydrated Amino Acids in Natural Antimicrobial Peptides by Photoredox Catalysis

“…a) Schematic representation of the photocatalytic modification of nisin; b) MALDI‐TOF measurement of the crude product of the photocatalytic modification of nisin with 2 a I) degraded Nisin(CH 2 OPhOMe) 2 due to water addition followed by hydrolytic cleavage of the C‐terminal region,13 II) Nisin(CH 2 OPhOMe) 2 , III) Nisin(CH 2 OPhOMe) 3 .…”