Title
Antimicrobial activity of lysozyme isoforms: Key molecular features
Author
Melanie Derde, Véronique Vié, Astrid Walrant, Sandrine Sagan, Valérie Lechevalier, Catherine Guérin-Dubiard, Stéphane Pezennec, Marie-Françoise Cochet, Gilles Paboeuf, Maryvonne Pasco, Florence Baron, Michel Gautier, Sophie Jan, Françoise Nau
Year
2017
Journal
Biopolymers
Abstract
Increasing bacterial resistance towards antibiotics has stimulated research for novel antimicrobials. Proteins acting on bacterial membranes could be a solution. Lysozyme has been proven active against E. coli by disruption of both outer and cytoplasmic membranes, with dry-heating increasing lysozyme activity. Dry-heated lysozyme (DH-L) is a mixture of isoforms (isoaspartyl, native-like and succinimide lysozymes), giving rise to two questions: what effects does each form have, and which physicochemical properties are critical as regards the antibacterial activity? These issues were investigated by fractionating DH-L, analyzing structural properties of each fraction, and testing each fraction in vivo on bacteria and in vitro on membrane models. Positive net charge, hydrophobicity and molecular flexibility of the isoforms seem key parameters for their interaction with E. coli membranes. The succinimide lysozyme fraction, the most positive, flexible and hydrophobic, shows the highest antimicrobial activity, induces the strongest bacterial membrane disruption and is the most surface active on model lipid monolayers. Moreover, each fraction appears less efficient than DH-L against E. coli, indicating a synergetic cooperation between lysozyme isoforms. The bacterial membrane modifications induced by one isoform could facilitate the subsequent action of the other isoforms.
Instrument
J-815
Keywords
Circular dichroism, Secondary structure, Tertiary structure, Biochemistry, Polymers