A Novel High-Molecular-Mass Bacteriocin Produced by Enterococcus faecium: Biochemical Features and Mode of Action

• Published in: Probiotics and antimicrobial proteins Vol. 10; no. 3; pp. 427 - 434
• Main Authors: Vasilchenko, A. S., Vasilchenko, A.V., Valyshev, A.V., Rogozhin, E.A.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-09-2018
• Subjects: Applied Microbiology; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Microbiology; Nutrition; Protein Science; Enterocin; Liquid chromatography; Class III; Bacteriocin; Antimicrobial peptides; Enterococcus
• ISSN: 1867-1306; 1867-1314
• DOI: 10.1007/s12602-018-9392-0

Discovery of a novel bacteriocin is always an event in sciences, since cultivation of most bacterial species is a general problem in microbiology. This statement is reflected by the fact that number of bacteriocins is smaller for tenfold comparing to known antimicrobial peptides. We cultivated
Enterococcus faecium
on simplified medium to reduce amount of purification steps. This approach allows to purify the novel heavy weight bacteriocin produced by
E. faecium
ICIS 7. The novelty of this bacteriocin, named enterocin-7, was confirmed by N-terminal sequencing and by comparing the structural-functional properties with available data. Purified enterocin-7 is characterized by a sequence of amino acid residues having no homology in UniProt/SwissProt/TrEMBL databases: NH2 - Asp - Ala - His - Leu - Ser - Glu - Val - Ala - Glu - Arg - Phe - Glu - Asp - Leu - Gly. Isolated thermostable protein has a molecular mass of 65 kDa, which allows it to be classified into class III in bacteriocin classification schemes. Enterocin-7 displayed a broad spectrum of activity against some Gram-positive and Gram-negative microorganisms. Fluorescent microscopy and spectroscopy showed the permeabilizing mechanism of the action of enterocin-7, which is realized within a few minutes.