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Virtual screening of a milk peptide database for the identification of food‐derived antimicrobial peptides
Author(s) -
Liu Yufang,
Eichler Jutta,
Pischetsrieder Monika
Publication year - 2015
Publication title -
molecular nutrition and food research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.495
H-Index - 131
eISSN - 1613-4133
pISSN - 1613-4125
DOI - 10.1002/mnfr.201500182
Subject(s) - antimicrobial , antimicrobial peptides , peptide , bacillus subtilis , escherichia coli , chemistry , minimum inhibitory concentration , biochemistry , casein , bacteria , food science , biology , microbiology and biotechnology , genetics , gene
Scope Milk provides a wide range of bioactive substances, such as antimicrobial peptides and proteins. Our study aimed to identify novel antimicrobial peptides naturally present in milk. Methods and results The components of an endogenous bovine milk peptide database were virtually screened for charge, amphipathy, and predicted secondary structure. Thus, 23 of 248 screened peptides were identified as candidates for antimicrobial effects. After commercial synthesis, their antimicrobial activities were determined against Escherichia coli NEB5α, E. coli ATCC25922, and Bacillus subtilis ATCC6051. In the tested concentration range (<2 mM), bacteriostatic activity of 14 peptides was detected including nine peptides inhibiting both Gram‐positive and Gram‐negative bacteria. The most effective fragment was TKLTEEEKNRLNFLKKISQRYQKFΑLPQYLK corresponding to α S2 ‐casein 151–181 , with minimum inhibitory concentration (MIC) of 4.0 μM against B. subtilis ATCC6051, and minimum inhibitory concentrations of 16.2 μM against both E. coli strains. Circular dichroism spectroscopy revealed conformational changes of most active peptides in a membrane‐mimic environment, transitioning from an unordered to α‐helical structure. Conclusion Screening of food peptide databases by prediction tools is an efficient method to identify novel antimicrobial food‐derived peptides. Milk‐derived antimicrobial peptides may have potential use as functional food ingredients and help to understand the molecular mechanisms of anti‐infective milk effects.