(464f) Antimicrobial Peptide Segments from Soy Protein for Use in Food Safety

Authors: 
Narsimhan, G., Purdue University
Xiang, N., Purdue University
Lyu, Y., Purdue University

Antimicrobial peptides (AMPs) kill microbial cells through insertion and damage/permeabilization of the cytoplasmic cell  membranes and has applications in food safety. Soy protein may be such an attractive, cost-saving candidate for commercial consideration because the protein subunits have amino acid sequences that contain several α-helix or 3-10 helix domains which possess characteristics of AMPs. A methodology for identification  of AMPs from soy protein is proposed.  They were identified  from  soy  β-conglycinin  (7S)  and  glycinin  (11S)  based  on  (i) number of amino acids, (ii) positive  charge, (iii) hydrophobicity and (iv)  hydrophobic moment. Explicit solvent molecular Dynamics (MD) simulation was employed to assess the secondary conformation of these peptides in POPC/POPG bilayers to  mimic  their  permeation  action  on  the cell membrane of microorganism. The effects of number of peptides, their orientation and hydrophobic moment on the deformation of membrane and formation of water channel were investigated. A mathematical model for the prediction of minimum inhibitory concentration for deactivation (antimicrobial activity) was proposed accounting for free energy of formation of a pore by an aggregate of peptides. The antimicrobial activity was tested by using synthetic selected peptides against Listeria monocytogenes and E. Coli and compared with predictions.