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Antimicrobial Peptides Produced by Selective Pressure Incorporation of Non-canonical Amino Acids
Published on: May 4, 2018
An acidic model pro-peptide affects the secondary structure, membrane interactions and antimicrobial activity of a
Nelson G O Júnior1,2,3, Marlon H Cardoso1,3,4, Elizabete S Cândido1,4
1Centro de Análises Proteômicas e Bioquímicas, Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília-DF, Brazil.
Abstract:
In order to study how acidic pro-peptides inhibit the antimicrobial activity of antimicrobial peptides, we introduce a simple model system, consisting of a 19 amino-acid long antimicrobial peptide, and an N-terminally attached, 10 amino-acid long acidic model pro-peptide. The antimicrobial peptide is a fragment of the crotalicidin peptide, a member of the cathelidin family, from rattlesnake venom. The model pro-peptide is a deca (glutamic acid). Attachment of the model pro-peptide only leads to a moderately large reduction in the binding to- and induced leakage of model liposomes, while the antimicrobial activity of the crotalicidin fragment is completely inhibited by attaching the model pro-peptide. Attaching the pro-peptide induces a conformational change to a more helical conformation, while there are no signs of intra- or intermolecular peptide complexation. We conclude that inhibition of antimicrobial activity by the model pro-peptide might be related to a conformational change induced by the pro-peptide domain, and that additional effects beyond induced changes in membrane activity must also be involved.
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