Structural consequences of carboxyamidation of dermaseptin S3

Deborah E. Shalev, Amram Mor, Irina Kustanovich*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

59 Scopus citations

Abstract

Animal-derived antimicrobial peptides are gaining increasing interest for their role in the innate immune system and for their potential applications in the antimicrobial field. Defining the factors that affect potency and selectivity is presently a major challenge to their effective and safe use. Since amidating the C-terminal carboxyl is one of the means of enhancing antimicrobial activity, we report here our comparative study of the solution structures of the antimicrobial peptide dermaseptin S3 and its amidated analogue. Circular dichroism measurements suggested that the peptides are basically found in an α-helical structure. In contrast, NMR measurements revealed the complete absence of α-helical elements in S3 and a single four-residue helix in the amidated analogue. Whereas the native peptide was found to be flexible, containing a hydrogen-bonded turn and bends, the amidated analogue exhibited a defined α-helix at the C-terminal region, causing the latter to be significantly elongated and more structured. Hence, although the increased potency in amidated antimicrobial peptides can be attributed to the increased overall positive charge, in this case, amidation has had additional effects beyond modifying the net positive charge. It has induced and/or stabilized a helical conformation, causing the amidated dermaseptin to be more rigid and more extended than its nonamidated analogue. The possible implications on the mode of action are discussed herein.

Original languageAmerican English
Pages (from-to)7312-7317
Number of pages6
JournalBiochemistry
Volume41
Issue number23
DOIs
StatePublished - 11 Jun 2002

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