Structure-activity relationship study of the antimicrobial CRAMP-derived peptide CRAMP20-33.

We report here on the structure-activity relationship study of a 14 amino acid fragment of the cathelicidin-related antimicrobial peptide (CRAMP), CRAMP20-33 (KKIGQKIKNFFQKL). It showed activity against Escherichia coli and filamentous fungi with IC values below 30 μM and 10 μM, respectively. CRAMP20-33 variants with glycine at position 23 substituted by phenylalanine, leucine or tryptophan showed 2- to 4-fold improved activity against E.