Simple parameterization of non-proteinogenic amino acids for QSAR of antibacterial peptides.

The antibacterial activity of bovine lactoferricin-(17-31)-pentadecapeptide against Escherichia coli and Staphylococcus aureus is sensitive to substitution of the Trp residues, and synthetic peptides with phenylalanine and any of eight non-proteinogenic aromatic amino acids greatly affected antibiotic activity. Using simple size-related descriptors for the new amino acids it is possible to develop quantitative structure-activity relationships (QSARs) that can be used as tools in the search for more active peptides.