Abstract: Compositions and methods for making and using modified anti-infective peptides are provided. For example, synthetically and/or recombinantly produced analogues or derivatives of naturally occurring anti-infective peptides may be efficiently modified using the compositions and methods provided herein to generate similar or identical post-translational modifications found in wild-type anti-infective peptides. The modified anti-infective peptides (e.g., antimicrobial cationic peptides) and analogues or derivatives thereof may be used, for example, in the treatment of microorganism-caused infections.