Enzymatic installation of post-translational modifications into artificial peptides using RiPP biosynthetic machinery

Post-translational modifications (PTMs) of peptides are promising approaches for introducing desired chemical and biological properties. Nature often employs this strategy in the biosynthesis of bioactive peptidic natural products, which acquire their unique structures and functions through diverse enzymatic conversions. Ribosomally synthesized and post-translationally modified peptides (RiPPs) represent a prominent example and constitute a major group of peptidic natural products generated through various PTMs of ribosomally translated precursor peptides. Owing to their biosynthetic features, RiPP PTM enzymes provide a valuable foundation for peptide bioengineering. Numerous engineering approaches have been developed and have increasingly expanded beyond native RiPP substrates to artificial peptides that substantially diverge from them. Here, we review recent bioengineering approaches that exploit RiPP PTM enzymes for the modification of artificial peptides, including large combinatorial peptide libraries, de novo designed peptides, and chemically synthesized peptides. These advances demonstrate the potential of RiPP biosynthetic machinery as a versatile toolkit for expanding peptide chemical space and generating bioactive artificial peptides.