Enter a new post-translational modification: D-amino acids in gene-encoded peptides.

The post-translational processing of peptides plays a key role in conferring biological activity on those peptides. Recently, ribosomally made peptides that contain D-amino acids at specific positions have been discovered in microorganisms as well as in vertebrates and invertebrates. This points to yet another strategy of circumventing stereochemical limitations imposed by the genetic code and conveying biological activity to otherwise inert molecules.