Genetically Encoded Libraries of Constrained Peptides

Many therapeutic peptides can still be improved with respect to target specificity, target affinity, resistance to peptidases/proteases, physical stability and capacity to pass membranes required for oral delivery. Several modifications can improve the peptides' properties in particular those that impose (a) conformational constraint(s). The screening of constrained peptides and the identification of hits is a lot facilitated by the generation of genetically encoded libraries. Recent breakthrough bacterial, phage and yeast display screening systems of ribosomally-synthesized posttranslationally-constrained peptides, particularly those of lanthipeptides, are earning special attention. Here we provide a view of display systems of constrained, genetically encoded peptides and indicate prospects of constrained peptide-displaying phage and bacterial systems as such in vivo.