EXTENDING THE PROLINE EFFECT - PSI-PRO FOR TAILORING CIS-TRANS ISOMERIZATION

Pseudo-Prolines (Psi Pro) consist of (4S)-oxazolidine- and (4R)-thiazo lidine-carboxylic acids derived from amino acids Ser, Thr and Cys. The y represent new branched proline analogues in which variation of the s ubstituents (R-1, R-2, R-3) results in different physicochemical and c onformational properties. We summarise here the relevant chemical and structural aspects of such super-prolines intended to constrain and co ntrol the peptide backbone in beta-turn motifs or to alter the imide c is-trans ratio.