摘要:
Designing cyclic tetrapeptides (CTPs), which fold into desired structures, is often a challenging task. While it is difficult to synthesize them, they are also prone to adopt multiple conformations. In this paper we report the synthesis and conformational studies of CTP mimics, having nonconstrained alpha(3)beta motif, that exhibit stable beta- and gamma-turn structures. We also demonstrate the transformation of beta-turn to gamma-turn structure in similar CTPs by inverting the chirality of beta carbon in C-linked-carbo-beta(3)-amino acid (Caa) from R to S.