| Abstract: | A theoretical and experimental analysis of the preferred conformations of homo-peptides from Cα,α-dialkylated glycines revealed that these compounds are characterised by a marked structural versatility. Fully extended (C5-conformations). folded (of theβ-bend type), and 310-helical structures are adopted as a function of side-chain nature. Dimethylated and cyclic side chains favour folded and helical structures, whereas diethylated and longer acyclic side chains favour the fully extended structure. By means of conformational energy calculations the preferred screw sense of the helical structure of homo-peptides from a representative chiral acyclic residue is also anticipated. |
