Effective De novo designing of proteins is a great challenge and a cri
tical test of our knowledge of protein structure. The main problem is
the attainment of a protein with a defined fold for its specific funct
ion. This paper reports the synthesis and characterization of a series
of helix - turn - helix (h-t-h) peptides with stable secondary and te
rtiary structures. In the order to optimize the stability of the anti-
parallel coiled-coil structure of alpha helical hairpin peptides, all
peptides with the same interacting helical regions but different numbe
r and sequences of residues in the turn region was examined The turn r
egion was incorporated between g and e(2) of leucine zipper heptad CD
measurements showed that a four residue turn region was the best of st
abilizing coiled coil structure in these peptides. The four residue tu
rn sequence selected from h-t-h motifs of DNA binding proteins showed
the highest helix stabilization in a short peptide of twenty nine amin
o acid residues.