In order to examine the effect of the glycyl residues the stability of the α-helix, a series of blockpolypeptides containing ordered sequences of L-alanine and glycine residue were synthesized by heterogeneous polymerization of their N-carboxyanhydrides (NCA) in acetonitrile as p-phenylenediamine initiator with two functional groups. These molecular conformations were investigated by optical rotatory dispersion of dilute solution in dichloroacetic acid (DCA : helix solvent), and in trifluoroacetic acid (TFA : random coil solvent) and chloroform (CHCl₃ : helix solvent) mixtures. The results indicated that the glycyl residues reduced the stability of the α-helix and the order of the stability of the α-helix of these blockpolypeptides were found to be: (Ala)-(Gly)-(Ala)>(Ala)-(Gly)>(Ala)-(Gly)-(Ala)-(Gly)>(Gly)-(Ala)-(Gly)

Polypeptide 내에서 glycine의 위치와 수에 따른 helix 안정성에 미치는 영향을 연구하기 위하여 glycine과 L-alanine의 block copolypeptide를 이작용기성 일차아민인 p-페닐렌디아민을 개시제로 아세토니트릴중에서 NCA (N-carboxy-anhydride)법으로 합성한 glycine NCA와 L-alanine NCA를 불균일계로 중합하였다. Block copolypeptide 내에서의 helix 구조에 관한 glycine 잔기의 영향을 검토하기 위하여 helix 용매인 디클로로아세트산 및 random coil 용매인 트리풀루오로아세트산과 helix 용매인 클로로포름의 혼합용매중에서 선광분산을 측정하였다. Helix의 안정성은 (Ala)-(Gly)-(Ala), (Ala)-(Gly), (Ala)-(Gly)-(Ala)-(Gly) 및 (Gly)-(Ala)-(Gly)의 순서로 감소함을 알았으며, glycine 잔기가 L-alanine의 α-helix 형성에 방해작용을 한다는 것이 확인되었다.

Keywords: