Molecular Biophysics Unit, Indian Institute of Science, Bangalore-560012, India.
J Pept Sci. 2010 Aug;16(8):430-6. doi: 10.1002/psc.1259.
The solution conformation of a designed tetradecapeptide Boc-Val-Ala-Leu-Dpg-Val-Ala-Leu-Val-Ala-Leu-Dpg-Val-Ala-Leu-OMe (Dpg-14) containing two di-n-propyl glycine (Dpg) residues has been investigated by (1)H NMR and circular dichroism in organic solvents. The peptide aggregates formed at a concentration of 3 mM in the apolar solvent CDCl(3) were broken by the addition of 12% v/v of the more polar solvent DMSO-d(6). Successive N(i)H <--> N(i+1)H NOEs observed over the entire length of the sequence in this solvent mixture together with the observation of several characteristic medium-range NOEs support a major population of continuous helical conformations for Dpg-14. Majority of the observed coupling constants (3)JNHC(alpha)H) also support phi values in the helical conformation. Circular dichroism spectra recorded in methanol and propan-2-ol give further support in favor of helical conformation for Dpg-14 and the stability of the helix at higher temperature.
已通过（1）H NMR 和圆二色性在有机溶剂中研究了含有两个二正丙基甘氨酸（Dpg）残基的设计的十四肽 Boc-Val-Ala-Leu-Dpg-Val-Ala-Leu-Val-Ala-Leu-Dpg-Val-Ala-Leu-OME（Dpg-14）的溶液构象。在非极性溶剂 CDCl3 中浓度为 3mM 时形成的肽聚集体通过添加 12％v/v 的更极性溶剂 DMSO-d6 被打破。在该溶剂混合物中，在整个序列长度上观察到连续的 N（i）H <--> N（i+1）H NOE，以及几个特征的中程 NOE 的观察，支持 Dpg-14 主要存在连续螺旋构象。大多数观察到的耦合常数（3）JNHC（alpha）H）也支持螺旋构象中的 phi 值。在甲醇和异丙醇中记录的圆二色谱谱进一步支持 Dpg-14 为螺旋构象以及在较高温度下螺旋的稳定性。
