Meyer J P, Pelton J T, Hoflack J, Saudek V
Merrell Dow Research Institute, Strasbourg, France.
Biopolymers. 1991 Feb 5;31(2):233-41. doi: 10.1002/bip.360310210.
Salmon calcitonin, a 32-residue peptide with a 1-7 disulfide bridge, was synthesized by standard solid-phase techniques, and studied by CD and two-dimensional NMR experiments. The peptide was dissolved in pure trifluoroethanol (TFE) and in aqueous solutions containing various amounts of TFE. CD studies in pure TFE indicated the presence of an alpha-helical structure comprising 40% of the constituent amino acids. This was fully confirmed by nmr. A detailed analysis was performed with the peptide in a 9 : 1 deuterated TFE/H2O mixture. A total of 365 nuclear Overhauser enhancements (154 intraresidual, 112 sequential and 99 long range) were complied from the nuclear Overhauser enhancement spectroscopy spectra and used in the distance geometry calculations. The core of the peptide between residues 8 and 22 assumes an alpha-helix like structure. The Cys 1-Cys 7 ring is well defined and in close association with the helix, while the C-terminal decapeptide folds back toward the core, forming a loose loop.
鲑鱼降钙素是一种含有1-7二硫键的32个残基的肽，采用标准固相技术合成，并通过圆二色光谱（CD）和二维核磁共振实验进行研究。该肽溶解于纯三氟乙醇（TFE）以及含有不同量TFE的水溶液中。在纯TFE中的CD研究表明存在一种α-螺旋结构，其包含40%的组成氨基酸。核磁共振完全证实了这一点。在9:1的氘代TFE/H₂O混合物中对该肽进行了详细分析。从核Overhauser增强光谱（NOESY）谱中总共整理出365个核Overhauser增强效应（154个残基内、112个序列间和99个长程），并用于距离几何计算。8至22位残基之间的肽段核心呈现出类似α-螺旋的结构。Cys 1-Cys 7环结构明确，与螺旋紧密相连，而C端十肽向核心折叠回去，形成一个松散的环。
