Three-dimensional structure of gurmarin, a sweet taste-suppressing polypeptide
Three-dimensional structure of gurmarin, a sweet taste-suppressing polypeptide
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甜味抑制多肽古尔马林的三维结构
DOI：
10.1007/bf00211756
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发表时间：
1995
影响因子：
2.7
通讯作者：
K. Akasaka
中科院分区：
文献类型：
--
作者：
Katsuaki Arai;R. Ishima;Soichi Morikawa;A. Miyasaka;T. Imoto;S. Yoshimura;S. Aimoto;K. Akasaka
摘要通过 600 MHz 的二维质子核磁共振波谱研究了古尔马林的溶液结构。 Gumarin 是最近在印度原产的匙羹藤 (Gymnema sylvestre) 中发现的一种 35 个氨基酸残基的多肽，可选择性抑制大鼠对甜味刺激的神经反应。序列特异性质子。三维溶液结构是根据来自NOE的135个质子间距离约束、三个氢键的6个距离约束和来自耦合常数的16个二面角约束通过模拟退火计算确定的。总共 10 个结构折叠成具有三链反平行 β 折叠的明确结构。主链原子（N、Cα、C）的任意两个结构之间的平均 rmsd 值为 1.65±0.39 Å，所有重原子的平均 rmsd 值为 2.95±0.27 Å。三个二硫键的位置无法通过化学方法确定，根据NMR距离限制估计为Cys3-Cys18、Cys10-Cys23和Cys17-Cys33。结果发现，古马素中的二硫键模式与 ω-芋螺毒素和苦瓜胰蛋白酶抑制剂-II 中的二硫键模式类似，并且折叠拓扑与 ω-芋螺毒素中的相同。
SummaryThe solution structure of gurmarin was studied by two-dimensional proton NMR spectroscopy at 600 MHz. Gurmarin, a 35-amino acid residue polypeptide recently discovered in an Indian-originated tree Gymnema sylvestre, selectively suppresses the neural responses of rat to sweet taste stimuli. Sequence-specific protons. The three-dimensional solution structure was determined by simulated-annealing calculations on the basis of 135 interproton distance constraints derived from NOEs, six distance constraints for three hydrogen bonds and 16 dihedral angle constraints derived from coupling constants. A total of 10 structures folded into a well-defined structure with a triple-stranded antiparallel β-sheet. The average rmsd values between any two structures were 1.65±0.39 Å for the backbone atoms (N, Cα, C) and 2.95±0.27 Å for all heavy atoms. The positions of the three disulfide bridges, which could not be deterermined chemically, were estimated to be Cys3–Cys18, Cys10–Cys23 and Cys17–Cys33 on the basis of the NMR distance constraints. This disulfide bridge pattern in gurmarin turned out to be analogous to that in ω-conotoxin and Momordica charantia trypsin inhibitor-II, and the topology of folding was the same as that in ω-conotoxin.