THE NMR SOLUTION STRUCTURE OF A KUNITZ-TYPE PROTEINASE-INHIBITOR FROM THE SEA-ANEMONE STICHODACTYLA-HELIANTHUS
THE NMR SOLUTION STRUCTURE OF A KUNITZ-TYPE PROTEINASE-INHIBITOR FROM THE SEA-ANEMONE STICHODACTYLA-HELIANTHUS
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DOI：
10.1111/j.1432-1033.1993.tb17705.x
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发表时间：
1993-03-15
期刊：
影响因子：
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通讯作者：
WUTHRICH, K
中科院分区：
文献类型：
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作者：
ANTUCH, W;BERNDT, KD;WUTHRICH, K
从加勒比海海葵Stichodactyla helianthus中纯化的55-氨基酸Kunitz型蛋白酶抑制剂ShPI的溶液结构由NMR光谱确定。在pH 4.6和36 ° C下获得了几乎完整的序列特异性H-1-NMR分配，并确定了23对非对映异构取代基的立体特异性分配。在此基础上收集的666个距离上限约束和122个二面角约束的数据集被用作DIANA程序的结构计算的输入。在用程序OPAL进行能量最小化之后，用于表示溶液结构的20种DIANA构象异构体相对于平均结构的平均均方根偏差（RMSD）对于所有骨架原子N、Calpha和C '为61 μ m，并且对于残基2-53的所有重原子为106 μ m。这种高质量的ShPI溶液结构与牛胰蛋白酶抑制剂（BPTI）具有几乎相同的分子结构，尽管两种蛋白质之间的序列相似性仅为35%。交换率测量48的51个骨干酰胺质子表明，20个缓慢交换酰胺质子的位置相关以及涉及这些质子的能量最小化的溶液结构中的氢键。ShPI的溶液结构进行比较的四个同源蛋白质的三维结构也是可用的。
The solution structure of a 55-amino-acid Kunitz-type proteinase inhibitor, ShPI, purified from the Caribbean sea anemone Stichodactyla helianthus, was determined by NMR spectroscopy. Nearly complete sequence-specific H-1-NMR assignments were obtained at pH 4.6 and 36-degrees-C, and stereo-specific assignments were determined for 23 pairs of diastereotopic substituents. A data set of 666 upper distance limit constraints and 122 dihedral angle constraints collected on this basis was used as input for a structure calculation with the program DIANA. Following energy minimization with the program OPAL, the average root-mean-square diviation (RMSD) of the 20 DIANA conformers used to represent the solution structure relative to the mean structure is 61 pm for all backbone atoms N, Calpha and C', and 106 pm for all heavy atoms of residues 2-53. This hi-h-quality solution structure of ShPI has a nearly identical molecular architecture as the bovine pancreatic trypsin inhibitor (BPTI), despite a mere 35% of sequence similarity between the two proteins. Exchange rates measured for 48 out of the 51 backbone amide protons showed that the positions of 20 slowly exchanging amide protons correlate well with hydrogen bonds involving these protons in the energy-minimized solution structure. The solution structure of ShPI is compared to the four homologous proteins for which the three-dimensional structure is also available.