NMR studies of molecular conformations in alpha-cyclodextrin.
NMR studies of molecular conformations in alpha-cyclodextrin.
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α-环糊精分子构象的核磁共振研究。
DOI：
10.1021/jp802681z
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
A. Maliniak
中科院分区：
文献类型：
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作者：
Johan Thaning;Baltzar Stevensson;Jennie Ostervall;K. Naidoo;G. Widmalm;A. Maliniak
提出了一种新的核磁共振参数分析方法。实验数据集包括标量耦合、NOE和残余偶极耦合。该方法，其目的是在构象分布函数的建设，适用于α-环糊精在各向同性溶液和溶解在稀液晶。试图用平均分子构象分析实验数据，导致了不可接受的误差。我们的方法依赖于最大熵方法（ME），它给出了最平坦的可能的分布，与实验数据一致。实验和计算的NMR参数之间的非常好的协议进行了观察。事实上，需要两个构象状态，以获得一个令人满意的协议之间的计算和实验数据。此外，与Langevin动力学的计算机模拟得到了很好的一致性。
A new approach for analysis of NMR parameters is proposed. The experimental data set includes scalar couplings, NOEs, and residual dipolar couplings. The method, which aims at construction of the conformational distribution function, is applied to alpha-cyclodextrin in isotropic solution and dissolved in a dilute liquid crystal. An attempt to analyze the experimental data using an average molecular conformation resulted in unacceptable errors. Our approach rests on the maximum entropy method (ME), which gives the flattest possible distribution, consistent with the experimental data. Very good agreement between experimental and calculated NMR parameters was observed. In fact, two conformational states were required in order to obtain a satisfactory agreement between calculated and experimental data. In addition, good agreement with Langevin dynamics computer simulations was obtained.