Modeling of the structure and functional mechanisms of v

在过去的一年里，我们开发了Shaker、KvAP、hERG和NaChBac通道在静止、开放和许多过渡构象下的跨膜和细胞外片段的结构模型。这些通道嵌入在脂质双分子层的分子动力学模拟进行了评估和完善的模型。模型受新近获得的实验数据的约束；例如，Kv1.2通道的晶体结构，KvAP通道的电子顺磁共振（EPR）研究，蝎子BeKM1毒素与hERG通道结合的热力学循环诱变研究，以及Ca2+通道孔的半胱氨酸扫描诱变（SCAM）研究。我们已经证明，我们在1986年首次提出的S4电压传感器段的电压依赖运动的“螺旋”模型几乎与所有实验结果和能量标准一致，包括使用分子动力学模拟的分析。NaChBac通道是一种原核Na+通道，与K+、Ca2+和Na+通道相似。我们是第一个在原核生物序列数据库中发现这个序列的小组。从那时起，人们对它进行了表达，并对它的性质进行了昂贵的研究。人们正在努力解开它的晶体结构。我们开发了NaChBac模型，主要是将其作为模拟更复杂的真核Ca2+和Na+通道的垫脚石。我们使用NaChBac模型作为模板结构来开发人类和真菌Ca2+通道的同源模型。我们正在与实验学家合作测试这些模型，并使用它们来分析Ca2+通道阻滞剂的分子药理学。

During the last year, we have developed structural models of the transmembrane and extracellular segments of Shaker, KvAP, hERG, and NaChBac channels in resting, open, and numerous transition conformations. Molecular dynamic simulations of these channels embedded in a lipid bilayer were performed to evaluate and refine the models. The models were constrained by recently obtained experimental data; e.g., the crystal structure of the Kv1.2 channel, electron paramagnetic resonance (EPR) studies of KvAP channels, thermodynamic cyclic mutagenesis studies of the binding of BeKM1 toxin from scorpions to the hERG channel, and cysteine scanning mutagenesis (SCAM) studies of Ca2+ channel pores. We have demonstrated that the 'helical screw' model for the voltage-dependent movement of the S4 voltage-sensor segment that we proposed first in 1986, is consistent with virtually all experimental results and with energetic criteria, including analyses using molecular dynamic simulations. The NaChBac channel is a prokaryotic Na+ channel that has similarities to K+, Ca2+, and Na+ channels. We were the first group to identify this sequence in the prokaryotic sequence data base. Since then, it has been expressed and its properties have been studied expensively. Efforts are underway to solve its crystal structure. We developed models of NaChBac, primarily to use it as a stepping stone to model more complex eukaryotic Ca2+ and Na+ channels. We have used the NaChBac models as template structures to develop homology models of human and fungal Ca2+ channels. We are collaborating with experimentalists to test these models and to use them to analyze the molecular pharmacology of Ca2+ channel blockers.