On the Stability of a Single-Turn α-Helix: The Single versus Multiconformation Problem
On the Stability of a Single-Turn α-Helix: The Single versus Multiconformation Problem
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关于单匝 α 螺旋的稳定性：单构象与多构象问题
DOI：
10.1021/ja0278279
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
M. Kelso
中科院分区：
文献类型：
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作者：
J. Snyder;and Ami S. Lakdawala;M. Kelso
五肽ac - haaa - nh2通过PdII环化其咪唑得到[Pd(en)（肽）]2+，最近通过二维核磁共振和模拟退火在溶液中作为单一α-螺旋构象进行了评估。在目前的工作中，我们通过开发琥珀*的Pd2+参数，对[Pd(en)（肽）]2+进行广泛的构象搜索，并将平均NMR数据反卷积为8个快速平衡的构象，其占比从2到55%不等，从而质疑了这一假设。后者都不对应于α-螺旋，尽管3%的形式具有相关的结构。作为从单一构象角度解释平均核磁共振谱的关键组成部分，我们建议使用允许构象反褶积的方法来测试这一假设。
The pentapeptide Ac-HAAAH-NH2, cyclized through its imidazoles by PdII to give [Pd(en)(peptide)]2+, has recently been evaluated by 2-D NMR and simulated annealing as a single α-helix conformation in solution. In the present work, we have questioned this assumption by developing Pd2+ parameters for AMBER*, performing an extensive conformational search for the [Pd(en)(peptide)]2+, and deconvoluting the averaged NMR data into eight rapidly equilibrating conformations with populations ranging from 2 to 55%. None of the latter correspond to the α-helix, although a 3% form possesses a related structure. As a critical component of interpreting an averaged NMR spectrum in terms of a single conformation, we advise testing this assumption with a method that permits conformational deconvolution.