TRYPTOPHAN-47 ROTATIONAL ISOMERIZATION IN VARIANT-3 SCORPION NEUROTOXIN - A COMBINATION THERMODYNAMIC PERTURBATION AND UMBRELLA SAMPLING STUDY
TRYPTOPHAN-47 ROTATIONAL ISOMERIZATION IN VARIANT-3 SCORPION NEUROTOXIN - A COMBINATION THERMODYNAMIC PERTURBATION AND UMBRELLA SAMPLING STUDY
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DOI：
10.1016/s0006-3495(90)82645-x
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发表时间：
1990-06-01
影响因子：
3.4
通讯作者：
PRENDERGAST, FG
中科院分区：
文献类型：
--
作者：
HAYDOCK, C;SHARP, JC;PRENDERGAST, FG
结合热力学微扰和伞形采样研究预测两个自由能威尔斯井的旋转异构化的变体-3蝎神经毒素色氨酸-47吲哚侧链。一个阱具有处于晶体学取向的吲哚侧链;另一个阱具有旋转约220度的吲哚以形成具有3 ± 1的相对自由能的新构象。2千卡/摩尔。从晶体学阱起，活化势垒为8.5千卡/摩尔，过渡态理论由此预测逃逸速率为2 × 10 - 4。色氨酸-47侧链位移与异构化反应坐标的相关性可达20 ps。讨论了实验验证的有利条件。
A combination thermodynamic perturbation and umbrella sampling study predicts two free energy wells for the rotational isomerization of the variant-3 scorpion neurotoxin tryptophan-47 indole side chain. One well has the indole side chain in the crystallographic orientation; the other has the indole rotated .apprx.220 degrees to form a new conformation with a relative free energy of 3 .+-. 2 kcal/mol. The activation barrier is 8.5 kcal/mol from the crystallographic well, from which transition state theory predicts a rate of escape of 2 .times. 105 s-1.Correlations in the displacement of side chains neighboring tryptophan-47 and the isomerization reaction coordinate last up to 20 ps. Favorable conditions of experimental verification are discussed.