Peptide Isomerization is Suppressed at the Air–Water Interface
Peptide Isomerization is Suppressed at the Air–Water Interface
复制标题
肽异构化在空气与水界面处受到抑制
DOI：
10.1021/acs.jpclett.1c03837
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
Limmer, David T.
中科院分区：
文献类型：
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作者：
Singh, Aditya N.;Limmer, David T.
我们利用分子动力学模拟来研究丙氨酸二肽在空气-水界面异构化的热力学和动力学。从热力学角度来看，我们发现二肽对界面的亲和力。这种亲和力源于稳定的分子内相互作用，当二肽去溶剂化时，分子内相互作用变得不受保护。从动力学上讲，我们考虑丙氨酸二肽的 αL 和 β 构象之间的转变速率，并使用最近扩展的转变路径采样 TPS+U 将其评估为距界面距离的连续函数。吉布斯分界面处的异构化速率相对于本体被抑制了 3 倍。对过渡态整体的检查阐明了溶剂自由度在沿着异构化反应途径介导有利的分子内相互作用中的作用。在空气-水界面附近，水介导这些分子内相互作用的效果较差。
We use molecular dynamics simulations to study the thermodynamics and kinetics of alanine dipeptide isomerization at the air–water interface. Thermodynamically, we find an affinity of the dipeptide to the interface. This affinity arises from stabilizing intramolecular interactions that become unshielded as the dipeptide is desolvated. Kinetically, we consider the rate of transitions between the αLand β conformations of alanine dipeptide and evaluate it as a continuous function of the distance from the interface using a recent extension of transition path sampling, TPS+U. The rate of isomerization at the Gibbs dividing surface is suppressed relative to the bulk by a factor of 3. Examination of the ensemble of transition states elucidates the role of solvent degrees of freedom in mediating favorable intramolecular interactions along the reaction pathway of isomerization. Near the air–water interface, water is less effective at mediating these intramolecular interactions.