Effect of Transition-Metal Ions on the Conformation of Encephalin Investigated by Hydrogen/Deuterium Exchange and Theoretical Calculations
Effect of Transition-Metal Ions on the Conformation of Encephalin Investigated by Hydrogen/Deuterium Exchange and Theoretical Calculations
复制标题
氢/氘交换及理论计算研究过渡金属离子对脑磷脂构象的影响
DOI：
10.1021/acs.jpcb.9b09919
复制
发表时间：
2020-01-09
影响因子：
3.3
通讯作者：
Ding，Chuan-Fan
中科院分区：
文献类型：
--
作者：
Wu，Fangling;Huang，Yandong;Ding，Chuan-Fan
本文研究了二价过渡金属离子[G ~（2+）= Mn ~（2+）（d_5），Fe ~（2+）（d_6），Co ~（2+）（d_7），Ni ~（2+）（d_8），Cu ~（2+）（d_9），或Zn ~（2+）（d10）]对亮氨酸脑磷脂（LE）和甲硫氨酸脑磷脂（ME）构象的影响和分子水平上的理论计算。HDX-MS显示了1：1化学计量比的[LE/ME + G-H]+的单价络合物，并观察到不同的HDX反应性遵循Fe 2 +<Co 2 +<Ni 2 +<Mn 2 +<Cu 2 +<Zn 2+的趋势，并且[ME + Mn/Cu/Zn-H]+> [LE + Mn/Cu/Zn-H]+，而[LE + Fe/Co/Ni-H]+> [ME + Fe/Co/Ni-H]+。我们交叉相关的碰撞诱导解离能的复合物与HDX的结果，发现越稳定的复合物，它是难以为它进行HDX。此外，我们使用理论计算优化的配合物的有利构象，发现相同的相互作用结构的G2+与LE/ME的五个羰基氧具有不同的键长的协调。最后，我们计算了优化的复合物的质子亲和力（PA）值，以解释HDX观察结果，PA值越高，复合物越难进行HDX。总之，实验和理论计算都表明，六种金属离子对LE/ME构象有不同的影响，G2+3d轨道的低能稳定性对应于LE/ME构象的更显着的影响。此外，Mn ~（2+）和Zn ~（2+）半填充轨道对应的离子酸硬度对配位效应也有很大贡献，Fe ~（2+）/Co ~（2+）/Ni ~（2+）对LE的构象效应大于对ME的构象效应，而Mn ~（2+）/Cu ~（2+）/Zn ~（2+）对ME的构象效应大于对LE的构象效应.
We have studied the effects of different 3d orbitals in divalent transition-metal ions [G2+= Mn2+(d5), Fe2+(d6), Co2+(d7), Ni2+(d8), Cu2+(d9), or Zn2+(d10)] on the conformations of leucine encephalin (LE) and methionine encephalin (ME) in the gas phase using hydrogen/deuterium exchange mass spectrometry (HDX-MS) and theoretical calculations at the molecular level. The HDX-MS reveals a 1:1 stoichiometric monovalent complex of [LE/ME + G – H]+and observed that the different HDX reactivities follow the trend Fe2+< Co2+< Ni2+< Mn2+< Cu2+≈ Zn2+and that [ME + Mn/Cu/Zn – H]+> [LE + Mn/Cu/Zn – H]+, while [LE + Fe/Co/Ni – H]+> [ME + Fe/Co/Ni – H]+. We cross-correlated the collision-induced dissociation energies of the complexes with the HDX results and found that the more stable the complex, the harder it is for it to undergo HDX. Furthermore, we used theoretical calculations to optimize the favorable conformations of the complexes and found the same interaction structure of G2+coordination with the five carbonyl oxygens of LE/ME that have different bond lengths. Finally, we calculated the proton affinity (PA) values of the optimized complexes in order to interpret the HDX observations that the higher the PA values, the more difficult it is for the complex to undergo HDX. Overall, both the experiments and the theoretical calculations show that the six metal ions have different effects on the LE/ME conformation, with the low-energy stability of the G2+3d orbitals corresponding to more dramatic effects on the LE/ME conformation. In addition, the hardness of the ionic acid corresponding to the fully filled Mn2+and half-filled Zn2+orbitals also contributes strongly to the coordination effect; the conformation effect of Fe2+/Co2+/Ni2+on LE is greater than that on ME, whereas the conformation effect of Mn2+/Cu2+/Zn2+on ME is greater than that on LE.