Energies and physicochemical properties of cation-π interactions in biological structures
Energies and physicochemical properties of cation-π interactions in biological structures
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DOI：
10.1016/j.jmgm.2011.12.002
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发表时间：
2012-04-01
影响因子：
2.9
通讯作者：
Huang, Ri-Bo
中科院分区：
文献类型：
--
作者：
Du, Qi-Shi;Meng, Jian-Zong;Huang, Ri-Bo
阳离子-π相互作用经常发生在蛋白质内或蛋白质之间，这是由于20种天然氨基酸中的6种（Phe、Tyr、Trp、Arg、Lys和His）可能通过这些相互作用与金属阳离子相互作用。本研究利用量子化学计算和分子轨道理论研究了生物结构中阳离子π相互作用的能量和性质。H+和Li+的阳离子-π相互作用分别类似于氢键和锂键，其中小的裸露阳离子H+和Li+深埋在芳香族分子的π电子密度内，形成稳定的阳离子rr键，其比其他碱金属阳离子的阳离子-π相互作用强得多。原子质量大于Li+的金属阳离子的阳离子-π相互作用主要来自于由金属阳离子的空价原子轨道（AO）和芳香族分子的π-MO组成的配位键，尽管静电相互作用也可能有助于阳离子-π相互作用。阳离子-π相互作用的结合强度由金属阳离子中AO的电荷和类型决定。阳离子rr相互作用能与距离和取向有关;能量随着距离（r）和取向角（θ）而降低。在溶液中，阳离子rr的能量随着溶剂的介电常数（ε）的增加而减小;然而，溶剂化对H+-pi和H3 O +-pi相互作用的影响小于与其他阳离子的相互作用。从这项研究的结论提供了有用的理论见解的性质，阳离子-π相互作用，并可能有助于更好的力场参数的发展，用于描述分子动力学的阳离子-π相互作用内和蛋白质之间。(C)2011 Elsevier Inc. All rights reserved.
The cation-pi interactions occur frequently within or between proteins due to six (Phe, Tyr, Trp, Arg, Lys, and His) of the twenty natural amino acids potentially interacting with metallic cations via these interactions. In this study, quantum chemical calculations and molecular orbital (MO) theory are used to study the energies and properties of cation pi interactions in biological structures. The cation-pi interactions of H+ and Li+ are similar to hydrogen bonds and lithium bonds, respectively, in which the small, naked cations H+ and Li+ are buried deep within the pi-electron density of aromatic molecules, forming stable cation rr bonds that are much stronger than the cation-pi interactions of other alkali metal cations. The cation-ir interactions of metallic cations with atomic masses greater than that of Li+ arise mainly from the coordinate bond comprising empty valence atomic orbitals (AOs) of metallic cations and pi-MOs of aromatic molecules, though electrostatic interactions may also contribute to the cation-pi interaction. The binding strength of cation-pi interactions is determined by the charge and types of AOs in the metallic cations. Cation rr interaction energies are distance- and orientation-dependent; energies decrease with the distance (r) and the orientation angle (theta). In solution, the cation rr energies decrease with the increase of the dielectric constant (epsilon) of the solvent; however, solvation has less influence on the H+-pi and H3O+-pi interactions than on interactions with other cations. The conclusions from this study provide useful theoretical insights into the nature of cation-pi interactions and may contribute to the development of better force field parameters for describing the molecular dynamics of cation-pi interactions within and between proteins. (C) 2011 Elsevier Inc. All rights reserved.