摘要
Conformations and reaction energetics are important for understanding the interactions be- tween biomolecules and metal ions. In this work, we report a systematic ab initio study on the conformations and metal ion affinities of glutamine （Gln） binding with alkali and alkaline earth metal ions. An efficient and reliable method of searching low energy conformations of metalated Gln is proposed and applied to the complexes of Gln.Gln.M^＋/＋＋（M＋/＋＋=Li^＋、Na^＋、K^＋、Rb^＋、Cs^＋、Be^＋＋、Mg^＋＋、Ca^＋＋、Sr^＋＋ and Ba^＋＋）.. In addition to all conformers known in literatures, many new important conformations are located, demonstrating the power of the new method and the necessity of the conformational search performed here. The metal coordination modes, relative energies, dipole moments, and equilibrium distributions of all important conformations of Gln.M^＋/＋＋ are calculated by the methods of B3LYP, BHandHLYP, and MP2. IR spectra and metalation enthalpies and free energies are also presented and compared with the available experiments. The results form an extensive database for systematic examination of the metalation properties of Gln.
基金
ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.11074233 and No.11374272） and the Specialized Research Fund for the Doctoral Program of Higher Education （No.20113402110038 and No.20123402110064）
