An empirical approach based on the previously developed zinc AMBER force field (ZAFF) is proposed for the determination of the parameters for bonds and angles involving zinc. We call it the extended ZAFF (EZAFF) model because the original ZAFF model was only formulated for four-coordinated systems, while EZAFF additionally can tackle five- and six-coordinated systems. Tests were carried out for six metalloproteins and six organometallic compounds with different coordination spheres. Results validated the reliability of the current model to handle a variety of zinc containing complexes. Meanwhile, benchmark calculations were performed to assess the performance of three bonded molecular mechanics models (EZAFF, Seminario, and Z-matrix models), four nonbonded parameter sets (the HFE, IOD, CM, and 12-6-4 models), and four semiempirical quantum mechanical methods (AM1, PM3, PM6, and SCC-DFTB methods) for simulating zinc containing systems. The obtained results indicate that, even with their increased computational cost, the semiempirical quantum methods only offered slightly better accuracy for the computation of relative energies and only afforded similar molecular geometries, when compared to the investigated molecular mechanics models.

中文翻译：

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扩展锌琥珀色力场（EZAFF）

提出了一种基于先前开发的锌AMBER力场（ZAFF）的经验方法，用于确定涉及锌的键和角的参数。我们将其称为扩展ZAFF（EZAFF）模型，因为原始的ZAFF模型仅适用于四坐标系统，而EZAFF可以处理五坐标和六坐标系统。对六种金属蛋白和六种具有不同配位域的有机金属化合物进行了测试。结果验证了当前模型处理各种含锌配合物的可靠性。同时，执行基准计算来评估三种键合分子力学模型（EZAFF，Seminario和Z-matrix模型），四个非键合参数集（HFE，IOD，CM和12-6-4模型）的性能，以及四种用于模拟含锌系统的半经验量子力学方法（AM1，PM3，PM6和SCC-DFTB方法）。所获得的结果表明，与所研究的分子力学模型相比，即使增加了计算成本，半经验量子方法也只能为相对能量的计算提供更高的精度，并且只能提供相似的分子几何形状。