Mikkelsen K V, Skov L K, Nar H, Farver O
H. C. Orsted Institute, University of Copenhagen, Denmark.
Proc Natl Acad Sci U S A. 1993 Jun 15;90(12):5443-5. doi: 10.1073/pnas.90.12.5443.
Electronic coupling between the copper atoms in an azurin dimer has been calculated in this conformationally well-defined system by using many-electronic wave functions. When one of the two water molecules forming intermolecular hydrogen bonds between the copper-ligating His-117 of the two azurins is removed, the calculated coupling element is reduced from 2.5 x 10(-6) to 1.1 x 10(-7) eV (1 eV = 1.602 x 10(-19) J). Also, the effects of the relative orientations of the two water molecules have been analyzed. The results show that water molecules may play an important role as switches for biological electron transfer. The rate of electron self-exchange between two azurins has been calculated, and the result is in very good agreement with the rate found experimentally.
在这个构象明确的体系中，通过使用多电子波函数计算了天青蛋白二聚体中铜原子之间的电子耦合。当形成两个天青蛋白之间分子间氢键的两个水分子中的一个被移除时，计算得到的耦合元件从2.5×10⁻⁶降低到1.1×10⁻⁷电子伏特（1电子伏特 = 1.602×10⁻¹⁹焦耳）。此外，还分析了两个水分子相对取向的影响。结果表明，水分子可能作为生物电子转移的开关发挥重要作用。计算了两个天青蛋白之间的电子自交换速率，结果与实验发现的速率非常吻合。
