中文摘要：

通过密度泛函理论计算了天然NiSOD氧化态（ox）／NiSOD还原态（red）的活性中心的电子结构．采用INDO／S方法计算了电子光谱，并与实验值进行了比较．从前线分子轨道及自然键轨道布居等方面揭示了S原子在催化超氧阴离子的活性中的作用，以及NiSOD具有较高结构稳定性的原因．结果表明：NiSODox／NiSODred分别以低自旋态为最稳定状态，计算值与实验结果一致．

英文摘要：

The electronic structures of the NiSOD active site in its oxidized, reduced states were explored by density functional theory. The results show that the states with low spins of the both NiSOD active site are the most stable, which agree well with the experiment. The electronic spectrum was calculated by INDO/S method. The frontier molecular orbitals and natural bond orbital population were discussed, for revealing the reason that the active forms is stable,and the S atom play a key role in susceptible to accept the electronic on superoxide anion radical to accomplish the physiological function.