Department of Chemistry, Boston University, Boston, MA 02215, USA.
Phys Chem Chem Phys. 2021 Aug 12;23(31):16506-16515. doi: 10.1039/d0cp06632j.
Redox reactions are crucial to biological processes that protect organisms against oxidative stress. Metalloenzymes, such as peroxidases which reduce excess reactive oxygen species into water, play a key role in detoxification mechanisms. Here we present the results of a polarizable QM/MM study of the reduction potential of the electron transfer heme in the cytochrome c peroxidase of Nitrosomonas europaea. We have found that environment polarization does not substantially affect the computed value of the redox potential. Particular attention has been given to analyzing the role of electrostatic interactions within the protein environment and the solvent on tuning the redox potential of the heme co-factor. We have found that the electrostatic interactions predominantly explain the fluctuations of the vertical ionization/attachment energies of the heme for the sampled configurations, and that the long range electrostatic interactions (up to 40 Å) contribute substantially to the absolute values of the vertical energy gaps.
氧化还原反应对保护生物免受氧化应激的生物过程至关重要。金属酶，如将过量的活性氧物种还原为水的过氧化物酶，在解毒机制中起着关键作用。在这里，我们展示了对来自欧洲硝化单胞菌的细胞色素 c 过氧化物酶中的电子转移血红素还原电势进行极化量子力学/分子力学研究的结果。我们发现环境极化不会显著影响计算出的氧化还原电势值。特别关注分析蛋白质环境和溶剂中的静电相互作用在调节血红素辅因子氧化还原电势方面的作用。我们发现，静电相互作用主要解释了取样构象中血红素的垂直电离/附加能的波动，并且长程静电相互作用（高达 40 Å）对垂直能隙的绝对值有很大贡献。
