Department of Chemistry , Stanford University , Stanford , California 94035 , United States.
Stanford Synchrotron Radiation Lightsource, SLAC , Stanford University , Menlo Park , California 94025 , United States.
Biochemistry. 2019 Aug 27;58(34):3585-3591. doi: 10.1021/acs.biochem.9b00542. Epub 2019 Aug 14.
NikR is a nickel-responsive metalloregulator protein that controls the level of Ni ions in living cells. Previous studies have shown that NikR can bind a series of first-row transition metal ions but binds to DNA with high affinity only as a Ni complex. To understand this metal selectivity, S K-edge X-ray absorption spectroscopy of NikR bound to different metal ions was used to evaluate the different electronic structures. The experimental results are coupled with density functional theory calculations on relevant models. This study shows that both the of the metal ion and the donor nature of the ligands determine the electronic structure of the metal site. This impacts the geometric structure of the metal site and thus the conformation of the protein. This contribution of electronic structure to geometric structure can be extended to other metal selective metalloregulators.
NikR 是一种镍响应型金属调控蛋白，可控制活细胞中镍离子的水平。先前的研究表明，NikR 可以结合一系列第一过渡系金属离子，但仅作为 Ni 络合物与 DNA 具有高亲和力。为了理解这种金属选择性，使用 S K 边 X 射线吸收光谱法研究了与不同金属离子结合的 NikR，以评估不同的电子结构。实验结果与相关模型的密度泛函理论计算相结合。本研究表明，金属离子的 和配体的供电子性质共同决定了金属位点的电子结构。这会影响金属位点的几何结构，从而影响蛋白质的构象。这种电子结构对几何结构的影响可以扩展到其他金属选择性金属调控蛋白。
