Studies Toward the Rational Design of Ion Binding Proteins

无机化学、生物无机化学和金属有机化学项目的这一奖项由仪器多学科活动数学和物理科学办公室贡献，用于支持俄亥俄州立大学化学系James Cowan教授的实验室工作。这项研究将检测和比较E.Coli核糖核酸酶H、核酸外切酶II和其他蛋白质的镁(II)结合结构域。由于镁(II)必须从环境或细胞介质中招募，而且结合亲和力通常不高，因此影响水解所需的这种金属辅因子的化学计量比通常没有很好的定义。虽然金属结合结构域在金属的电荷密度和配位方面表现出很大的变化，但它们具有类似的结合亲和力。研究将集中在镁与天然酶和突变酶结合的量热和核磁共振研究。这些结果将为合理设计具有新型阳离子或阴离子结合化学的蛋白质奠定基础。本研究对镁离子在重要水解酶中的内外配位、金属离子电荷密度和溶剂化、结合亲和力等因素的相对重要性进行了系统的研究。这些研究不仅应该提高我们对镁在蛋白质中作用的理解，而且结果也应该被证明对蛋白质中离子结合部位的合理设计具有非常重要的意义。

This award in the Inorganic, Bioinorganic and Organometallic Chemistry Program with a contribution from the Mathematics and Physical Sciences Office of Multidisciplinary Activities for instrumentation supports work in the laboratory of Professor James Cowan in the Department of Chemistry at Ohio State University. The research will examine and compare the Mg(II) binding domains of E.Coli RNase H, exonuclease II and other proteins. Since Mg(II) must be recruited from the environment or cellular medium and binding affinities are often not high, the stoichiometry of this metal cofactor required to effect hydrolysis is often not well defined. While the metal binding domains show considerable variation in charge density and coordination for the metal, they have comparable binding affinities. Studies will focus on calorimetric and NMR investigations of Mg binding to native and mutant enzymes. The results will form the basis for the rational design of proteins with novel cation or anion binding chemistry. This research involves a systematic investigation to define the relative importance of Mg(II) inner and outer-sphere coordination, metal ion charge density and solvation, binding affinity and other factors in the use of Mg(II) in important hydrolytic enzymes. Not only should these studies improve our understanding of the role of magnesium in proteins, but results should also prove highly significant in the rational design of ion binding sites in proteins.