CAA: Structural Studies on Multicopper Proteins

本项目的目标是通过X射线衍射技术确定两种多铜蛋白质的晶体结构。第一种蛋白质是来自链霉菌的多铜氧化酶吩嗪酮合酶（PHS），催化放线菌素D生物合成的倒数第二步。 第二种蛋白质是一种来自氨氧化细菌亚硝化单胞菌的小金属结合蛋白（SmbP），能够结合多达6个Cu（II）离子，并在这种金属存在下显示出不寻常的热稳定性。PHS和SmbP的三维结构尚不清楚，它们的结构将被确定，为对这些蛋白质进行的生物化学研究提供结构支持。 本研究的长期目标是了解金属蛋白中蛋白质的结构、功能、稳定性和寡聚体组装之间的关系。 多铜氧化酶具有优化的分子内电子转移速率，适合于氧到水的催化还原，这是生物系统中的重要反应，并且对燃料电池和空气电池能量转换具有重要意义。 此外，尽管寡聚体蛋白在许多细胞过程中发挥重要作用，但对多聚体蛋白获得其高阶结构的详细机制知之甚少。 PHS可以作为研究蛋白质结构、功能和寡聚体组装的模型系统。对SmbP的结构研究应该提供重要的见解，金属离子在蛋白质稳定性的作用，并推进蛋白质折叠和金属蛋白质设计领域的更广泛的影响，这项研究提供了一个很好的机会，培养研究生和高级本科生在多学科和多元文化的研究环境。 PI是一个代表性不足的群体的成员，积极参与指导本科和研究生阶段的少数民族学生。 将鼓励本科生参与这一项目，并将在亚利桑那州立大学少数民族服务方案的帮助下，重点招聘代表性不足的少数民族学生。

The goal of this project is to determine the crystal structure of two multicopper proteins by X-ray diffraction techniques. The first protein, the multicopper oxidase phenoxazinone synthase (PHS) from Streptomyces antibioticus, catalyzes the penultimate step in the biosynthesis of actinomycin D. The second protein, a small metal binding protein (SmbP) from the ammonia oxidizing bacterium Nitrosomonas europaea, is capable of binding up to six Cu(II) ions and displays unusual thermal stability in the presence of this metal. The three dimensional structures of PHS and SmbP are not known and their structures will be determined to provide structural support for biochemical studies being conducted on these proteins. The long-term goal of this research is to understand the relationship between protein structure, function, stability and oligomeric assembly in metalloproteins. Multicopper oxidases have optimized intramolecular electron transfer rates suitable for the catalytic reduction of oxygen to water, an important reaction in biological systems and with significant implications for fuel cells and air batteries energy conversion. In addition, relatively little is known about the detailed mechanisms whereby multimeric proteins acquire their higher order structure, even though oligomeric proteins play important roles in a number of cellular processes. PHS could serve as a model system for the study of the role of protein structure, function and oligomer assembly. Structural studies on SmbP should provide important insights into the role of metal ions in protein stability and advance the field of protein folding and metalloprotein design.In terms of broader impacts, this research provides an excellent opportunity to train graduate and advanced undergraduate students in a multidisciplinary and multicultural research environment. The PI, a member of an underrepresented group, is actively involved in mentoring minority students at the undergraduate and graduate levels. The participation of undergraduate students in this project will be encouraged and emphasis will be placed on the recruitment of underrepresented minority students with the help of minority serving programs at Arizona State University.