CAREER: CAS: Spectroscopic Investigations of Biological Tellurium and Selenium Detoxification

碲（Te）是一种有毒的化学元素，由于其在电子、采矿、电池和光学中的使用增加，其作为环境污染物造成了潜在的问题。一组相关的碲离子抗性（TeR）蛋白已被发现在细菌中，能够生存暴露于碲离子。有了这个奖项，化学部的生命过程化学项目正在资助凯利N。来自里德学院的Chacón使用尖端的基于光的测量来表征这些细菌TeR蛋白的结构和生化特性。了解这些蛋白质有助于解释碲的相对未知的生物反应，同时探索潜在的生物修复方法，以开采碲作为一种宝贵的资源，并从污染的土壤中解毒碲。有了这个奖项，Chacón博士使用一种自信的，多方面的方法来提高科学，技术，工程和数学（STEM）学科中代表性不足的少数群体的学生的保留率。 她的计划通过强调基于能力，能力和兴趣原则的实践来增加STEM课程的包容性。她每年举办一次为期两天的会议和研讨会，将研究生的颜色和“其他”（包括不同的性别，低社会经济地位和第一代群体）从全国各地到里德学院提供科学和科学家的更广泛的观点，以学生在这个小的文科学院。抗碲（TeR）细菌的发现导致了质粒编码的抗碲操纵子的鉴定。我们对TeR基因表达的蛋白质的结构和功能的了解还有很大的差距。此外，缺乏信息存在的生化作用的碲，尽管它的相似性，其他基本的硫族元素（氧，硫，硒）。可溶性阴离子亚碲酸盐（TeO 3 [2-]）和碲酸盐（TeO 4 [2-]）是异生化合物。 关于其毒性和外排的生物化学知之甚少。细菌必须与暴露于非必需的有毒金属作斗争，并将能量消耗在快速解毒上，许多细菌已经对碲产生了抗性。凯利·N博士Chacón将应用基础生物化学，硒/碲/砷k边扩展X射线吸收精细结构（EXAFS），冷冻电子显微镜（Cryo EM）和晶体学的组合来表征基本的TeR蛋白质组分，并开始填补基础Te生物化学的空白。除了对硫族元素生物无机化学有新的认识外，对TeR蛋白质的了解还可能为开采这种宝贵的资源和对污染土壤进行解毒提供一种有趣的Te生物修复方法。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

Tellurium (Te) is a toxic chemical element that poses a potential problem as an environmental contaminant as a result of its increased use in electronics, mining, batteries, and optics. A set of related tellurium ion resistence (TeR) proteins have been discovered in bacteria that are able to survive exposure to tellurium ions. With this award, the Chemistry of Life Processes Program in the Chemistry Division is funding Dr. Kelly N. Chacón from Reed College to use cutting edge light-based measurements to characterize the structural and biochemical properties of these bacterial TeR proteins. Understanding these proteins helps explain the relatively unknown biological reactions of tellurium, while exploring potential bioremediation methods for mining Te as a precious resource and detoxifying Te from contaminated soil. With this award, Dr. Chacón uses an assertive, multifaceted approach to increase the retention of students from underrepresented minority groups in the science, technology, engineering, and mathematical (STEM) disciplines. Her program increases inclusiveness in the STEM curriculum by emphasizing practices based on the principles of belongingness, capacity, and interest. She is hosting a yearly two-day conference and workshop that will bring graduate students of color and “other” (including diverse gender, low-social economic status and first generation groups) from across the country to Reed College to provide a broader view of science and scientists to students at this small liberal arts college. The discovery of tellurium-resistant (TeR) bacteria has led to the identification of a plasmid-encoded tellurium-resistance operon. There is a large gap in our knowledge of structure and function of the proteins expressed from the TeR genes. Furthermore, a paucity of information exists on the biochemical role of Te, despite its similarity to the other essential chalcogens (oxygen, sulfur, and selenium). The soluble anions tellurite (TeO3[2-]) and tellurate (TeO4[2-]) are xenobiotic compounds. Little is understood about the biochemistry of their toxicity and efflux. Bacteria must contend with exposure to non-essential toxic metals and expend energy toward rapid detoxification, and many have developed resistance to Te. Dr. Kelly N. Chacón will apply a combination of fundamental biochemistry, Selenium/Tellurium/Arsenic k-edge Extended X-ray Absorption Fine Structure (EXAFS), Cryo-electron microscopy (Cryo EM), and crystallography to characterize the essential TeR protein components and begin to fill in the blanks of fundamental Te biochemistry. In addition to giving new insight into chalcogen bioinorganic chemistry, understanding of the TeR proteins could potentially provide an intriguing Te bioremediation method for mining this precious resource and for detoxifying contaminated soil.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.