RIG: The Physiological Significance of Microbial Mn(II) Oxidation

锰（Mn）氧化微生物通过将可溶性Mn（II）氧化成不溶性Mn（III，IV）氧化物而在Mn的全球地球化学循环中发挥不可或缺的作用。除了锰，这些微生物影响其他金属，硫和碳的命运，因此可以用于生物修复。 这些微生物超出锰循环的影响是由Mn（II）的氧化形成的生物锰氧化物的非常反应性和吸附性的结果。 尽管Mn（II）氧化微生物对生物地球化学循环有重要影响，但我们对微生物如何以及为什么氧化Mn（II）的细胞和分子水平知之甚少。 最近确定了一种新的过氧化物酶氧化锰（II）在α变形菌。 这种新的Mn（II）氧化酶提出了关于该过程以及这种独特的酶如何发挥作用的问题。理解任何类型的Mn（II）氧化蛋白的机制已经被从天然来源获得纯化的Mn（II）氧化蛋白的极端困难所阻碍。 因此，本项目将在大肠杆菌中异源表达该蛋白，并表征这种新的Mn（II）氧化蛋白。 了解这种新的酶将提供所需的深入了解锰（II）氧化的机制，并将扩大我们的生物化学多样性和蛋白质功能的看法。 该项目还研究了细菌氧化Mn（II）的原因。 该研究将确定锰氧化物是否提供细胞保护并影响细胞内锰浓度。总之，这些研究将改变我们的观点，锰（II）氧化作为一个重要的生理和地球化学过程。更广泛的影响锰（II）氧化细菌产生的锰氧化物可以在金属和有机污染场地的生物修复中发挥重要作用。 了解细菌氧化Mn（II）的方式和原因有可能更好地控制这一过程，提高其适用性。 这项研究将主要由本科研究生进行。 学生们将合作，并将被鼓励发表和介绍他们的结果在地方和国家会议。 这些项目是学生在地质微生物学，生物化学和生物技术的极好的培训机会。 跨学科的培训将使学生准备在生物技术行业，研究生院或卫生专业学校取得成功。 加州州立大学是一所西班牙裔服务机构，对代表性不足的学生进行培训将是该项目的一个组成部分。

Manganese (Mn) oxidizing microbes play an integral role in the global biogeochemical cycling of Mn by oxidizing soluble Mn(II) to insoluble Mn(III,IV) oxides. Beyond Mn, these microbes affect the fate of other metals, sulfur, and carbon and therefore can be used in bioremediation. The influence of these microbes beyond the Mn cycle is a result of the very reactive and adsorptive properties of biogenic Mn oxides formed by oxidation of Mn(II). Despite the important influence Mn(II) oxidizing microbes can have on biogeochemical cycles, we know very little on the cellular and molecular level about how and why microbes oxidize Mn(II). A new peroxidase enzyme was recently determined to oxidize Mn(II) in alpha proteobacteria. This new Mn(II) oxidizing enzyme raises questions about the process as well as how this unique enzyme may function. Understanding the mechanism of any type of Mn(II) oxidizing protein has been hindered by the extreme difficulty in obtaining purified Mn(II) oxidizing proteins from native sources. Therefore, this project will heterologously express this protein in Escherichia coli and characterize this new Mn(II) oxidizing protein. An understanding of this new enzyme will provide needed insight into the mechanism of Mn(II) oxidation and will expand our view of biochemical diversity and protein function. This project also investigates why bacteria oxidize Mn(II). The research will determine if Mn oxides provide cellular protection and affect intracellular manganese concentrations. Together, these studies will transform our view of Mn(II) oxidation as an important physiological as well as biogeochemical process.Broader ImpactsThe Mn oxides produced by Mn(II) oxidizing bacteria can play an important role in bioremediation of metal and organic contaminated sites. Understanding how and why bacteria oxidize Mn(II) has the potential to better control this process, increasing its applicability. The research will be performed primarily by undergraduate research students. The students will work collaboratively and will be encouraged to publish and present their results at local and national meetings. These projects are excellent training opportunities for students in geomicrobiology, biochemistry, and biotechnology. The interdisciplinary training will yield students ready to succeed in the biotechnology industry, graduate school, or a health professional school. California State University is a Hispanic serving institution and training of underrepresented students will be an integral part of this project.