Acquisition and Internalization of Copper by Methanotrophs

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。甲烷obactin （Mb）是一种从甲烷营养细菌中分离出来的铜螯合小分子，甲烷是一种利用甲烷作为唯一碳源的生物。甲烷obactin促进铜的吸收，也可能在调节甲烷单氧化酶（MMO）酶的表达、含铜微粒MMO （pMMO）的催化作用以及抵御铜毒性和由此产生的氧化应激中起作用。虽然在过去几年中对Cu-Mb的结构和功能有了一些了解，但主要问题仍未得到解答。首先，Cu-Mb仅从一种生物中被表征。目前尚不清楚不同物种的Mb分子是否具有相似的结构。从三种类型的甲烷氧化菌中分离Cu-Mb，并通过分析，光谱和结构方法进行表征。这些数据将有助于深入了解Mb的结构多样性及其在种间金属离子竞争中的作用。其次，很明显，当被剥夺铜时，甲烷氧化菌会分泌Mb到它们的生长培养基中，但不知道Cu-Mb是如何被带回细胞的。Cu-Mb的直接摄取将在实验中建立，各种生物物理、生化和遗传方法将用于鉴定参与Cu-Mb摄取的蛋白质。广泛的影响甲烷氧化菌的生长，Mb的分离和光谱表征已被证明是优秀的培训项目。几名本科生将从事从不同生物体中分离Mb的工作。除了让本科生接触到这个高度协作的跨学科研究项目外，少数族裔学生将有机会作为西北大学的研究生，并通过芝加哥州立大学-北方大学硕士到博士的桥梁项目。了解甲烷氧化菌如何获取甲烷氧化所需的铜离子将影响各种环境下的温室气体模型，特别是与从矿物来源获取铜有关的模型。此外，Mb在半导体工业中有潜在的应用价值，可以从废水中去除铜。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). Methanobactin (Mb) is a small copper-chelating molecule isolated from methanotrophic bacteria, organisms that utilize methane as their sole carbon source. Methanobactin facilitates copper uptake and may also function in regulation of methane monooxygenase (MMO) enzyme expression, catalysis by the copper-containing, particulate MMO (pMMO), and defense against copper toxicity and resultant oxidative stress. Although some insight into Cu-Mb structure and function has been gained in the past few years, major questions remain unanswered. First, Cu-Mb has only been characterized from one organism. It is not known whether Mb molecules from different species have similar structures. Cu-Mb from three types of methanotrophs will be isolated and characterized by analytical, spectroscopic, and structural methods. These data will provide insight into the structural diversity of Mb and into its role in interspecies competition for metal ions. Second, it is clear that methanotrophs secrete Mb into their growth medium when deprived of copper, but it is not known how Cu-Mb is taken back into the cell. Direct uptake of Cu-Mb will be established experimentally and a variety of biophysical, biochemical, and genetic approaches will be utilized to identify proteins involved in Cu-Mb uptake. Broader ImpactThe growth of methanotrophs, Mb isolation, and spectroscopic characterization have proven to be excellent training projects. Several undergraduate students will work on isolating Mb from different organisms. In addition to exposing undergraduates to this highly collaborative, interdisciplinary research project, underrepresented minority students will have the opportunity to participate as graduate students at Northwestern and through the Chicago State University-NU Masters to the PhD Bridge Program. An understanding of how methanotrophs acquire essential copper ions for methane oxidation will impact greenhouse gas models for various environments, particularly as pertains to acquisition of copper from mineral sources. In addition, Mb is potentially applicable in the semiconductor industry to remove copper from wastewater.