COLLABORATIVE RESEARCH: Redox metallo-proteins and conformational gating in electron transfer to ferric minerals

合作研究：电子转移到铁矿物中的氧化还原金属蛋白和构象门控

• 批准号: 0434023
• 负责人: Timothy Magnuson
• 金额: $ 8.53万
• 依托单位: Idaho State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-10-01 至 2009-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0434023&HistoricalAwards=false
• 关键词: COLLABORATIVE; RESEARCH; Redox; metallo; proteins

This collaborative project between researchers at the University of Wyoming and Idaho State University will examine the transfer of electrons from mineral oxide surfaces to c-type cytochromes from the cell membranes of metal-reducing microbes. Oxide interactions with iron-sulfur proteins and other biomolecules will also be investigated. The main hypothesis under investigation is to see if oxide surfaces "trigger" conformation changes in proteins on mineral surfaces that can result in a shift in the redox potential of the protein that favors electron transfer. This study was motivated because metal reducing microorganisms and how they interact with their environment are of great interest not only because they are involved in the global redox cycling of iron and other metals, but also because they are able to chemically immobilize a variety of toxic metals in the environment, including radionuclides. Research will be carried out with commercially available proteins, as well as proteins purified from metal-reducing bacteria in the laboratory. Sorption studies to understand the aqueous conditions under which optimal protein-mineral interaction happen will be conducted. The research will examine outer membrane protein adsorption to hematite and goethite as a function of pH, ionic strength, time, temperature and phosphate composition. The redox state of proteins in the adsorbed state under different geochemical conditions will also be examined. Surface imaging techniques and characterizations such as atomic force and scanning tunneling electron microscopy will be carried out as will XANES, EXAFS, and UV-VIS spectroscopy. Second harmonic generation will be used to examine the orientation of selected molecules adsorbed to oxide surfaces. Changes in the redox properties of the proteins under investigation will be correlated with conformational changes, and the polarizability of the adsorbed molecules and dimensions of the molecules in the adsorbed state will be determined. Broader impacts of this study include the scientific basis for development of protein-functionalized electrodes that will allow us to utilize the specific function of proteins in sensor applications, bioremediation strategies for toxic metals, and improving our understanding of bioremediation of metals.

怀俄明州大学和爱达荷州州立大学的研究人员之间的这个合作项目将研究电子从矿物氧化物表面转移到金属还原微生物细胞膜的c型细胞色素。 氧化物与铁硫蛋白和其他生物分子的相互作用也将被研究。 正在研究的主要假设是，看看氧化物表面是否“触发”矿物表面上蛋白质的构象变化，这可能导致蛋白质的氧化还原电位发生变化，有利于电子转移。这项研究的动机是因为金属还原微生物以及它们如何与环境相互作用引起了极大的兴趣，不仅因为它们参与了铁和其他金属的全球氧化还原循环，而且还因为它们能够化学还原环境中的各种有毒金属，包括放射性核素。 研究将使用市售蛋白质以及从实验室金属还原细菌中纯化的蛋白质进行。将进行吸附研究，以了解最佳蛋白质-矿物质相互作用发生的水性条件。 该研究将研究外膜蛋白吸附到赤铁矿和针铁矿作为pH值，离子强度，时间，温度和磷酸盐组成的函数。还将研究在不同地球化学条件下吸附态蛋白质的氧化还原状态。 表面成像技术和表征，如原子力和扫描隧道电子显微镜将进行XANES，EXAFS和紫外可见光谱。二次谐波产生将被用来检查选定的分子吸附到氧化物表面的取向。 研究中的蛋白质的氧化还原性质的变化将与构象变化相关，并且将确定吸附分子的极化率和吸附状态下分子的尺寸。 这项研究的更广泛的影响包括开发蛋白质功能化电极的科学基础，这将使我们能够利用蛋白质在传感器应用中的特定功能，有毒金属的生物修复策略，以及提高我们对金属生物修复的理解。