极端嗜酸热古菌Metallosphaera cuprina硫代谢途径中关键蛋白的功能研究

(限400字)：嗜酸热古菌在自然界硫、碳、氧及金属元素等的地球化学循环及生物冶金过程中起重要作用，它们通过复杂的硫代谢系统完成对不同价态硫的氧化，获取生长和代谢所需能量。这些菌中还有许多硫代谢相关蛋白的功能未知。Metallosphaera cuprina Ar-4是从热泉中分离获得的嗜酸热古菌，能够氧化单质硫，连四硫酸钾和低品位硫化矿, 具有在高温生物冶金工业中的应用潜力。前期研究构建了该菌的代谢网络，发现了可能参与硫代谢过程的关键基因和蛋白。本项目拟以M. cuprina为材料，结合酶活分析，产物测定及RT-PCR等方法，研究蛋白在硫代谢中的作用；利用基因敲除和互补、蛋白质与蛋白质、蛋白质和DNA相互作用等技术手段，解析蛋白的生理功能；阐述硫代谢关键蛋白与含硫底物、DNA分子及相关蛋白间的作用机制；揭示M. cuprina的硫代谢机制，为加速该菌在生物冶金过程中的应用提供理论依据。

Extremely thermoacidophilic Archaea from the family Sulfolobaceae, including genus Sulfolobus, Acidianus, and Metallosphaera, contribute greatly to sulfur, carbon, oxygen and metallic elements biogeochemical cycling, as well as in biohydrometallurgy and waste water treatment processes. They oxidize the sulfur with different valence and obtain the energy for growth and metabolism. Nevertheless, the functions of many proteins in the sulfur metabolism keep unknown. The thermoacidophilic archaeon Metallosphaera cuprina was isolated from a sulfuric hot spring which is able to oxidize elemental sulfur, tetrathionate, pyrite, and a range of low-grade ores, thus is attractive to biomining industry. Recently, we have explored the sulfur metabolism of M. cuprina with genomic, proteomic, and biochemical tools. A hypothetical model of sulfur metabolism in M. cuprina was proposed on proteomic and genomic data, and key proteins that involved in sulfur metabolism have been found. In this research, the functions of the proteins involved in sulfur metabolism will be identified via analysis of enzyme activities and gene knockout/complementation approach. Furthermore, the mechanism of sulfur metabolism will be analyzed. Our aim is to reveal the sulfur metabolism pathway and mechanism in M. cuprina. This research is helpful to understand the life styles of the archaea.