ELECTRON TRANSFER PATHWAYS/BLUE COPPER PROTEINS

反硝化细菌是管理废物的重要因素，以及 是大气中一氧化氮的来源。其中一个电子 硝酸盐最终通过NO2转化为氮气的转移途径 而不是，用于特别有效的反硝化细菌 粪产碱菌，菌株S-6，含铜亚硝酸盐还原酶， 以及一种蓝色蛋白质，它在正常情况下充当 将电子转移到亚硝酸还原酶，也可以起到 在氧气存在下的缓蚀剂。生物体“Achromobacter clecclastes” 在其反硝化途径中也含有一对类似的分子。 我们已经测定了其化学序列和蛋白质折叠。 粪链霉菌中的蓝色蛋白(铜氧还蛋白)，并计划继续 在高分辨率下阐明差异的结构细节 在分子的两个氧化态之间。结构就是这样的 一种可信的假说来解释两者之间的特殊性 蓝色蛋白及其亚硝酸盐还原酶位于该蛋白的C-末端螺旋 蓝色蛋白质，看起来也可以很容易地去除 蛋白水解性。这一假设将通过执行 切割和测试残留的相互作用的特异性。 这些蓝铜蛋白是专门设计用来结合 McMillin和Engeseth通过加热证明了铜的存在 相关蓝铜蛋白天青素的容量测量 除铜外的其他金属，不含任何金属。我们计划检查 用X射线衍射法测定了不含铜的天青的结构。 为了深入了解金属在蛋白质中的作用 正直。 最后，为了提供有关铜还蛋白1的合作伙伴的信息，我们 含铜亚硝酸还原酶的结构测定方案 出自“Achromobacter clecclastes”。这将揭示一个新的 一种铜蛋白质，以及允许我们检查的细节 它与其铜还蛋白(粪链霉菌的同源物)的相互作用， 在特定的电子转移链中的两个伙伴。

Denitrifying bacteria are important agents in managing waste, as well as being a source of nitric oxide in the atmosphere. One of the electron transfer pathways in which nitrates are converted eventually to N2 via NO2 and NO, utilizes, for the particularly potent denitrifying bacteria Alcaligenes faecalis, Strain S-6, a copper containing nitrite reductase, and a blue protein which which while normally acting as the agent which transfers an electron to the nitrite reductase, can also act as an inhibitor in the presence of O2. The organism "Achromobacter cycloclastes" also contains a similar pair of molecules in its denitrification pathway. We have determined the chemical sequence and the protein folding of the blue protein (cupredoxin) from A. faecalis, and plan to continue to elucidate the structural details at high resolution of the differences between the two oxidation states of the molecule. The structure is such that a plausible hypothesis for the origin of the specificity between the blue protein and its nitrite reductase resides in a C-terminal helix of the blue protein, which also looks as if could be easily removed proteolytically. This hypothesis will be tested by carrying out the cleavage and testing for remaining specificity of interaction. That these blue copper protein are specifically designed for binding just copper has been demonstrated by McMillin and Engeseth, by doing heat capacity measurements on the related blue copper protein, azurin, with metals other than copper bound, and without any metal. We plan to examine the structure of azurin without a copper, by X-ray diffraction methods, in order to gain insight into the role the metal plays in the protein integrity. Finally, in order to provide information on the partner of cupredoxin 1, we plan to determine the structure of the copper containing nitrite reductase from "Achromobacter cycloclastes". This will reveal the structure of a new kind of copper protein as well as allow us to examine the details of the interaction of it and its cupredoxin (a homolog of the A. faecalis one), two partners in a specific electron transfer chain.