REDUCTION OF OXYGEN BY SULFATE REDUCING BACTERIA

描述：除了他们在生产中的良好作用， 大量有毒的硫化氢硫酸盐还原菌 已经证明是有用的，因为它们含有结构类似于 在哺乳动物中发现的更复杂的酶的结构域， 负责重要的生物功能。 近日 探索的系统，使氧气还原为水， 这些所谓的“严格厌氧菌”的发现， 含有铁-尿卟啉I作为辅基的蛋白质。 这 化合物，它积累在大量的一些遗传连锁 卟啉，迄今为止被认为是一种非代谢物。 这一发现，在 除了提供一种新的将氧气还原为水的生理方式外， 并首次显示了红氧还蛋白（Rd）在厌氧菌中的作用， 提出了尿卟啉I可能在 其他有机体。 拟议研究的具体目标是：1） 确定酶的三个关键组分中的两个的结构 一种以NADH为电子将氧还原为水的复合物 供体（第三个的三维结构，即Rd，已经 已知的分辨率低于1 A）; 2）详细检查电子 转移NAD-Rd-氧化还原酶（NRO）的性质; 3）描绘 Rd和NRO之间的相互作用域; 4）研究Rd和NRO之间的相互作用 Rd-氧-氧化还原酶（ROO）的三种氧化还原组分; 5）至 确定ROO的血红素C结合组分的化学结构。

DESCRIPTION: Beside their well established role in the production of massive concentrations of toxic hydrogen sulfides, sulfate-reducing bacteria have proven useful since they contain proteins whose structure is similar to domains of more complex enzymes which are found in mammals and where they are responsible for important biological functions. Recently, the exploration of the system that allows the reduction of oxygen to water in these so-called "strict anaerobes" has culminated with the discovery of a protein that contains Fe-Uroporphyrin I as a prosthetic group. This compound, which accumulates in large amounts in some genetically-linked porphyrias, was so far considered as a non-metabolite. This discovery, in addition to providing a new physiological way of reducing oxygen to water and of showing for the first time a role for rubredoxin (Rd) in an anaerobe, has raised the possibility that Uroporphyrin I may play important roles in other organisms. The specific aims of the proposed research are: 1) to determine the structure of two of the three key components of the enzymatic complex that allows the reduction of oxygen to water with NADH as electron donor (the three-dimensional structure of the third, namely Rd, is already known to a resolution below 1 A); 2) to examine in detail the electron transferring properties of the NAD-Rd-oxidoreductase (NRO); 3) to delineate the interacting domain between Rd and NRO; 4) to study the interplay between the three redox components of the Rd-Oxygen-oxidoreductase (ROO); 5) to determine the chemical structure of the heme c-binding component of ROO.