Regulation of biological nitrogen fixation
Regulation of biological nitrogen fixation
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DOI：
10.1093/jn/130.5.1081
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发表时间：
2000-05-01
影响因子：
4.2
通讯作者：
Ludden, PW
中科院分区：
文献类型：
--
作者：
Halbleib, CM;Ludden, PW
生物固氮是仅在某些原核生物中发现的过程，由固氮酶复合物催化。含有固氮酶的细菌占据着不可或缺的生态位，为全球氮循环提供固定氮。由于在氮循环中的这种起始作用，固氮生物几乎存在于所有生态系统中，其代表环境多种多样，如需氧土壤（例如固氮菌属）、海洋表层（毛藻）和豆科植物根部的特殊根瘤（根瘤菌）。在任何生态系统中，固氮生物必须对不同的环境条件做出反应以调节 固氮过程极其繁重。所有表征的固氮生物都在转录水平上调节固氮酶。较小的一组还拥有快速作用的翻译后调节系统。尽管固氮酶的序列和结构几乎没有明显的变化，但固氮酶的调节方案似乎几乎与固氮物种一样多。本文描述了各种固氮细菌中描述的固氮酶功能、转录控制和翻译后调节的范例，以及这些方案的变化。调节是在分子基础上描述的，重点是负责控制固氮的蛋白质的功能和结构特征。
Biological nitrogen fixation, a process found only in some prokaryotes, is catalyzed by the nitrogenase enzyme complex. Bacteria containing nitrogenase occupy an indispensable ecological niche, supplying fixed nitrogen to the global nitrogen cycle. Due to this inceptive role in the nitrogen cycle, diazotrophs are present in virtually all ecosystems, with representatives in environments as varied as aerobic soils (e.g., Azotobacter species), the ocean surface layer (Trichodesmium) and specialized nodules in legume roots (Rhizobium), In any ecosystem, diazotrophs must respond to varied environmental conditions to regulate the tremendously taxing nitrogen fixation process. All characterized diazotrophs regulate nitrogenase at the transcriptional level. A smaller set also possesses a fast-acting post-translational regulation system. Although there is little apparent variation in the sequences and structures of nitrogenases, there appear to be almost as many nitrogenase-regulating schemes as there are nitrogen-fixing species. Herein are described the paradigms of nitrogenase function, transcriptional control and post-translational regulation, as well as the variations on these schemes, described in various nitrogen-fixing bacteria. Regulation is described on a molecular basis, focusing on the functional and structural characteristics of the proteins responsible for control of nitrogen fixation.