The H2 sensor of Ralstonia eutropha is a member of the subclass of regulatory [NiFe] hydrogenases
The H2 sensor of Ralstonia eutropha is a member of the subclass of regulatory [NiFe] hydrogenases
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DOI：
10.1128/jb.182.10.2716-2724.2000
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发表时间：
2000-05-01
影响因子：
3.2
通讯作者：
Friedrich, B
中科院分区：
文献类型：
--
作者：
Kleihues, L;Lenz, O;Friedrich, B
两种产生能量的氢化酶使好氧氢细菌Ralstonia eutropha（以前的Alcaligenes eutrophus）能够使用分子氢作为唯一的能量来源。含镍-铁的酶的复杂合成必须响应于H-2而被有效地调节，H-2在有氧环境中以低量可用。R.通过氢化酶样蛋白质实现真养型，该蛋白质与双组分调节系统一起控制氢化酶基因表达。在这项研究中，我们表明，H-2传感器的R。真养体是一种细胞质蛋白。虽然能够与氧化还原染料作为电子受体的H-2氧化，蛋白质不支持在没有产生能量的氢化酶的情况下的石自养生长。一个专门设计的R. eutropha提供了鉴定H-2传感器为含镍调节蛋白的基础。数据支持先前的结果，该结果表明传感器具有与原型[NiFe]氢化酶类似的活性位点（A. J. Pierik，M.施梅尔茨岛四旬斋，B。Friedrich和S. P. J. Albracht，FEES Lett. 438：231-235，1998）。它表明，除了酶活性的R，传感器的调节功能是镍依赖性的。结果表明，H-2传感需要一个积极的：[NiFe]氢化酶，留下的问题是开放的，是否只有H-2结合或随后的H-2氧化和电子转移过程是必要的信号。研究了R.在其它氢氧化细菌中也进行了研究的真养菌与一组典型的结构特征密切相关。因此，H-2传感器家族代表了一种新的[NiFe]氢化酶亚类，称为“调节性氢化酶”。"
Two energy-generating hydrogenases enable the aerobic hydrogen bacterium Ralstonia eutropha (formerly Alcaligenes eutrophus) to use molecular hydrogen as the sole energy source. The complex synthesis of the nickel-iron-containing enzymes has to be efficiently regulated in response to H-2, which is available in low amounts in aerobic environments. H-2 sensing in R. eutropha is achieved by a hydrogenase-like protein which controls the hydrogenase gene expression in concert with a two-component regulatory system. In this study we show that the H-2 sensor of R. eutropha is a cytoplasmic protein. Although capable of H-2 oxidation with redox dyes as electron accepters, the protein did not support lithoautotrophic growth in the absence of the energy-generating hydrogenases. A specifically designed overexpression system for R. eutropha provided the basis for identifying the H-2 sensor as a nickel-containing regulatory protein. The data support previous results which showed that the sensor has an active site similar to that of prototypic [NiFe] hydrogenases (A. J. Pierik, M. Schmelz, O. Lent, B. Friedrich, and S. P. J. Albracht, FEES Lett. 438:231-235, 1998). It is demonstrated that in addition to the enzymatic activity the regulatory function of the R, sensor is nickel dependent. The results suggest that H-2 sensing requires an active:[NiFe] hydrogenase, leaving the question open whether only H-2 binding or subsequent H-2 oxidation and electron transfer processes are necessary for signaling. The regulatory role of the H-2-sensing hydrogenase of R. eutropha, which has also been investigated in other hydrogen-oxidizing bacteria, is intimately correlated with a set of typical structural features. Thus, the family of H-2 sensors represents a novel subclass of [NiFe] hydrogenases denoted as the "regulatory hydrogenases."