Institut für Biologie, Mikrobiologie, Humboldt-Universität zu Berlin, Chausseestrasse 117, Berlin, Germany.
Proteomics. 2009 Nov;9(22):5132-42. doi: 10.1002/pmic.200900333.
Ralstonia eutropha H16 is an H(2)-oxidizing, facultative chemolithoautotroph. Using 2-DE in conjunction with peptide mass spectrometry we have cataloged the soluble proteins of this bacterium during growth on different substrates: (i) H(2) and CO(2), (ii) succinate and (iii) glycerol. The first and second conditions represent purely lithoautotrophic and purely organoheterotrophic nutrition, respectively. The third growth regime permits formation of the H(2)-oxidizing and CO(2)-fixing systems concomitant to utilization of an organic substrate, thus enabling mixotrophic growth. The latter type of nutrition is probably the relevant one with respect to the situation faced by the organism in its natural habitats, i.e. soil and mud. Aside from the hydrogenase and Calvin-cycle enzymes, the protein inventories of the H(2)-CO(2)- and succinate-grown cells did not reveal major qualitative differences. The protein complement of the glycerol-grown cells resembled that of the lithoautotrophic cells. Phosphoenolpyruvate (PEP) carboxykinase was present under all three growth conditions, whereas PEP carboxylase was not detectable, supporting earlier findings that PEP carboxykinase is alone responsible for the anaplerotic production of oxaloacetate from PEP. The elevated levels of oxidative stress proteins in the glycerol-grown cells point to a significant challenge by ROS under these conditions. The results reported here are in agreement with earlier physiological and enzymological studies indicating that R. eutropha H16 has a heterotrophic core metabolism onto which the functions of lithoautotrophy have been grafted.
氢营养型罗尔斯通氏菌 H16 是一种 H(2)氧化、兼性化能自养细菌。我们使用 2-DE 结合肽质量指纹图谱技术，对该菌在不同底物上生长时的可溶性蛋白进行了编目：（i）H(2)和 CO(2)，（ii）琥珀酸盐和（iii）甘油。第一和第二条件分别代表纯化能自养和纯有机异养营养。第三种生长方式允许在利用有机底物的同时形成 H(2)氧化和 CO(2)固定系统，从而实现混合营养生长。后一种营养类型可能与该生物体在其自然栖息地（即土壤和泥浆）中所面临的情况有关。除了氢化酶和卡尔文循环酶外，H(2)-CO(2)和琥珀酸盐生长细胞的蛋白质库没有显示出主要的定性差异。甘油生长细胞的蛋白质成分与化能自养细胞相似。磷酸烯醇丙酮酸（PEP）羧激酶存在于所有三种生长条件下，而 PEP 羧化酶则无法检测到，这支持了早先的发现，即 PEP 羧激酶是唯一负责从 PEP 产生草酰乙酸的氨同化作用的酶。甘油生长细胞中氧化应激蛋白水平升高表明在这些条件下 ROS 会产生显著的挑战。这里报告的结果与早期的生理和酶学研究一致，表明罗尔斯通氏菌 H16 具有异养核心代谢途径，化能自养功能已被嫁接到该途径上。
