Xia Qiangwei, Wang Tiansong, Hendrickson Erik L, Lie Thomas J, Hackett Murray, Leigh John A
Department of Chemical Engineering, Box 355014, University of Washington, Seattle, WA 98195, USA.
BMC Microbiol. 2009 Jul 23;9:149. doi: 10.1186/1471-2180-9-149.
Methanogenic Archaea play key metabolic roles in anaerobic ecosystems, where they use H2 and other substrates to produce methane. Methanococcus maripaludis is a model for studies of the global response to nutrient limitations.
We used high-coverage quantitative proteomics to determine the response of M. maripaludis to growth-limiting levels of H2, nitrogen, and phosphate. Six to ten percent of the proteome changed significantly with each nutrient limitation. H2 limitation increased the abundance of a wide variety of proteins involved in methanogenesis. However, one protein involved in methanogenesis decreased: a low-affinity [Fe] hydrogenase, which may dominate over a higher-affinity mechanism when H2 is abundant. Nitrogen limitation increased known nitrogen assimilation proteins. In addition, the increased abundance of molybdate transport proteins suggested they function for nitrogen fixation. An apparent regulon governed by the euryarchaeal nitrogen regulator NrpR is discussed. Phosphate limitation increased the abundance of three different sets of proteins, suggesting that all three function in phosphate transport.
The global proteomic response of M. maripaludis to each nutrient limitation suggests a wider response than previously appreciated. The results give new insight into the function of several proteins, as well as providing information that should contribute to the formulation of a regulatory network model.
产甲烷古菌在厌氧生态系统中发挥着关键的代谢作用，它们利用氢气和其他底物来产生甲烷。马氏甲烷球菌是研究对营养限制的全球响应的一个模型。
我们使用高覆盖度定量蛋白质组学来确定马氏甲烷球菌对氢气、氮和磷的生长限制水平的响应。每种营养限制下，蛋白质组中有6%至10%发生了显著变化。氢气限制增加了参与甲烷生成的多种蛋白质的丰度。然而，有一种参与甲烷生成的蛋白质减少了：一种低亲和力的[铁]氢化酶，当氢气充足时，它可能比高亲和力机制占主导地位。氮限制增加了已知的氮同化蛋白质。此外，钼酸盐转运蛋白丰度的增加表明它们在固氮中起作用。讨论了一个由广古菌氮调节因子NrpR调控的明显操纵子。磷限制增加了三组不同蛋白质的丰度，表明这三组蛋白质都在磷转运中起作用。
马氏甲烷球菌对每种营养限制的整体蛋白质组响应表明其响应比以前认识到的更广泛。这些结果为几种蛋白质的功能提供了新的见解，同时也提供了有助于构建调控网络模型的信息。
