Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA.
Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA.
Commun Biol. 2024 Oct 16;7(1):1337. doi: 10.1038/s42003-024-07049-w.
Molybdoenzymes are essential in global nitrogen, carbon, and sulfur cycling. To date, the only known bioavailable source of molybdenum (Mo) is molybdate. However, in the sulfidic and anoxic (euxinic) habitats that predominate in modern subsurface environments and that were pervasive prior to Earth's widespread oxygenation, Mo occurs as soluble tetrathiomolybdate ion and molybdenite mineral that is not known to be bioavailable. This presents a paradox for how organisms obtain Mo to support molybdoenzymes in these environments. Here, we show that tetrathiomolybdate and molybdenite sustain the high Mo demand of a model anaerobic methanogen, Methanococcus maripaludis, grown via Mo-dependent formate dehydrogenase, formylmethanofuran dehydrogenase, and nitrogenase. Cells grown with tetrathiomolybdate and molybdenite have similar growth kinetics, Mo content, and transcript levels of proteins involved in Mo transport and cofactor biosynthesis when compared to those grown with molybdate, implying similar mechanisms of transport and cofactor biosynthesis. These results help to reconcile the paradox of how Mo is acquired in modern and ancient anaerobes and provide new insight into how molybdoenzymes could have evolved prior to Earth's oxygenation.
钼酶在全球氮、碳和硫循环中是必不可少的。迄今为止，已知的唯一生物可利用钼（Mo）来源是钼酸盐。然而，在现代地下环境中占主导地位的硫化物和缺氧（缺氧）栖息地，以及在地球广泛氧化之前普遍存在的缺氧环境中，Mo 以可溶性四硫代钼酸盐离子和辉钼矿矿物的形式存在，而这些形式的 Mo 并不被认为是生物可利用的。这给生物体如何在这些环境中获得钼以支持钼酶提出了一个悖论。在这里，我们表明，四硫代钼酸盐和辉钼矿维持了模式厌氧甲烷菌 Methanococcus maripaludis 的高 Mo 需求，该菌通过 Mo 依赖性甲酸脱氢酶、甲酰甲硫氨酸脱氢酶和固氮酶生长。与用钼酸盐生长的细胞相比，用四硫代钼酸盐和辉钼矿生长的细胞具有相似的生长动力学、Mo 含量以及参与 Mo 转运和辅助因子生物合成的蛋白质的转录水平，这意味着转运和辅助因子生物合成的机制相似。这些结果有助于调和现代和古代厌氧菌中 Mo 是如何获得的悖论，并为地球氧化之前钼酶是如何进化的提供了新的见解。
