Role of APS reductase in biogeochemical sulfur isotope fractionation
Role of APS reductase in biogeochemical sulfur isotope fractionation
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DOI：
10.1038/s41467-018-07878-4
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发表时间：
2019-01
影响因子：
16.6
通讯作者：
M. Sim;H. Ogata;W. Lubitz;J. Adkins;A. Sessions;V. Orphan;S. McGlynn
中科院分区：
文献类型：
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作者：
M. Sim;H. Ogata;W. Lubitz;J. Adkins;A. Sessions;V. Orphan;S. McGlynn
微生物硫酸盐还原（MSR）产生的硫同位素分馏提供了一些最早的生命证据，分馏值的长期变化反映了地球化学循环的变化。在这里，我们确定的硫同位素效应的酶腺苷磷酸硫酸还原酶（四月），这是目前在所有已知的生物进行MSR和催化的第一个还原步骤的途径和重新解释沉积硫同位素记录在地质时间。小的分级可能归因于低硫酸盐浓度和/或高呼吸速率，而大于Apr的分级则需要该代谢步骤的低化学势。由于太古代沉积物缺乏分馏超过20‰的Apr值，它们表明硫酸盐还原剂有足够的电子供体来驱动它们的代谢。大分馏后太古代沉积物是一致的下降有利的电子供体有氧和其他高潜力的代谢竞争对手的演变。
Sulfur isotope fractionation resulting from microbial sulfate reduction (MSR) provides some of the earliest evidence of life, and secular variations in fractionation values reflect changes in biogeochemical cycles. Here we determine the sulfur isotope effect of the enzyme adenosine phosphosulfate reductase (Apr), which is present in all known organisms conducting MSR and catalyzes the first reductive step in the pathway and reinterpret the sedimentary sulfur isotope record over geological time. Small fractionations may be attributed to low sulfate concentrations and/or high respiration rates, whereas fractionations greater than that of Apr require a low chemical potential at that metabolic step. Since Archean sediments lack fractionation exceeding the Apr value of 20‰, they are indicative of sulfate reducers having had access to ample electron donors to drive their metabolisms. Large fractionations in post-Archean sediments are congruent with a decline of favorable electron donors as aerobic and other high potential metabolic competitors evolved.