Institute for Genomic Biology, University of Illinois, Urbana, IL 61801, USA.
Science. 2012 Aug 31;337(6098):1104-7. doi: 10.1126/science.1219875.
Relative to the atmosphere, much of the aerobic ocean is supersaturated with methane; however, the source of this important greenhouse gas remains enigmatic. Catabolism of methylphosphonic acid by phosphorus-starved marine microbes, with concomitant release of methane, has been suggested to explain this phenomenon, yet methylphosphonate is not a known natural product, nor has it been detected in natural systems. Further, its synthesis from known natural products would require unknown biochemistry. Here we show that the marine archaeon Nitrosopumilus maritimus encodes a pathway for methylphosphonate biosynthesis and that it produces cell-associated methylphosphonate esters. The abundance of a key gene in this pathway in metagenomic data sets suggests that methylphosphonate biosynthesis is relatively common in marine microbes, providing a plausible explanation for the methane paradox.
相对于大气而言，海洋中有很大一部分区域的甲烷处于过饱和状态；然而，这种重要的温室气体的来源仍然是个谜。有人提出，磷饥饿的海洋微生物对甲基膦酸的分解代谢会伴随着甲烷的释放，可以用来解释这一现象，但甲基膦酸并不是一种已知的天然产物，也没有在自然系统中检测到。此外，从已知的天然产物中合成它需要未知的生物化学知识。在这里，我们证明海洋古菌 Nitrosopumilus maritimus 编码了一种甲基膦酸生物合成途径，并产生细胞相关的甲基膦酸酯。该途径中的一个关键基因在宏基因组数据集的丰度表明，甲基膦酸的生物合成在海洋微生物中相对普遍，为甲烷悖论提供了一个合理的解释。
