Ulrich Emily C, Kamat Siddhesh S, Hove-Jensen Bjarne, Zechel David L
Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, United States.
Indian Institute of Science Education and Research (IISER), Pune, Maharashtra, India.
Methods Enzymol. 2018;605:351-426. doi: 10.1016/bs.mie.2018.01.039. Epub 2018 May 3.
Inorganic phosphate is essential for all life forms, yet microbes in marine environments are in near constant deprivation of this important nutrient. Organophosphonic acids can serve as an alternative source of inorganic phosphate if microbes possess the appropriate biochemical pathways that allow cleavage of the stable carbon-phosphorus bond that defines this class of molecule. One prominent source of inorganic phosphate is methylphosphonic acid, which is found as a constituent of marine-dissolved organic matter. The cycle of biosynthesis and catabolism of methylphosphonic acid by marine microbes is the likely source of supersaturating levels of methane in shallow ocean waters. This review provides an overview of the rich biochemistry that has evolved to synthesize methylphosphonic acid and catabolize this molecule into Pi and methane, with an emphasis on the reactions catalyzed by methylphosphonic acid synthase MpnS and the carbon-phosphorus lyase system. The protocols and experiments that are described for MpnS and carbon-phosphorus lyase provide a foundation for studying the structures and mechanisms of these and related enzymes.
无机磷酸盐对所有生命形式都至关重要，但海洋环境中的微生物几乎一直处于这种重要营养素匮乏的状态。如果微生物拥有适当的生化途径，能够裂解定义这类分子的稳定碳 - 磷键，有机膦酸就可以作为无机磷酸盐的替代来源。无机磷酸盐的一个重要来源是甲基膦酸，它是海洋溶解有机物的组成成分之一。海洋微生物对甲基膦酸的生物合成和分解代谢循环很可能是浅海海水中甲烷过饱和水平的来源。本综述概述了为合成甲基膦酸并将该分子分解为无机磷酸盐和甲烷而进化出的丰富生物化学过程，重点介绍了由甲基膦酸合酶MpnS和碳 - 磷裂解酶系统催化的反应。针对MpnS和碳 - 磷裂解酶所描述的实验方案为研究这些及相关酶的结构和机制奠定了基础。
