Intermediates in the transformation of phosphonates to phosphate by bacteria.
Intermediates in the transformation of phosphonates to phosphate by bacteria.
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DOI：
10.1038/nature10622
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发表时间：
2011-11-16
期刊：
影响因子：
64.8
通讯作者：
Raushel, Frank M.
中科院分区：
文献类型：
--
作者：
Kamat, Siddhesh S.;Williams, Howard J.;Raushel, Frank M.
磷是所有已知生命形式的基本元素。在生命系统中，磷是核酸、碳水化合物和磷脂的组成部分，它作为磷酸盐的衍生物被结合在一起。然而，大多数革兰氏阴性菌在磷酸盐饥饿的条件下都有能力利用磷酸盐作为磷的营养来源。在这些生物体中，甲基磷酸盐被转化为磷酸盐和甲烷。从形式上讲，这种转化是碳-磷(C-P)键的水解性断裂，但经过二十多年的努力，烷基膦酸酯活化和转化为磷酸盐和烷烃的一般酶机理尚未阐明。C-P键断裂的实际机制可能是基于自由基的转变。在大肠杆菌中，C-P裂解酶反应的催化机制已定位于phn基因簇。该操纵子由14个基因phnC、phnD、…组成、phnP.遗传和生化实验证明，基因phnG、phnH、…，phnMen编码对磷酸盐转化为磷酸盐至关重要的蛋白质，操纵子中其他基因编码的蛋白质具有辅助功能，，，。对于被认为对C-P键断裂至关重要的七种蛋白质中的任何一种，都没有功能注释。在这里，我们展示了甲基膦与三磷酸镁反应生成α-d-核糖-1-甲基膦-5-三磷酸(RPnTP)和腺嘌呤。RPnTP的三磷酸部分被水解成焦磷酸和α-d-核糖-1-甲基膦-5-磷酸(PRPn)。在α-腺苷-L-蛋氨酸存在下，PRPn的C-P键随后在基于自由基的反应中裂解，生成PRPn-d-核糖-1，2-环磷酸-5-磷酸和甲烷。世界各地生产了大量的磷酸盐，用于工业加工、洗涤剂、除草剂和制药。我们阐明了烷基膦酸盐生物降解的化学步骤，展示了这些化合物如何被代谢和循环为磷酸盐。
Phosphorus is an essential element for all known forms of life. In living systems, phosphorus is an integral component of nucleic acids, carbohydrates and phospholipids, where it is incorporated as a derivative of phosphate. However, most Gram-negative bacteria have the capability to use phosphonates as a nutritional source of phosphorus under conditions of phosphate starvation. In these organisms, methylphosphonate is converted to phosphate and methane. In a formal sense, this transformation is a hydrolytic cleavage of a carbon–phosphorus (C–P) bond, but a general enzymatic mechanism for the activation and conversion of alkylphosphonates to phosphate and an alkane has not been elucidated despite much effort for more than two decades. The actual mechanism for C–P bond cleavage is likely to be a radical-based transformation. InEscherichia coli, the catalytic machinery for the C–P lyase reaction has been localized to thephngene cluster. This operon consists of the 14 genesphnC,phnD, …,phnP. Genetic and biochemical experiments have demonstrated that the genesphnG,phnH, …,phnMencode proteins that are essential for the conversion of phosphonates to phosphate and that the proteins encoded by the other genes in the operon have auxiliary functions,,,,. There are no functional annotations for any of the seven proteins considered essential for C–P bond cleavage. Here we show that methylphosphonate reacts with MgATP to form α-d-ribose-1-methylphosphonate-5-triphosphate (RPnTP) and adenine. The triphosphate moiety of RPnTP is hydrolysed to pyrophosphate and α-d-ribose-1-methylphosphonate-5-phosphate (PRPn). The C–P bond of PRPn is subsequently cleaved in a radical-based reaction producing α-d-ribose-1,2-cyclic-phosphate-5-phosphate and methane in the presence ofS-adenosyl-l-methionine. Substantial quantities of phosphonates are produced worldwide for industrial processes, detergents, herbicides and pharmaceuticals,,. Our elucidation of the chemical steps for the biodegradation of alkylphosphonates shows how these compounds can be metabolized and recycled to phosphate.
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影响因子：
14.8
作者：
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