EAPSI:Investigating Roles of Putative Phosphonatases from the Extreme Bacterium Synechococcus

磷是地球上第十一种最丰富的元素，也是生命所必需的。磷酸酯是一种含有C-O-P键的化合物，构成了DNA和RNA的骨架，也是分子能量分子ATP的组成部分。因此，对磷酸酯的研究已经有几十年的历史了。研究较少的是有机磷酸盐，这是一种含有C-P键的化合物。有机磷酸盐被认为在原始地球上占主导地位，当时的氧气浓度可能比今天低。最近，人们注意到有机磷酸盐作为商业产品的重要性，从抗生素到杀菌剂，以及在为生活在极端环境中的有机体提供营养方面。此外，有机磷酸盐最近被认为是海洋磷循环的重要组成部分，占海洋溶解有机磷的25%。因此，了解有机磷的分解和利用对于理解环境中的磷循环是很重要的。将与北海道大学的Taichi Takasuka教授合作，制造并测试能够分解这些化合物的酶的功能。它们有可能有能力以一种以前从未报道过的方式分解有机磷酸盐。最广为人知的有机磷分解代谢的微生物途径是C-P裂解酶，这是一种多亚单位酶复合体，在所有研究的细菌中，它都受单一的磷酸激活启动子的控制。C-P裂解酶？S机制是新近提出的，同时也是有机磷分解代谢的替代机制。在这些可供选择的途径中，大多数至少已经部分确定了特征。然而，最近的三篇论文提供了在弯曲杆菌、螺旋杆菌和聚球藻中尚不清楚的磷酸盐降解分解代谢途径的证据。具体地说，在聚球藻属中。从黄石国家公园分离出来的基因产物与有机磷分解代谢有关，但既没有得到证实，也没有确定其特征。这些假定的磷酸酶将使用基于小麦胚芽的无细胞蛋白生产系统来表达，并使用定量质谱学(MS)进行生化表征。本研究推测的与磷酸分解代谢有关的磷酸酶(Phnase)及其代谢产物可能揭示了这一重要的含磷化合物分解的新机制。该NSF EAPSI奖是与日本科学促进会合作资助的。

Phosphorus is the eleventh most abundant element on the planet, and essential to life. Phosphate esters, compounds that contain a C-O-P bond, make up the backbones of DNA and RNA and are also a component of the molecular energy molecule ATP. Thus, phosphate esters have been well studied for many decades. Less thoroughly examined are organophosphanates, compounds which contain a C-P bond. Organophosphonates are thought to have predominated on primitive Earth, when oxygen concentration was likely lower than today. More recently, organophosphonates have been noted for their importance as commercial products, from antibiotics to fungicides, and in providing nutrients for organisms living in extreme environments. Additionally, organophosphonates have recently been recognized as an important component of the marine phosphorus cycle, accounting for up to 25% of oceanic dissolved organic phosphate. Understanding organophosphonate breakdown and utilization is thus important for understanding environmental phosphorus cycling. Work will be conducted with Professor Taichi Takasuka, at Hokkaido University, to make and test the function of enzymes proposed to be able to break down these compounds. It is possible that they have the ability to break down organophosphonates in a way that has never been reported before. The most well known microbial pathway for organophosphonate catabolism is that of C-P lyase, a multi-subunit enzyme complex that, in all bacteria studied, is under control of a single, phosphate-activated promoter. C-P lyase?s mechanism has recently been proposed, along with mechanisms for alternative organophosphonate catabolism. Of these alternative pathways, most have been at least partially characterized. However, three recent publications present evidence for as-yet-uncharacterized catabolic pathways of phosphonate degradation in Campylobacter spp., Heliobacter spp., and Synechococcus spp. Specifically, in Synechoccus spp. isolated from Yellowstone National Park, gene products have been implicated in organophosphonate catabolism, but neither verified nor characterized. These putative phosphonatases will be expressed using a wheat germ embryo-based cell-free protein production system, and biochemically characterized, using quantitative mass spectrometry (MS). The putative phosphonatases (phnases) implicated in phosphonate catabolism by this study and their metabolic products may reveal novel mechanisms of breakdown of this important subset of phosphate containing compounds. This NSF EAPSI award is funded in collaboration with the Japan Society for the Promotion of Science.