A Biomimetic Approach to Elucidating the Role in Disease of the Oxygenase Enzyme Acireductone Dioxygenase (ARD)

项目摘要/摘要 酸性还原内酯双加氧酶(ARD)存在于动物体内普遍存在的蛋氨酸挽救途径(MSP)中， 植物和细菌。从酶学角度讲，它与SAM和MTA的调节有关；后者是 多胺合成和动物细胞生长的调节剂。这种酶能与铁和镍结合。 两种截然不同的产品。镍反应(“旁路”)催化酸性还原内酯转化为3- (甲硫基)丙酸、甲酸盐和一氧化碳，一种已知的抗凋亡信号分子。ARD是 唯一已知的金属酶的例子，其功能仅因金属离子的特性而不同。近期 哺乳动物的研究已经确定了该酶的小鼠(MmARD)和人类类似物(HsARD)的特征。在……里面 哺乳动物系统研究表明，ARD能够与锰和钴结合，从而发挥作用。 “途径”型化学。最近在体外研究中使用这些类似物的工作表明，HsARD可能 在脑肿瘤中发挥细胞内调节作用。此外，研究还表明，编码蛋白质的基因 HsARD，ADI1，在人和大鼠前列腺癌细胞以及胃癌和 纤维肉瘤细胞。这些兼职功能，以及ARD的酶作用，提出了这个问题 急性呼吸窘迫综合征与疾病之间的联系。到目前为止，关于这一机制的确切机制仍存在争议。 特定于区域的底物氧化，对金属特性在这种反应中所起的作用知之甚少。 该项目使用合成仿生模型来帮助回答这些问题。建议数 这项工作旨在极大地扩大使用镍和哺乳动物相关金属的ARD模型的可用性 有两个具体的目标：1.扩大有限的镍的仿生结构和功能模型的可用性。 ARD。这些将被用来检验观察到的“偏离路径”的结构和机械原因。 ARD的氧化区域选择性反应性。随后将进行机械和动力学研究，以提供有价值的 解释Ni-ARD中区域选择性底物激活机制的信息。2.合成并开始 利用与哺乳动物相关的金属(钴和钴)研究模型络合物的仿生反应性 特别是锰)。这些新化合物将有助于理解“偏离途径”。 反应和金属特性在促进人类细胞疾病中的作用。

Project Summary/Abstract Acireductone dioxygenase (ARD) is found in the ubiquitous methionine salvage pathway (MSP) in animals, plants, and bacteria. Enzymatically it is implicated in the regulation of SAM and MTA; the latter is a result of polyamine synthesis and a regulator of cell growth in animals. The enzyme can bind to iron and nickel giving two distinct products. The nickel reaction (“off-pathway”) catalyzes the transformation of acireductone into 3- (methylthio)propionate, formate and carbon monoxide, a known anti-apoptotic signaling molecule. ARD is the only known example of a metalloenzyme whose function differs only by the identity of the metal ion. Recent mammalian studies have characterized mouse (MmARD) and human analogues (HsARD) of the enzyme. In mammalian systems it has been shown that ARD is capable of binding manganese and cobalt to perform “off- pathway” type chemistry. Recent work with these analogues in in-vitro studies has shown that HsARD might play an intracellular regulatory role in brain tumors. Furthermore, it has been shown that the gene coding for HsARD, ADI1, is downregulated in human and rat prostate cancer cells as well as gastrocarcinoma and fibrosarcoma cells. These moonlighting functions, as well as the enzymatic roles of ARD beg the question about the connection between ARD in disease. To date there is still debate about the exact mechanism of the regiospecific substrate oxidation, and little is known about the role that metal identity plays in this reactivity. This project uses synthetic biomimetic modeling to contribute to answering these questions. The proposed work aims at greatly expanding the availability of models of ARD using nickel and mammalian relevant metals with two specific aims: 1. Expand the limited availability of biomimetic structural and functional models of Ni- ARD. These will be used to test the structural and mechanistic reasons for the observed “off-pathway” oxidative regioselective reactivity in ARD. Mechanistic and kinetic studies will follow to provide valuable information to explain the mechanism of regioselective substrate activation in Ni-ARD. 2. Synthesize and begin to study the biomimetic reactivity of model complexes using metals relevant to mammalian systems (cobalt and manganese specifically). These new compounds will contribute to the understanding of the “off-pathway” reactions and the role of metal identity in promoting disease in human cells.