STRUCTURE AND FUNCTION OF UNIQUE NON-HEME IRON DIOXYGENASES

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 拟议的XAS实验是一个项目的一部分，旨在表征非血红素Fe（II）双加氧酶家族的两个成员的反应机制，AlkB同系物2（ABH 2，与纽约大学医学院Max Costa教授合作）和半胱氨酸双加氧酶（CDO）。具体来说，我们试图使用XAS来阐明Ni（II）离子抑制AlkB从而产生高甲基化DNA的机制，这反过来又会导致癌症并导致遗传缺陷。其次，我们试图了解的半胱氨酸和半胱胺在CDO的氧化还原化学中所发挥的作用。在ABH 2的情况下，XAS将提供一些关于顺序反应机制的信息（结合α-酮戊二酸，不结合，但改变铁的几何形状后，底物结合，和氧活化），这与类似的数据相比，从Ni（II）络合物将导致详细了解反应机制和机制，其中Ni（II）抑制酶。在CDO的情况下，半胱氨酸和半胱胺作为还原剂和/或配体的作用将得到解决。通过比较和对比这些酶的机制，我们希望进一步了解自然界如何调节非血红素Fe（II）酶的活性位点，以催化各种不同的反应，这是该酶家族的一个特征。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The proposed XAS experiments are part of a project aimed at characterizing the reaction mechanisms of two members of the nonheme Fe(II) dioxygenase family of enzymes, AlkB homologue 2 (ABH2, in collaboration with Prof. Max Costa, NYU School of Medicine) and cysteine dioxygenase (CDO). Specifically, we seek to use XAS to elucidate the mechanism by which Ni(II) ions inhibit AlkB and thus produce hypermethylated DNA, which in turn can cause cancer and lead to genetic defects. Second, we seek to understand the role played by cysteine and cysteamine in the redox chemistry of CDO. In the case of ABH2, XAS will provide some of the information regarding the sequential reaction mechanism (binding of a-ketoglutarate, not binding but change the iron geometry upon substrate binding, and oxygen activation) which in comparison with similar data from the Ni(II) complex will lead to a detailed understanding of the reaction mechanism and the mechanism by which Ni(II) inhibits the enzyme. In the case of CDO, the roles of cysteine and cysteamine as reductants and/or ligands will be addressed. By comparing and contrasting the mechanisms of these enzymes, we hope to further the understanding of how nature tunes the active sites of non-heme Fe(II) enzymes in order to catalyze the wide variety of different reactions that is a feature of this enzyme family.