PROTEIN TYROSINE PHOSPHATASES STRUCTURE/FUNCTION

蛋白酪氨酸磷酸酶（PTPases）和双特异性 磷酸酶共享氨基酸序列同一性，然而这两个家族 蛋白质具有不同的底物特异性。PTPases将 从含磷酸-Tyr的蛋白质中水解磷酸， 特异性磷酸酶将从磷酸-Ser/Thr水解磷酸， 含磷酸-Tyr的底物。这两个酶家族是 在各种催化剂中具有重要作用的显着催化剂， 生物过程。PTPases似乎调节 受体如胰岛素和血小板衍生生长因子 受体的已证明细菌PTD 1是一种毒力决定因子 导致瘟疫和黑死病的致病菌 双重特异性磷酸酶包括细胞周期调节剂cdc 25， 其功能是使CDC 2去磷酸化。这个催化剂家族 在细胞生长和细胞分裂中起重要作用。双重特异性 磷酸酶也存在于病原性病毒中，例如牛痘病毒， 以及天花病毒。 本提案中概述的目标之一是了解 以及PTODN的功能。我们将使用动力学和机械研究 再加上X射线结构（正在进行中）， 这些蛋白质的催化机制的全貌。的 不变酸性残基（Asp，Glu）的催化性质，以及 将检查所有PTPases中存在的不变Arg残基。目标 是定义它们在底物结合和/或催化中的作用。我们将 还可以确定细菌和哺乳动物的PTPases是否使用共同的 催化战略双特异性磷酸酶的研究将成为焦点 大量获得这个家庭的一名成员用于结构 和功能研究（我们针对的双重特异性磷酸酶 在这些研究中是牛痘H1相关磷酸酶; VHR）。努力将 旨在获得适合于X射线结构的晶体 保持战略定力这些信息可能会导致更大的 了解整个二元催化剂家族的催化性能 特异性磷酸酶。

The protein tyrosine phosphatases (PTPases) and the dual specific phosphatases share amino acid sequence identity, however the two families of proteins have distinct substrate specificities. The PTPases will hydrolyze phosphate from phospho-Tyr containing proteins while the dual specific phosphatases will hydrolyze phosphate from phospho-Ser/Thr and phospho-Tyr containing substrates. These two enzyme families are remarkable catalysts which have important roles in a variety of biological processes. The PTPases appear to regulate the activities of receptors such as insulin and the platelet-derived growth factor receptor. A bacterial PTPase has been shown to be a virulence determinant in the pathogenic bacteria responsible for the Plague or the Black death. The dual specific phosphatases include the cell cycle regulator, cdc25, which functions to dephosphorylate cdc2. This family of catalysts play important roles in cell growth and cell division. The dual specific phosphatases are also present in pathogenic viruses, such as vaccinia as well as in smallpox virus. One of the goals outlined in this proposal is to understand the structure and function of the PTPase. We will use kinetic, and mechanistic studies coupled with an X-ray structure (which is in progress) to develop a more complete picture of the catalytic mechanism of these proteins. The catalytic properties of invariant acidic residues (Asp, Glu), as well as invariant Arg residues present in all PTPases, will be examined. The goal is to define their role(s) in substrate binding and/or catalysis. We will also determine if the bacterial and mammalian PTPases use a common catalytic strategy. Studies on the dual specific phosphatases will focus on obtaining one member of this family in large quantities for structural and functional studies (the dual specific phosphatase we have targeted in these studies is Vaccinia H 1 Related phosphatase; VHR). Efforts will be directed at obtaining crystals suitable for an X-ray structure determination. This information will likely lead to a greater understanding of the catalytic properties of the entire family of dual specific phosphatases.