X-RAY STRUCTURE STUDIES OF A TRANSCRIPTIONAL COACTIVATOR

描述：这项提案的长期目标是定义 蛋白质-蛋白质相互作用控制基因表达的机制。 DNA结合因子和RNA聚合酶之间架起了非共价桥 由最近发现的一类被称为辅活化子的蛋白质。钥匙 关于协同激活剂的问题包括：他们如何识别特定的 转录因子？它们对转录过程中的哪些步骤进行调控？多么 共激活剂是否受到监管？ 为了在分子水平上解决这些问题，本提案侧重于 肝细胞二聚化辅因子DCoH的X射线结构研究 核因子1(HNF-1)及其与HNF-1α的复合体。DCoH绑定 与DNA结合的HNF-1家族的二聚化结构域紧密结合， 肝脏特异的转录因子和增强200倍以上 HNF-1依赖基因的表达。DCoH还在以下环境中运行 缺乏HNF-1，提示存在更多的天主教蛋白质相互作用。此外, DCoH催化芳香族氨基的重要辅因子脱水 酸性羟基酶。为了调查两者之间的联系 DCoH的转录活性和酶活性及其活性的确定 在与HNF-1的相互作用中，Alber博士提出了以下具体目标：1. 结论1.提纯大鼠DCoH的高分辨X射线晶体结构。 DCoH与酶抑制剂络合物的结构测定 活性；3.确定二聚物的高分辨结构 HNF-1α的基序；以及4.确定HNF-1α的复合物的结构 HNF-1α二聚结构域和DCoH。 这些研究将对共激活剂的作用机制产生广泛的影响。 功能。因为基因调控在许多疾病中起着核心作用-- 包括出生缺陷、病毒感染和癌症--这项拟议的工作 对分子生物学和医学具有直接意义。

DESCRIPTION: The long term goal of this proposal is to define the mechanisms by which protein-protein interactions control gene expression. Noncovalent bridges between DNA-binding factors and RNA polymerases are made by a recently-discovered class of proteins called coactivators. Key questions about coactivators include: How do they recognize specific transcription factors? What steps in transcription do they regulate? How are coactivators regulated? To address these issues at the molecular level, this proposal focuses on x-ray structural studies of DCoH, the dimerization cofactor of hepatocyte nuclear factor 1 (HNF-1), and its complex with HNF-1alpha. DCoH binds tightly to the dimerization domain of the HNF-1 family of DNA-binding, liver-specific, transcription factors and enhances by over 200-fold expression from HNF-1-dependent genes. DCoH also functions in contexts that lack HNF-1, suggesting more catholic protein interactions. In addition, DCoH catalyzes the dehydration of an essential cofactor of aromatic amino acid hydroxylases. To investigate the connections between the transcriptional and enzymatic activities of DCoH and to define its interactions with HNF-1, Dr. Alber proposes the following specific aims: 1. Refine the high resolution x-ray crystal structure of rat DCoH; 2. Determine the structures of DCoH complexed with inhibitors of the enzyme activity; 3. Determine the high resolution structure of the dimerization motif of HNF-1alpha; and 4. Determine the structure of the complex of the HNF-1alpha dimerization domain and DCoH. These studies will have broad implications for the mechanisms of coactivator function. Because gene regulation plays a central role in many diseases-- including birth defects, viral infections and cancer--the proposed work has direct significance for molecular biology and medicine.