The Molecular Basis of Cellular Control Mechanisms

细胞控制机制的分子基础

• 批准号: 7555641
• 负责人: EVAN R KANTROWITZ
• 金额: $ 25.88万
• 依托单位: BOSTON COLLEGE
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-06-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7555641
• 关键词: Acceleration; Address; Affinity; Allosteric Regulation; Amino Acids; Antidiabetic Drugs; Antimalarials; Arts; Aspartate; Attention; Binding; Biological; Biological Process; Blood Glucose; Carbamoyl Transferases; Catalysis; Cells; Complex; Coupled; Crystallography; Data; Development; Diabetes Mellitus; Dihydroorotase; Enzymes; Evolution; Fluorescent Probes; Foundations; Fructose; Glucagon; Gluconeogenesis; Goals; Insulin; Ion Channel; Knowledge; Link; Malignant Neoplasms; Metabolic; Metabolic Control; Metabolic Pathway; Modeling; Molecular; Monitor; Motion; Movement; Nucleic Acid Precursors; Nucleic Acids; Nucleotide Biosynthesis; Pathway interactions; Pharmaceutical Preparations; Positioning Attribute; Process; Production; Protein Subunits; Proteins; Proteomics; Pyrimidine; Pyrimidine Nucleotides; Pyrimidines; Roentgen Rays; Signal Transduction; Signaling Molecule; Structure; System; Techniques; Time; X-Ray Crystallography; analog; base; biological systems; cell growth; cell growth regulation; cooperative study; design; diabetic; enzyme activity; inhibitor/antagonist; nucleotide metabolism; protein structure; reaction rate; receptor; transmission process

DESCRIPTION (provided by applicant): The long term objectives of this project are to elucidate the processes involved in the transmission of regulatory signals in biological systems, as a means toward understanding the molecular mechanisms of metabolic control. The understanding of how cells regulate and control all aspects of their function is vital for our ability to intervene when these control mechanisms break down. Almost all modes of signal transduction can be related in some manner to protein conformational changes. For example, the conformational changes induced by the binding of insulin or glucagon to their receptors modulate blood sugar levels, or the large quaternary conformational changes of allosteric enzymes regulate metabolic pathways by altering their catalytic activity. During this project period we will concentrate on three systems involved in signal transmission and allosteric control. The allosteric enzymes aspartate transcarbamoylase (ATCase) and fructose 1,6- bisphosphatase (FBPase) are involved in controlling the rates of the pyrimidine and gluconeogenesis pathways, respectively. Both of these enzymes undergo dramatic conformational changes involving loop motions and movements of entire protein subunits for their function. In addition, we will study the cooperative enzyme, dihydroorotase. This enzyme in pyrimidine nucleotide biosynthesis undergoes loop motions that are coordinated with catalytic activity. A variety of approaches will be used to acquire a molecular-level understanding of how these enzymes function. This project directly addresses fundamental questions of how biological signals are transmitted, in general, and how allosteric regulation controls enzymatic activity, in particular. The specific aims of this application are divided into fundamental and practical components. We will use state of the art techniques involving time-resolved small-angle X-ray scattering and time-resolved X-ray crystallography to capture the details of the effects that signaling molecules have on these enzymatic systems at the atomic level. We will also use strategically placed fluorescent probes in these enzymes, both to monitor the conformational changes and to relate these conformational changes to their function. We will use X-ray crystallography to define each step in the catalytic and allosteric mechanisms of ATCase, including at the moment of bond formation. We will also use these structural data to design highly potent inhibitors of ATCase and FBPase that may be used for the development of new anti-proliferation, anti-malarial and anti-diabetic agents. Understanding of the relationship between conformational changes and allosteric control in these proteins will also help us elucidate the molecular basis of cellular control mechanisms. The understanding of the atomic level details of the transmission of regulatory signals, which control most biological processes, is critical for our ability to intervene when these controls break down. This application will concentrate on transmission of regulatory signals in enzymes involved in the pathway that produces the precursors of the nucleic acids, and of one of the pathways involved in maintaining blood sugar levels. A molecular level understanding of how these enzymes exert control over their respective pathway will provide a basis for the rational development of new anti-cancer, anti-diabetic and anti-malarial drugs.

描述（由申请人提供）：该项目的长期目标是阐明在生物系统中调节信号传输所涉及的过程，以理解代谢控制的分子机制的一种手段。对细胞如何调节其功能各个方面的理解对于当这些控制机制分解时我们干预的能力至关重要。几乎所有信号转导模式都可以与蛋白质构象变化相关。例如，胰岛素或胰高血糖素与受体的结合引起的构象变化调节血糖水平，或者，变构酶的大四元素构象变化通过改变其催化活性来调节代谢途径。在此项目期间，我们将集中于涉及信号传输和变构控制的三个系统。天冬氨酸经钙甲酰胺酶（ATCASE）和果糖1,6-双磷酸酶（FBPase）分别参与控制嘧啶和糖异生途径的速率。这两种酶都经历了巨大的构象变化，涉及整个蛋白质亚基的循环运动和运动的运动。此外，我们将研究合作酶，二氢酶。嘧啶核苷酸生物合成中的这种酶经历了与催化活性协调的环运动。各种方法将用于获取对这些酶如何发挥作用的分子级别的理解。该项目直接解决了有关生物信号如何传播的基本问题，以及变构调节如何控制酶活性。本应用的具体目的分为基本和实用的组成部分。我们将使用涉及时间分辨的小角度X射线散射和时间分辨X射线晶体学的最先进技术来捕获信号分子对原子水平上这些酶促系统的影响的细节。我们还将在这些酶中使用策略性地放置的荧光探针来监测构象变化，并将这些构象变化与其功能相关联。我们将使用X射线晶体学来定义ATCASE的催化和变构机理中的每个步骤，包括在键形成时。我们还将使用这些结构数据来设计ATCASE和FBPase的高效抑制剂，这些抑制剂可用于开发新的抗增殖，抗癌症和抗糖尿病药物。了解这些蛋白质中构象变化和变构控制之间的关系也将有助于我们阐明细胞控制机制的分子基础。 控制大多数生物学过程的调节信号传播的原子级别细节对于我们在这些控制分解时干预的能力至关重要。该应用将集中于在产生核酸前体的酶中的调节信号的传播，以及与维持血糖水平有关的途径之一。对这些酶如何对其各自途径产生控制的分子水平将为新的抗癌，抗糖尿病和抗癌症药物的合理发展提供基础。