Sulfate Adenylation-Biochemistry & Enzymology

硫酸腺苷酸化-生物化学

• 批准号: 7035271
• 负责人: Thomas S. Leyh
• 金额: $ 38.12万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-09-02 至 2008-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7035271
• 关键词: Mycobacterium tuberculosis; active sites; adenine nucleotides; adenosine triphosphate; allosteric site; aminoacid biosynthesis; aminoacid metabolism; biological signal transduction; chromatography; crystallization; cysteine; enzyme activity; enzyme complex; enzyme mechanism; enzyme structure; enzyme substrate complex; high energy compound; hydrolysis; mass spectrometry; nuclear magnetic resonance spectroscopy; nucleotidyltransferase; oxidoreductase; polymerase chain reaction; protein purification; sulfation; sulfite reductase

DESCRIPTION (provided by applicant): The entry of sulfate into metabolism requires that it be chemically activated. The only known metabolic means of activating sulfate is the formation of the very high-energy phosphoric-sulfuric acid anhydride bond (?Go= -19 kcal/mole). This bond is the chemical hallmark of activated sulfate (APS or PAPS), and it is from this high-energy environment that the sulfuryl-moiety (-SO3) passes quickly and favorably into its subsequent metabolic biochemistry. The activated bond is formed in a transfer reaction, catalyzed by ATP sulfurylase, in which the adenylyl-moiety (AMP~) of ATP is transferred to sulfate. In mammals, sulfuryl-group transfer to proteins and small molecule metabolites regulates a wide-variety of metabolic processes including neuropeptide- and steroid-hormone action, growth-factor recognition, and lymph cell circulation. This proposal outlines structurally-based mechanistic inquires designed to address central issues regarding the function and evolution of the mammalian class of ATP sulfurylases. Bacterial ATP sulfurylases harbor a GTPase subunit (discovered in this laboratory) that is an evolutionary descendant of elongation factor Tu. The conformational changes that this subunit undergoes as a consequence of GTP hydrolysis accelerate turnover of the adenylyl-transferase subunit, and couple the chemical potentials of GTP hydrolysis and APS synthesis. We have recently discovered that ATP sulfurylase forms a complex with another enzyme in the cysteine biosynthetic pathway (O-acetly-l-serine sulfhydrylase), and that their interactions produce "new" catalytic function - the hydrolysis of ATP. These enzymes organize into a metabolic pump, each stroke of which delivers one molecule of APS into the pathway. The mechanism of the pump will be explored in this grant. Working with an as yet uncharacterized and novel ATP sulfurylase from Mycobacterium tuberculosis, our preliminary data extends these finding to include five of the seven enzymes in the pathway. We will define and study the cysteine metabolon with the goal of understanding the hierarchical functions that emerge from the self-organization of this pathway.

描述（由申请人提供）： 硫酸盐进入代谢需要化学激活。激活硫酸盐的唯一已知代谢方法是形成非常高能量的磷酸硫酸赤二酸酐键（？GO = -19 kcal/mole）。该键是活化硫酸盐（APS或PAPS）的化学标志，正是从这种高能环境中，硫酸 - 硫酸 - SO3）迅速而有利地进入其随后的代谢生物化学。活化键是由ATP硫酶催化的转移反应形成的，其中ATP的腺苷酸（AMP〜）转移到硫酸盐。 在哺乳动物中，磺胺组转移到蛋白质和小分子代谢产物中调节包括神经肽和类固醇激素作用，生长因子识别和淋巴细胞循环在内的代谢过程的广泛不同。该提案概述了基于结构的机械询问，旨在解决有关哺乳动物类ATP硫酸盐类功能和演变的中心问题。 细菌ATP硫酸盐含有GTPase亚基（在该实验室发现），该亚基是伸长因子TU的进化后代。 由于GTP水解加速了腺苷 - 转移酶亚基的周转，因此该亚基发生的构象变化，并融入了GTP水解和APS合成的化学潜力。 我们最近发现，在半胱氨酸生物合成途径（o-乙烯 - 二甲硅硫丙烯酶）中，ATP硫化物与另一种酶形成复合物，并且它们的相互作用产生了“新的”催化功能 - ATP的水解。 这些酶组织成一个代谢泵，每个中风将一个AP分子输入途径。 该赠款将探索泵的机制。 我们的初步数据与结核分枝杆菌的尚未表征和新颖的ATP硫酸盐酶一起工作，将这些发现扩展到了途径中的七种酶中的五种。 我们将定义和研究半胱氨酸代谢剂，目的是了解从该途径的自组织中出现的层次函数。