Sulfotransferase Specificity and the Development of Sulfation Resistant Compounds

磺基转移酶特异性和抗硫酸化化合物的开发

• 批准号: 9199281
• 负责人: Thomas S. Leyh
• 金额: $ 30.34万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE, INC
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-01 至 2017-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9199281
• 关键词: Sulfotransferase; Specificity; Development; Sulfation; Resistant

DESCRIPTION (provided by applicant): The objective of this proposal is to obtain a deep and fundamental understanding of the molecular behavior of the human cytosolic sulfotransferases. This 13-member enzyme family regulates the receptor interactions of hundreds of small molecules by transferring the sulfuryl-group (-SO3) from a nucleotide donor (PAPS, 3'-phosphoadenosine 5'-phosphosulfate) to the hydroxyl- or amine-moieties of small-molecule acceptors. Understanding the molecular interactions between SULTs and their substrates and allosteric modulators will substantially deepen our understanding of the roles of these enzymes in biology and provide a means of controlling SULT activity in-vivo. Aim I. We have discovered that SULT1A1 uses positive synergy to enhance the catalytic efficiencies of select substrates 103-104-fold. This is the first example of positive synergy in the SULT field. The molecular basis of these stunning catalytic enhancements will be determined, and the substrate features that elicit positive synergy will be identified with the goal of understanding how SULT-substrate reactivity is controlled. Aim II focuses on an important and virtually unexplored area in sulfur metabolism - the allosteric regulation of SULT function. The literature describes a small number of important drugs and nutrients (aspirin, Celebrex (r), Ponstel (r) and epigallocatechin gallate - which comprises ~ 12% of the mass of dry tea leaves) that regulate SULTs by binding at sites separate from those of substrates. Binding is tight, isozyme specific and physiologically relevant. Certain compounds inhibit while others change the specificity and activate turnover of the enzyme. We will determine the first allostere-bound SULT structures - the crystals needed to do this are in-hand. Seeing these ligand-bound allosteric pockets at atomic resolution will change our perceptions of SULT metabolism and provide novel opportunities to control SULT activity. Aim III. Hundreds of FDA-approved drugs are inactivated by sulfation. Preventing this modification is expected to increase the concentration and half-lives of the active forms of these compounds in-vivo. Classical inhibition strategies are detrimental because they prevent essential SULT functions. Consequently, no means of achieving this end is described in the literature. Our recent insights into the molecular basis of SULT-substrate selectivity lay the foundations for a novel strategy to prevent sulfation without inhibiting SULTs or altering a compound's receptor-binding affinity. We will develop this strategy and demonstrate its therapeutic potential. Sidechains that prevent sulfation will be identified and inserted into two FDA-approved drugs whose bioactivities are potently suppressed by sulfation: apomorphine, used to treat late-stage Parkinson Disease, and ethinyl estradiol, the active estrogen in most oral contraceptives. The receptor affinities of these new compounds will be tested in mammalian cells and their metabolism will be evaluated using primary human hepatocytes.

描述（由申请人提供）：本提案的目的是对人胞质磺基转移酶的分子行为进行深入和基本的了解。这个13个成员的酶家族通过将硫酰基（-SO 3）从核苷酸供体（PAPS，3 '-磷酸腺苷5'-磷酸硫酸酯）转移到小分子受体的羟基或胺部分来调节数百种小分子的受体相互作用。了解SULT与其底物和变构调节剂之间的分子相互作用将大大加深我们对这些酶在生物学中的作用的理解，并提供一种在体内控制SULT活性的方法。艾姆岛我们已经发现，SULT 1A 1利用正协同作用将选择底物的催化效率提高103-104倍。这是SULT领域积极协同作用的第一个例子。这些惊人的催化增强的分子基础将被确定，和基板功能，引起积极的协同作用将被确定与了解如何SULT基板反应性控制的目标。目的II关注硫代谢中一个重要的和实际上未探索的领域-SULT功能的变构调节。文献描述了少数重要的药物和营养素（阿司匹林、西乐葆（r）、Ponstel（r）和表没食子儿茶素没食子酸酯）， 其包含干茶叶质量的~ 12%），其通过在与底物的位点分开的位点处结合来调节SULT。结合紧密，同工酶特异性和生理相关。某些化合物抑制，而另一些则改变特异性并激活酶的周转。我们将确定第一个变构结合的SULT结构-需要这样做的晶体是在手。在原子分辨率下看到这些配体结合的变构口袋将改变我们对SULT代谢的看法，并提供控制SULT活性的新机会。Aim III.数百种FDA批准的药物都是通过硫酸化灭活的。预期防止这种修饰会增加这些化合物的活性形式在体内的浓度和半衰期。经典的抑制策略是有害的，因为它们阻止了基本的SULT功能。因此，文献中没有描述实现这一目的的手段。我们最近对SULT-底物选择性的分子基础的见解为一种新的策略奠定了基础，以防止硫酸化，而不抑制SULT或改变化合物的受体结合亲和力。我们将开发这种策略并展示其治疗潜力。防止硫酸化的侧链将被识别并插入到两种FDA批准的药物中，这些药物的生物活性被硫酸化有效抑制：阿扑吗啡，用于治疗晚期帕金森病，乙炔雌二醇，大多数口服避孕药中的活性雌激素。将在哺乳动物细胞中检测这些新化合物的受体亲和力，并使用原代人肝细胞评价其代谢。