SPECIFICITY IN TERPENE AND STEROL BIOSYNTHESIS

萜烯和甾醇生物合成的特异性

• 批准号: 2629005
• 负责人: ROBERT M. COATES
• 金额: $ 27.27万
• 依托单位: UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
• 依托单位国家: 美国
• 财政年份: 1979
• 资助国家: 美国
• 起止时间: 1979-03-01 至 2002-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2629005
• 关键词: X ray crystallography; active sites; chemical models; chemical synthesis; enzyme complex; enzyme inhibitors; enzyme mechanism; enzyme substrate analog; isoprenoid; lipid biosynthesis; squalene; stable isotope; stereochemistry; steroid biosynthesis; sterols; terpenes

The major goal of this research program is to develop a fundamental understanding of the specificity, catalytic and control mechanisms, active site structures, and biological functions of key enzymes involved in terpene and sterol biosynthesis. Syntheses and applications of isotope-labelled substrates and intermediates, transition state-analog inhibitors, and related compounds are proposed to elucidate mechanistic aspects of the reactions, structures and conformations of intermediates, and 3-dimensional interactions in enzyme-substrate (or intermediate) analog complexes. Enzymatic experiments and X-ray diffraction analyses of the enzyme complexes will be carried out by collaborations with several biochemists and protein crystallographers. The stereochemistry and mechanistic characteristics of alkylations, cyclizations, and rearrangements catalyzed by squalene, taxadiene, abietadiene, epi-aristolochene, and vetispiradiene synthases as well as protein prenyl transferases will be elucidated to identify factors responsible for product specificity. Experiments with substrate analogs will probe active site tolerances, enable identification of enzyme-bound intermediates, and lead to novel isoprenoid products. Transition-state inhibitors as well as heavy-atom and other analogs of substrates and intermediates are proposed for use as active site and reaction pathway markers in X-ray crystallographic studies of isoprenoid synthases, or as photo-activatable agents for investigation of prenylated protein complexes. Fundamental knowledge concerning the substrate specificity, mechanisms, and catalytic functionality of enzymes such as epi-aristolochene, vetispiradiene, and taxadiene synthases may lead to more efficient production of the phytoalexins capsidiol and solavetivone for agricultural uses, or the chemotherapeutic agent taxol for cancer treatment, or lead to discovery of more active derivatives. High affinity inhibitors of squalene synthase have the potential to block cholesterol biosynthesis without deleterious side effects on the formation of other essential isoprenoid metabolites. Specific prenyl transferase inhibitors would have significant biochemical applications in the study of regulatory and signal-transducing proteins, as well as potential in cancer chemotherapy.

该研究计划的主要目标是开发一个基本的 了解特异性、催化和控制机制， 活性位点结构以及涉及的关键酶的生物学功能 萜烯和甾醇的生物合成。 的合成与应用 同位素标记底物和中间体，过渡态类似物 抑制剂和相关化合物被提议来阐明机制 中间体的反应、结构和构象方面， 以及酶-底物（或中间体）中的 3 维相互作用 模拟复合体。 酶实验和 X 射线衍射分析 酶复合物的开发将通过与 几位生物化学家和蛋白质晶体学家。 烷基化的立体化学和机理特征， 角鲨烯、紫杉二烯催化的环化和重排， abietadiene、表马兜铃烯 (epi-aristolochene) 和 vetispiradiene 合酶以及 将阐明蛋白质异戊烯基转移酶以确定因素 对产品的特殊性负责。 底物类似物的实验 将探测活性位点的耐受性，从而能够识别酶结合的 中间体，并产生新型类异戊二烯产品。过渡态 抑制剂以及重原子和其他底物类似物 建议将中间体用作活性位点和反应途径 类异戊二烯合酶 X 射线晶体学研究中的标记，或 作为研究异戊二烯化蛋白质的光活化剂 复合物。 有关底物特异性、机制的基础知识， 和酶的催化功能，例如表马兜铃烯， vetispiradiene和紫杉二烯合酶可能会导致更有效的 植物抗毒素辣椒二醇和索拉维酮的生产 农业用途，或癌症化疗剂紫杉醇 治疗，或导致发现更活性的衍生物。 高的 角鲨烯合酶的亲和力抑制剂有可能阻断 胆固醇的生物合成不会对身体产生有害的副作用 其他重要的类异戊二烯代谢物的形成。 特定异戊烯基 转移酶抑制剂将具有重要的生化应用 在调节和信号转导蛋白的研究中，以及 癌症化疗的潜力。