Enzymatic Cyclization to Labdanes and Related Diterpenoid Natural Products

酶促环化生成拉丹烷类及相关二萜类天然产物

• 批准号: 7491396
• 负责人: REUBEN JOHN PETERS
• 金额: $ 2万
• 依托单位: IOWA STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7491396
• 关键词: Acids; Active Sites; Alkenes; Anabolism; Anti-Inflammatory Agents; Anti-inflammatory; Antibiotics; Antimicrobial Effect; Applications Grants; Area; Biochemistry; Biological; Biological Factors; C-terminal; Catalysis; Chemical Structure; Chemicals; Class; Classification; Cloning; Collaborations; Complex; Coupled; Crystallography; Cyclization; DNA Sequence Rearrangement; Diphosphates; Diterpenes; Drug Industry; Elements; Engineering; Environment; Enzymatic Biochemistry; Enzymes; Escherichia coli; Exhibits; Family; Figs - dietary; Foundations; Future; Goals; Heterogeneity; Hydrocarbons; Illinois; Individual; Investigation; Isomerism; Knowledge; Labdanes; Libraries; Mediating; Medical; Metabolic; Metabolic Pathway; Metabolism; Minor; Modeling; Modification; Molecular Conformation; N-terminal; Numbers; Outcome; Pathway interactions; Pennsylvania; Pharmacologic Substance; Phytochemical; Plants; Principal Investigator; Production; Publishing; Purpose; Range; Reaction; Refractory; Relative (related person); Research; Research Personnel; Site; Site-Directed Mutagenesis; Skeletal system; Source; Specific qualifier value; Specificity; Structure; Structure-Activity Relationship; Substrate Specificity; System; Terpenes; Testing; Triterpenes; Vertebral column; Work; analog; anticancer activity; base; combinatorial; copalyl diphosphate; ent-kaurene synthetase A; experience; geranylgeranyl diphosphate; improved; innovation; insight; interest; ionization; isoprenoid; labdane; member; novel; pimara-7,15-diene; prenyl; programs; protonation; terpene synthase

Labdanes and related diterpenoids form a large group of almost 7,000 organic compounds that display a wide range of biological activity and includes a number with significant pharmaceutical activity, particularly medically relevant anticancer, anti-inflammatory, or antimicrobial effects. In addition, potential uses for many of these generally scarce natural products have yet to be fully explored. Biosynthesis of these complex compounds is initiated via a poorly understood acid/base catalyzed (class II) reaction, which forms the bicyclic core structure that defines this super-family of natural products. This bicyclic core is then specifically elaborated by a more typical allylic diphosphate ionization driven (class I) reaction. Interestingly, these mechanistically distinct reactions are mediated by phylogenetically related terpene synthases, albeit in different active sites. Despite the functional importance of the two classes of labdane-related diterpene synthases in initiating the biosynthesis of large numbers of natural products with both realized and potential medical significance, little is known about the enzymatic determinants underlying substrate and product specificity. We propose to investigate these consecutive cyclization reactions as a first step towards our long-term goal of engineering terpenoid natural product biosynthesis for pharmaceutical purposes. On the basis of our previously published and preliminary studies, we hypothesize that the class I active site resides in the C-terminal domain, while the class II active site lies at the interface between two other domains. The structurally defined C-terminal domain associated with class I reactions enables immediate study of the observed specificity via macromolecular modeling directed mutational analysis. To characterize class II cyclization more basic mechanistic enzymology studies are proposed to identify the determinants for catalysis, as well as initial investigations of product specificity. In addition, for both classes of reactions we expect to obtain significant insights through collaborative experimental structure determination, and via continued identification of functionally novel enzymes, along with initial metabolic engineering studies. Thus, the proposed studies will elucidate the structure-function relationships underlying the consecutive class II/class I cyclization reactions in labdane-related diterpene biosynthesis, andwill have a broader impact in further increasing our understanding and use of terpenoid enzymatic cyclization more generally.

Labdanes和相关的二萜类化合物组成了一个由近7000种有机化合物组成的大群体