Fungal Polyketide Synthases and Environmental Toxin Biosynthesis

真菌聚酮化合物合成与环境毒素生物合成

• 批准号: 8504225
• 负责人: CRAIG ARTHUR TOWNSEND
• 金额: $ 45.74万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1978
• 资助国家: 美国
• 起止时间: 1978-02-01 至 2018-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8504225
• 关键词: 3-hydroxybutanal; Accounting; Active Sites; Acyltransferase; Address; Affect; Aflatoxin B1; Aflatoxins; Agriculture; Amphotericin; Anabolism; Animals; Antibiotics; Behavior; Biochemical; Bioinformatics; Biological Factors; Biosynthetic Chemistry; Cancer Etiology; Carbon; Carboxylic Acids; Carcinogens; Catalysis; Catalytic Domain; Cereals; Cessation of life; Chemicals; Collaborations; Cyclization; Data; Daunorubicin; Dehydration; Diet; Dimerization; Discipline; Environmental Carcinogens; Enzymatic Biochemistry; Enzyme Gene; Enzymes; Epidemiology; Equilibrium; Erythromycin; Event; Exhibits; Exposure to; Family; Fatty-acid synthase; Food Supply; Fumonisins; Goals; Grant; Health; Hepatitis; Host Defense; Human; Individual; Infection; Investigation; Kinetics; Lead; Length; Libraries; Longevity; Lovastatin; Meat; Mediating; Melanins; Methods; Methylation; Methyltransferase; Milk; Monitor; Mono-S; Mutate; Mycotoxins; N-terminal; Nuts; Oxidoreductase; Pattern; Pharmacologic Substance; Plants; Play; Preparation; Property; Proteins; Ramp; Research; Risk Factors; Roentgen Rays; Role; Series; Sirolimus; Staging; Structural Models; Structure; Substrate Domain; System; Technology; Testing; Time; Toxic Environmental Substances; Toxic effect; Toxin; Type I DNA Topoisomerases; Variant; Virulence Factors; Water; Work; X-Ray Crystallography; Zearalenone; base; cercosporin; combinatorial; cost; crosslink; environmental toxicology; flexibility; fungus; human disease; inhibitor/antagonist; insight; plant poison; polyketide synthase; polymerization; programs; public health relevance; research study; synthetic biology; vigilance

DESCRIPTION (provided by applicant): In contrast to the toxic selectivity of some natural products that allow them to be used as antibiotics, fortuitous mainstays of human health and longevity, there are opposing, blunt toxicities by primitive mechanisms of action that overwhelm host defenses in preparation for systemic invasion. Fungi in particular can be pathogenic to animals and plants and use polyketide metabolites as virulence factors in these ways against their victims. Environmental toxins have detrimental effects on human health and must be closely monitored. That vigilance accounts for several $B/yr in losses to grain and nut crops and contaminated milk and meat destroyed. The aflatoxins are a paradigm among mycotoxins and occupy a central place in environmental toxicology. Hepatocarcinomas are the third most common cause of cancer death in the world. Hepatitis infections and dietary aflatoxin are major risk factors where clear epidemiological data correlate exposure to human disease. To the environmental carcinogen aflatoxin B1 can be added polyketide metabolites like T-2 toxin, zearalenone, fumonisin B, ochratoxin, patulin, citrinin and cercosporin. These secondary metabolites all derive from a family of fungal, polydomain enzymes called polyketide synthases (PKSs). They are fundamentally related to animal fatty acid synthases (FASs), but, unlike FASs, they synthesize reactive products that can undergo biosynthetic chemistry to a wide array of structural types. Many of the primitive toxins of pathogenic fungi arise from this versatile biosynthetic machinery. These enzymes have eluded investigation for years, especially compared to other types of PKSs, but the work of this lab in the last decade has made great inroads into this problem. These enzymes exhibit the unusual property of iterative catalysis where a small basis set of catalytic domains is reused multiple times but a fixed number of times to a specific, programmed end. This poorly understood catalytic behavior has been collectively called ¿programming¿ and is the goal of this research effort to understand. Great strides have been made in the current grant period with dramatic technical advances to dissect and reassemble functional domains for biochemical and structural analysis that we intend to drive the Research Plan proposed. A comprehensive approach is advanced to proceed on three fronts: protein X-ray crystallography of individual and multiple domains from the polyketide synthases, mechanistic enzymology of PKS function, and synthetic biology and combinatorial enzymology of a library of catalytic domains to elicit further understanding of function and to carry out syntheses of new products.

描述（由适用提供）：与某些天然产品的毒性选择性相反，这些产品可以用作抗生素，偶然的人类健康和寿命中的中流柱，具有原始作用机制具有相反的，钝性的毒性，这些机制使宿主防御的原始作用机制在准备系统入侵方面都淹没了。尤其是真菌对动物和植物可能是致病性的，并以这些方式使用聚酮化合物代谢物作为病毒因素，反对其出人意料，环境毒素对人类健康有害，必须密切监测。这种警惕性造成了几美元/年的损失，谷物和坚果作物以及被污染的牛奶和肉被破坏了。黄曲霉毒素是霉菌毒素中的范式，在环境毒理学中占据了中心地位。肝癌是世界上癌症死亡的第三大最常见原因。肝炎感染和饮食黄曲霉毒素是主要的危险因素，明确的流行病学数据与人类疾病的暴露相关。可以加入环境致癌物黄曲霉毒素B1，例如T-2毒素，Zearalenone，Fumonisin B，Ochratoxin，patulin，patulin，citrinin和Cercosporin，例如T-2毒素代谢物。这些次生代谢物均来自一个称为聚酮化合物合酶（PKSS）的真菌，多域酶。它们从根本上与动物脂肪酸合酶（FASS）有关，但是与FASS不同，它们合成可反应性产物，可以将生物合成化学与多种结构类型相关。病原真菌的许多原始毒素来自这种多功能的生物合成机制。这些酶已经避开了多年的投资，尤其是与其他类型的PKS相比，但是在过去十年中，该实验室的工作使这一问题大大融入了这一问题。这些酶表现出迭代催化的异常特性，其中一组较小的催化域被多次重复使用，但固定数量固定到特定的编程端。这种糟糕的理解催化行为被共同称为“编程”，这是这项研究工作的目标。在当前的赠款期间，已经取得了长足的进步，并进行了巨大的技术进步，以剖析和重新组装功能领域，以进行生化和结构分析，我们打算推动提出的研究计划。采取了一种全面的方法，可以在三个方面进行：从聚酮化合物合酶中的个体和多个结构域的蛋白质X射线晶体学，PKS功能的机械酶学以及合成生物学以及催化结构域库的合成生物学酶学，以引起对功能的进一步理解和进行新产品的合成。