Synthetic Biology Approach to Regioselectively Modified Polyketides

区域选择性改性聚酮化合物的合成生物学方法

• 批准号: 8677902
• 负责人: Gavin J Williams
• 金额: $ 27.42万
• 依托单位: NORTH CAROLINA STATE UNIVERSITY RALEIGH
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-06-15 至 2018-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8677902
• 关键词: Acyl Carrier Protein; Acyl Coenzyme A; Acyltransferase; Address; Anabolism; Biochemical; Biological; Biological Factors; Carbon; Catalysis; Cells; Chemical Structure; Chemicals; Coenzyme A; Coenzyme A Ligases; Complex; Coupled; Data; Engineering; Enzymes; Generations; Goals; In Vitro; Lead; Ligase; Literature; Malonates; Malonyl Coenzyme A; Medicine; Molecular; Organic Synthesis; Outcome; Pathway interactions; Permeability; Pharmaceutical Preparations; Physical condensation; Positioning Attribute; Production; Public Health; Reaction; Research; Role; Route; Specificity; Staging; Structure; Substrate Specificity; System; Therapeutic; Vertebral column; analog; base; carboxylation; combinatorial; design; drug discovery; genetic manipulation; improved; in vivo; mutant; novel; novel strategies; phosphopantetheinyl transferase; polyketide synthase; prototype; public health relevance; small molecule; synthetic biology; thioester

DESCRIPTION (provided by applicant): The broad and potent biological activities of polyketides are determined by their chemical structures, which are constructed by polyketide synthases (PKSs). Combinatorial biosynthesis approaches aimed at creating designer PKSs for the generation of polyketide analogues have been limited in terms of scope and efficiency due to the requirement to provide tailored biosynthetic pathways for the generation and installation of non-natural extender units into polyketides. As part of our long term goal of reprogramming the biosynthesis of natural products for the synthesis of potential drugs, the overall objective here is to use tailor-made enzymes to build an artificial biosynthetic pathway for the synthesis and installation of diverse extender units into polyketides. Our hypotheses are (1) a promiscuous acyl-CoA synthetase can be created and used to synthesize diverse extender units, (2) novel non-natural substrates for PKSs and trans-ATs can be identified by probing the specificity of these enzymes with diverse extender units, and (3) inherent promiscuity of PKSs and/or inherent/engineered promiscuity of trans-ATs can be harnessed to construct prototype bacterial strains for regioselective installation of non-natural extender units into polyketides. These hypotheses are supported by (1) strong preliminary data that shows the substrate specificity of a malonyl-CoA synthetase can be expanded, (2) preliminary data and literature precedent that hint at potential promiscuity of PKSs and trans-ATs, and (3) the ability to produce natural polyketides in heterologous hosts and the known cell permeability of required small molecule precursors. The rationale for the proposed research is that our proposed acyl-CoA synthetase/trans-AT route offers the ability to produce a broad variety of extender units in vivo and in vitro, enabling identification of new PKS specificities, and ultimately the synthesis of regioselectively modified polyketides. The following specific aims will be completed (1) create promiscuous acyl-CoA synthetases for extender unit generation, (2) characterize and alter the specificity of PKSs and related biosynthetic machinery, and (3) construct prototype bacterial strains for extender unit generation and installation into polyketides. The expected outcomes of the proposed research include (1) mutant enzymes for PKS substrate synthesis, (2) novel specificities for PKSs and related machinery, (3) bacterial strains for heterologous production of polyketide analogues, and (4) improved understanding of substrate specificity and catalysis in PKSs. The results are expected to have broad positive impact and lead to vertical advances in natural product synthesis, synthetic biology, and drug discovery by (1) providing new strategies for natural product diversification, (2) extending our understanding of PKS catalyzed reactions, (3) providing new approaches for engineering PKSs and other enzymes, and (4) access to biologically active natural products not readily accessible by conventional organic synthesis or genetic manipulation.

描述（由申请人提供）：聚酮化合物广泛而有效的生物活性由其化学结构决定，这些化学结构由聚酮化合物合酶（PKS）构建。由于需要提供定制的生物合成途径来生成非天然延伸单元并将其安装到聚酮化合物中，旨在创建用于生成聚酮化合物类似物的设计PKS的组合生物合成方法在范围和效率方面受到限制。作为我们重新编程天然产物生物合成以合成潜在药物的长期目标的一部分，这里的总体目标是使用定制的酶来构建人工生物合成途径，用于合成不同的延伸单元并将其安装到聚酮化合物中。我们的假设是（1）可以创建混杂的酰基辅酶A合成酶并用于合成不同的延伸剂单元，（2）可以通过用不同的延伸剂探测这些酶的特异性来鉴定PKS和反式AT的新型非天然底物单位，以及（3）可以利用 PKS 的固有混杂性和/或反式 AT 的固有/工程混杂性来构建用于区域选择性安装的原型细菌菌株将非天然增量单元转化为聚酮化合物。这些假设得到以下支持：(1) 强有力的初步数据表明丙二酰辅酶 A 合成酶的底物特异性可以扩展，(2) 初步数据和文献先例暗示 PKS 和反式 AT 的潜在混杂，以及 (3)在异源宿主中产生天然聚酮化合物的能力以及所需小分子前体的已知细胞渗透性。拟议研究的基本原理是，我们提出的酰基辅酶A合成酶/反式AT途径提供了在体内和体外产生多种延伸单元的能力，从而能够识别新的PKS特异性，并最终合成区域选择性修饰的聚酮化合物。将完成以下具体目标（1）创建用于扩展单元生成的混杂酰基辅酶A合成酶，（2）表征和改变PKS和相关生物合成机器的特异性，以及（3）构建用于扩展单元生成和安装的原型细菌菌株成聚酮化合物。拟议研究的预期成果包括（1）用于 PKS 底物合成的突变酶，（2）PKS 和相关机制的新特异性，（3）用于异源生产聚酮化合物类似物的细菌菌株，以及（4）提高对底物特异性的理解以及 PKS 中的催化作用。研究结果预计将产生广泛的积极影响，并通过（1）为天然产物多样化提供新策略，（2）扩展我们对 PKS 催化反应的理解，（3 ）提供了设计PKS和其他酶的新方法，以及（4）获得传统有机合成或基因操作无法轻易获得的生物活性天然产物。