Overproduction of polyketide antimicrobials

描述(由申请人提供)：聚酮是一种不同类别的天然产品，具有既定的临床应用历史(例如红霉素、FK506、Iovastatin)。传统的菌种改良工艺对于使具有重要治疗价值的聚酮具有商业吸引力是必要的，但既耗时又繁琐。这项工作的长期目标是开发通用方法来解决聚酮类化合物的过度生产，然后将这些方法应用于新型聚酮类抗菌剂的产生。在这项提案中，我们的目标是生产新的红霉素类似物，用于先导生成和酮乐特和吗丁胺治疗药物的临床前开发。酮内酯是一类新的有效抗生素，对红霉素敏感生物具有抗菌活性。吗丁内斯是正在开发的胃动素受体激动剂，用于治疗胃肠道疾病、胃反流疾病和其他用途。这项建议的具体目标是：i.)使用第一阶段开发的红霉素高产系统表达几个转基因红霉素PKS基因，并生产早期和晚期测试所需的完全成熟的红霉素类似物，以及第二阶段。)使该系统适合于将合成的二酮-SNAC前体有效地整合到聚酮产品中，并通过前体定向的生物合成来产生红霉素类似物。作为具体目标III)，我们计划在广泛使用的放线菌宿主天蓝色链霉菌中启动第二代超产宿主的开发。这些目标将促进处于临床前开发晚期的酮内酯和吗丁内酯化合物的发展，潜在地为开发创造新的线索，并扩大可以通过在微生物系统中对聚酮合成酶进行遗传操作而实现的结构多样性。此外，建立定义明确的生产过剩宿主将有助于分析生产过剩的分子和生理基础。

DESCRIPTION (provided by applicant): Polyketides are a diverse class of natural products with an established history of clinical utility (e.g. erythromycin, FK506, Iovastatin). Conventional strain improvement processes are necessary to make therapeutically important polyketides commercially attractive but are time consuming and tedious. The long term goals of this work are to develop generic approaches to polyketide overproduction and then apply these approaches to the generation of novel polyketide antimicrobials. In this proposal, we are targeting the production of novel erythromycin analogs for lead generation and preclinical development of ketolide and motilide therapeutics. Ketolides are a new class of potent antibiotics with activity against erythromycin sensitive organisms. Motilides are motilin receptor agonists being developed for treatment of gastric pariesis, gastric reflux disease and other uses. The specific aims of this proposal are: i.) to use an erythromycin overproducing system developed in Phase I to express several genetically modified erythromycin PKS genes and produce fully mature erythromycin analogs needed for early and late stage testing, and ii.) to adapt the system to one that will efficiently incorporate synthetic diketide-SNAC precursors into the polyketide product and produce erythromycin analogs by precursor-directed biosynthesis. As specific aim iii), we plan to initiate development of a second generation generic overproduction host in the widely used actinomycete host Streptomyces coelicolor. These aims will facilitate the advancement of ketolide and motilide compounds that are in late stage preclinical development, potentially generate new leads for development, and expand the diversity of structures that can be achieved through the genetic manipulation of polyketide synthases in microbiological systems. Furthermore, the establishment of well-defined overproduction hosts will facilitate analyzing the molecular and physiological basis of overproduction.