BIOSYNTHESIS OF ANTHRACYCLINE ANTIBIOTICS

我建议继续研究生物化学和遗传学 生产四烯霉素 C (Tcm C)，一种链霉菌的代谢产物 Glaucescens 化学分类为蒽环类药物，具有 中等抗肿瘤特性，作为次级代谢的模型。 可以使用有关聚酮化合物生物合成的信息，例如 Tcm C 增加已知药物的产量。 尝试制造新药 通过基因工程，这对蒽环类药物来说是一个有吸引力的前景 因为其中一些具有临床价值的抗肿瘤作用和显着的抗肿瘤作用 HIV 活性，聚酮化合物代表数百种的知识 不同的结构类型表明，这种结构的许多扰动 生物化学是可能的。 这可能会使新药的寻找 基因工程尤其卓有成效。 抗生素生产是链霉菌的一个特征 引起了相当大的关注。 探究其遗传学可能会 发现重要的新信息，因为次级代谢， 实验室缓慢生长（静止）阶段的独特特征 培养物，与快速生长细胞的初级代谢完全不同 这是大多数原核遗传学研究的焦点。 此外，使用 PKS 基因和调节基因的价值 抗生素生产以构建过度产生次生的菌株 代谢物已被证明；因此，有关监管的信息 机制应该在生物技术中具有广泛的用途。 我们未来五年的目标，按照优先顺序列出 将予以追究，具体如下。 1. 中药聚酮化合物的酶学研究 合酶（PKS）。 我们将通过以下方式研究聚酮化合物代谢的酶学： (i) 确定 tcm PKS 产生的酶的特性 基因，(ii) 使用这些酶开发生产系统 Tcm F2 和 Tcm F1（或 D3）体外试验，然后 (iii) 研究效果 用其他 PKS 的成分替代不同的酶 中医PKS。 这项工作可能会产生新的代谢物。 2. 监管 中医基因的表达。 我们将研究基因 通过 (i) 阐明 Tcm C 的转录组织来生产 Tcm C tcmIII/VI/Ia/II、tcmVII 和 tcmAR 基因，(ii) 确定是否 tcm PKS、tcmVII 和 tcmA 基因的表达受 tcmR 控制 基因或反之亦然，以及（iii）寻找基因或生理因素 控制 tcmIII/VI/Ia/II 和 tcmAR 基因的表达。 这将 提供对次生代谢调节的深入了解。 3. 性能 脂肪酸合酶（FAS）基因。 我们将确定效果 删除 S. glaucescens ACP-II 区域的 Orf1 基因对细胞生长的影响 中药C代谢物的开发和生产。 这部作品 将揭示聚酮化合物和脂肪酸之间可能的相互作用 代谢以及 Orf1 基因是否是 FAS 的一部分。

I propose to continue a study of the biochemistry and genetics of the production of tetracenomycin C (Tcm C), a metabolite of Streptomyces glaucescens that is classified chemically as an anthracycline and has moderate antitumor properties, as a model of secondary metabolism. Information about the biosynthesis of polyketides, like Tcm C, can be used to increase the production of known drugs. In attempts to make new drugs by genetic engineering, which is an attractive prospect for anthracyclines because some of them have clinically valuable antitumor and notable anti- HIV activity, the knowledge that the polyketides represent hundreds of different structural types suggests that numerous perturbations of this biochemistry are possible. This could make the search for new drugs by genetic engineering especially fruitful. Antibiotic production is a characteristic of Streptomyces that has attracted considerable attention. Probing its genetics is likely to uncover significantly new information because secondary metabolism, a unique characteristic of the slow growth (stationary) phase of laboratory cultures, is quite unlike the primary metabolism of rapidly growing cells that has been the focal point of most studies of prokaryotic genetics. Moreover, the value of using the PKS genes and genes that regulate antibiotic production to construct strains that overproduce secondary metabolites has been demonstrated; thus, information about the regulatory mechanisms should have wide-spread utility in biotechnology. Our goals for the next five years, listed in the priority in which they will be pursued, are as follows. 1. Enzymology of the tcm polyketide synthase (PKS). We will study the enzymology of polyketide metabolism by (i) determining the properties of the enzymes produced by the tcm PKS genes, (ii) using these enzymes to develop a system for the production of Tcm F2 nd Tcm F1 (or D3) in vitro, and then (iii) investigating the effect of substituting the components of other PKS's for the different enzymes of the tcm PKS. New metabolites may be produced in this work. 2. Regulation of the expression of the tcm genes. We will investigate the genetics of Tcm C production by (i) elucidating the transcriptional organization of the tcmIII/VI/Ia/II, tcmVII, and tcmAR genes, (ii) determining whether expression of the tcm PKS, tcmVII and tcmA genes is controlled by the tcmR gene or vice-versa, and (iii) searching for genes or physiological factors that control expression of the tcmIII/VI/Ia/II and tcmAR genes. This will provide insight into the regulation of secondary metabolism. 3. Properties of the fatty acid synthase (FAS) genes. We will determine the effect of deleting the Orf1 gene of the S. glaucescens ACP-II region on cell growth and development, and the production of the Tcm C metabolites. This work will reveal possible interactions between polyketide and fatty acid metabolism and whether the Orf1 gene is part of the FAS.