BIOSYNTHESIS OF ANTHRACYCLINE ANTIBIOTICS

我建议继续进行生物化学和遗传学的研究。 链霉菌代谢产物四环素C的生产 在化学上被归类为一种蒽环类药物的蓝藻 温和的抗肿瘤特性，作为次生代谢的模型。 关于多酮生物合成的信息，如中药C，可以使用 以增加已知药物的产量。在尝试制造新药时 通过基因工程，这对蒽环类药物来说是一个诱人的前景 因为其中一些化合物具有临床应用价值和显著的抗肿瘤活性。 HIV的活性，知道聚酮代表数百个 不同的结构类型表明，这一点的许多扰动 生物化学是可能的。这可能会使寻找新药的工作 基因工程成果尤其丰硕。 产生抗生素是链霉菌的一个特征，它具有 引起了相当大的关注。探索它的遗传学很可能会 发现显著的新信息是因为次生代谢，一种 实验室缓慢生长(静止)阶段的独特特征 培养，与快速生长的细胞的初级新陈代谢非常不同 这一直是大多数原核遗传学研究的焦点。 此外，利用PKS基因和调控基因的价值 生产抗生素以构建第二次生产量过大的菌株 已经证明了代谢物；因此，关于调节的信息 机制应该在生物技术中具有广泛的实用价值。 我们未来五年的目标，列在它们的优先事项中 将被追查，如下所示。1.中药聚酮的酶学性质 合成酶(PKS)。我们将通过以下方法研究聚酮代谢的酶学 (I)测定中药PKS所产生的酶的性质 基因，(Ii)使用这些酶来开发一种生产 中药F2和中药F1(或D3)的体外培养，然后(III)观察其作用 用其他蛋白水解酶的成分代替不同的酶 中医药库。在这项工作中可能产生新的代谢物。2.规例 中医基因的表达。我们将研究人类的遗传学。 中药C的产生：(I)阐明其转录组织 TcmIII/VI/Ia/II、tcmVII和tcmAR基因，(Ii)确定 中药PKS、tcmVII和tcmA基因的表达受tcmR调控。 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基因表达的基因。这将是 洞察次级新陈代谢的调节。3.属性 脂肪酸合成酶(Fas)基因。我们将确定 灰斑链霉菌ACP-II区Orf1基因缺失对细胞生长的影响 以及中药C代谢物的生产。这部作品 将揭示聚酮和脂肪酸之间可能的相互作用 新陈代谢以及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.