BIOSYNTHESIS OF ANTITUBERCULAR NONRIBOSOMAL PEPTIDES

描述（由申请人提供）：结核病（TB）在世界范围内杀死的青壮年成年人比除艾滋病以外的任何其他疾病都多。此外，结核病是艾滋病毒/艾滋病感染者发病和死亡的主要原因。虽然结核病通常被认为是一种折磨最贫穷国家的疾病，但耐多药结核病病例的迅速增加及其向工业化国家的传播使这种疾病成为全球威胁。由于一级药物无效，必须使用更昂贵、通常效果更差、往往毒性更大的二线药物。因此，对新的抗结核药物的需求从未像现在这样大，然而，自上一种新型抗结核药物问世以来，已经过去了30多年。提高效力、降低毒性和缩短治疗时间的进展将对世界卫生和医疗保健费用产生巨大影响。本申请描述了一种获取、利用和操纵肽生物合成基因的方法，该基因指导前体构建和组装后剪裁，以创建新的抗结核肽。这些靶标是viomycin的类似物，viomycin是一种由链霉菌（Streptomyces vinaceus）产生的肽抗生素，也是一种二线抗结核药物，通常对耐多药结核病有效。Viomycin具有罕见的独特氨基酸，这些氨基酸对生物活性至关重要，但无法用于化学合成。该提案描述了导致这些新型氨基酸的生化转化的研究，包括在肽基载体（PCP）蛋白结合物种上发生的反应。研究人员提出了通过外源添加或原位形成的前体类似物进行靶向基因破坏和定向生物合成来产生新肽的实验。通过控制修饰和充分激活核心肽的酶也会形成新的化合物。成功地利用这些基因并破译与维霉素前体组装和裁剪有关的生化机制将产生有价值的信息，这些信息将被转化为产生新的抗结核药物的新分子工具。从这些研究中产生的知识和方法将直接适用于扩大其他生物活性肽家族的化学多样性。

DESCRIPTION (provided by applicant): Tuberculosis (TB) kills more young and middle-aged adults worldwide than any other disease with the exception of AIDS. Furthermore, TB is the leading cause of morbidity and mortality among the population living with HIV/AIDS. While TB is generally perceived as a disease afflicting the poorest countries, the rapid increase in cases of multidrug-resistant tuberculosis (MDR-TB) and its spread to industrialized nations makes the disease a global threat. As primary drugs are rendered ineffective, second-line agents that are more expensive, usually less effective and often more toxic must be used. Hence, the need for new anti-TB drugs has never been greater, yet it has been over 30 years since the introduction of the last novel antitubercular agent. Advances to improve potency, decrease toxicity, and shorten the duration of therapy would have an enormous impact on world health and healthcare costs. This application describes an approach to access, utilize and manipulate peptide biosynthesis genes that direct precursor construction and post-assembly tailoring to create novel antitubercular peptides. The targets are analogs of viomycin, a peptide antibiotic produced by Streptomyces vinaceus and a second-line antitubercular agent that is often effective against MDR-TB. Viomycin possesses rare and unique amino acids that are crucial for biological activity but are not available for chemical synthesis. The proposal describes studies on the biochemical transformations leading to these novel amino acids, including reactions proposed to occur on peptidyl carrier (PCP) protein-bound species. Experiments are proposed to generate new peptides through targeted gene disruption and directed biosynthesis with precursor analogs added exogenously or formed in situ. Novel compounds will also be formed by controlling enzymes that decorate and fully activate the core peptide. Successfully harnessing the genes and deciphering the biochemical mechanisms involved in viomycin precursor assembly and tailoring will yield valuable information that will be translated into novel molecular tools for generating new antitubercular agents. The knowledge and methods that arise from these studies will be directly applicable to expanding the chemical diversity in other families of bioactive peptides.