The biosynthesis of N-N bond-containing natural products

项目摘要 微生物天然产物具有复杂的化学结构和强大的生物活性，是一类重要的微生物天然产物。 毒品的重要来源。虽然这些分子几十年来一直吸引着合成和药物化学家， 最近，构建天然产物支架的潜在生物合成途径已经被 被认为是新酶的重要储存库。发现新的酶化学和生物合成 战略扩展了我们对自然合成能力的基本理解。这也是关键的第一步 这一基础知识的应用，可以作为一个灵感的合成化学家。很长的- 这项研究的长期目标是确定微生物酶，这些酶催化以前未被认识到的 化学转化我们设想通过研究天然的生物合成来发现这样的酶。 含有重要分子结构和未知生物合成来源的官能团的产品。一个 此类结构基序的重要类别是含有氮-氮（N-N）键的官能团、 在200种最畅销的药物中，有9%的药物含有化学键。含反应性N-N键的官能团， 包括重氮基和N-亚硝基，是生物活性小分子的关键部分， 链脲佐菌素（Zanosar®），一种临床上用于治疗转移性胰腺癌的药物。它们也是独一无二的 使化学试剂，与重氮化合物介导许多重要的和强大的化学 在合成化学、生物催化和双正交化学中的转化。虽然反应性N-N键 存在于微生物天然产物中，但其生物合成来源知之甚少。因此， 本申请的目的是发现和表征构建重氮-和N-亚硝基-的酶， 含有代谢物。我们实验室和其他实验室的初步结果揭示了生物合成基因簇 负责构建多种含重氮和N-亚硝基的天然产物，包括链脲霉素 和其他已经在临床试验中的分子。这些发现为我们的三个互补性研究奠定了基础。 具体目标：1）鉴定和表征负责构建重氮基团的生物合成酶 对天然产物Cremeomycin和Kinamycin的生物合成酶进行了鉴定和表征 负责构建天然产物链脲佐菌素和丙氨酸核苷的N-亚硝基; 3）获取 另外的重氮和N-亚硝基生物合成酶和天然产物，通过表征隐藏基因簇。 通过利用基因组时代微生物天然产物的巨大结构多样性， 发现和表征生物合成转化，填补我们目前对酶的认识的关键空白 化学能力。最后，我们制定了研究反应性N- 含N键的官能团也将容易地推广到在本文中发现的另外的结构基序。 微生物天然产物

PROJECT SUMMARY Microbial natural products possess complex chemical structures as well as potent biological activity and are an important source of drugs. While these molecules have captivated synthetic and medicinal chemists for decades, more recently the underlying biosynthetic pathways that construct natural product scaffolds have been recognized as important reservoirs of novel enzymes. Uncovering new enzymatic chemistry and biosynthetic strategies expands our basic understanding of Nature’s synthetic capabilities. It is also a critical first step toward applications of this fundamental knowledge and can serve as an inspiration for synthetic chemists. The long- term goal of the proposed research is to identify microbial enzymes that catalyze previously unappreciated chemical transformations. We envision discovering such enzymes by studying the biosynthesis of natural products containing important molecular architecture and functional groups of unknown biosynthetic origin. An important class of such structural motifs are functional groups containing a nitrogen-nitrogen (N–N) bond, a chemical linkage found in 9% of the 200 best-selling drugs. Reactive N–N bond-containing functional groups, including diazo and N-nitroso groups, are a critical part of biologically active small molecules including streptozotocin (Zanosar®), a clinically used treatment for metastatic pancreatic cancer. They are also uniquely enabling chemical reagents, with diazo compounds mediating many important and powerful chemical transformations in synthetic chemistry, biocatalysis, and biorthogonal chemistry. Though reactive N–N bonds are present in microbial natural products, their biosynthetic origins are poorly understood. Thus, the overall objective of this application is to discover and characterize enzymes that construct diazo- and N-nitroso- containing metabolites. Preliminary results from our lab and others have uncovered biosynthetic gene clusters responsible for constructing multiple diazo- and N-nitroso-containing natural products, including streptozotocin and other molecules that have been in clinical trials. These findings set the stage for our three complementary specific aims: 1) identify and characterize the biosynthetic enzymes responsible for constructing the diazo groups of the natural products cremeomycin and kinamycin; 2) identify and characterize the biosynthetic enzymes responsible for constructing the N-nitroso groups of the natural products streptozotocin and alanosine; 3) access additional diazo and N-nitroso biosynthetic enzymes and natural products by characterizing cryptic gene clusters. By leveraging the tremendous structural diversity of microbial natural products in the genomic era, we will rapidly discover and characterize biosynthetic transformations that fill critical gaps in our current knowledge of enzymatic chemistry capabilities. Finally, the workflow we have formulated for investigating the biosynthesis of reactive N– N bond-containing functional groups will also be readily generalizable to additional structural motifs found in microbial natural products.