PHOSPHONIC ACID BIOSYNTHETIC PATHWAYS

在之前的资助期内，我们的酶学和合成化学研究补充了遗传和生化方面的努力，以了解天然产物磷酸盐的生物合成逻辑。该项目团队已经取得了重大进展，开发了有效的方法来检测新的膦酸盐生物合成基因簇，并非常详细地了解了导致商业上重要的膦酸盐（如磷丙氨酸和磷霉素）的生物合成途径。随着遗传和生化研究效率的提高，一个新的瓶颈被发现，即涉及低效的纯化策略，从而减缓了新发现的基因簇产物的结构解析。本子项目拟开展的部分研究将集中于开发这些新化合物的高效纯化和结构解析方法。此外，过去拨款期间的基因组测序工作确定了在不同生物体中通过非常不同的生物合成途径产生相同天然产物的情况。我们将研究这些趋同进化的例子。最后，许多天然产物膦酸盐作为短肽产生，以促进肽渗透物在目标生物中的吸收。然而对于一些化合物，小的非核糖体肽合成酶（NRPS）簇负责肽键的形成，许多含膦酸盐的肽以不同的，通常未知的方式组装。我们将尝试对这个非常重要的方面提供更多的见解，以考虑到未来可能的工程努力。

In the previous grant period, our enzymology and synthetic chemistry studies complemented the genetic and biochemical efforts towards understanding the biosynthetic logic of natural product phosphonates. The program project team has made significant progress, developing effective methods to detect new phosphonate biosynthetic gene clusters and understanding in great detail the biosynthetic pathways leading towards commercially important phosphonates such as phosphinothricin and fosfomycin. As the genetic and biochemical studies became more efficient, a new bottleneck was idenyified that involves inefficient purification strategies and hence slow-down of structure elucidation of the products of newly discovered gene clusters. Part of the proposed studies in this subproject will focus on the development of efficient methods for purification and structural elucidation of those new compounds. In addition, the genome sequencing efforts of the past grant period identified cases in which the same natural product is made in different organisms by very different biosynthetic routes. We will investigate these examples of convergent evolution. Finally, many natural product phosphonates are produced as short peptides to promote uptake by peptide permeases in the target organisms. Whereas for some compounds small non-ribosomal pepfide synthetase (NRPS) clusters are responsible for peptide bond formation, many phosphonate containing peptides are assembled In different, often unidentified ways. We will attempt to provide more insight into this very important aspect with respect to possible future engineering efforts.