Biosynthesis of Hypotensive Phosphonopeptide Natural Products

描述(申请人提供)：来自放线菌的天然产物‘K-26’代表了一类未被研究的天然碳-磷键化合物，其中包含一种含有酪氨酸的磷酸类似物。K-26具有血管紧张素转换酶(ACE)抑制活性，其IC50值为12.5 NM，与广泛使用的降压药卡托普利相当。K-26由N-乙酰异亮氨酸、酪氨酸和非蛋白生成氨基酸(R)-1-amino-2-(4-hydroxyphenyl)ethylphosphonic酸(AHEP)组成。尽管K-26及其相关化合物具有很强的降压活性，但K-26，更具体地说，AHEP的生物合成途径仍未确定。AHEP的芳香族氨基酸功能表明其起源于莽草酸途径。然而，很难合理地解释磷酸烯醇式丙酮酸变位酶如何整合到经典的氨基酸代谢中来产生AHEP。我们描述了初步数据，证明AHEP来自酪氨酸，并且C-P键形成化学是独特的。我们假设了C-P键的形成机制，并提出了一系列的研究，以(1)确定K-26的基本组成单元和组装途径，(2)确定与K-26生物合成有关的基因，(3)表征K-26的生物合成机制，特别是C-P键的形成生物化学。对公众健康的影响：拟议的研究将是对一类独特的含有芳香膦酸的化合物的生物合成的首次研究，这类化合物已被证明具有强大的金属蛋白酶抑制活性。因此，这一提议将为发现和重组生物催化生成具有治疗作用的新型磷酸功能金属蛋白酶抑制剂提供重要的新工具。金属蛋白酶抑制剂具有治疗大量人类疾病的潜力，包括高血压、癌症和骨关节炎等。

DESCRIPTION (provided by applicant): The natural product 'K-26' from an actinomycete is representative of an uninvestigated class of natural carbon-phosphorus bond containing compounds which incorporate a phosphonic acid analog of tyrosine. K- 26 possesses angiotensin converting enzyme (ACE) inhibitory activity with an IC50 value of 12.5 nM, comparable to the widely prescribed antihypertensive drug Captopril. K-26 is comprised of N-acetylated isoleucine, tyrosine, and the nonproteinogenic amino acid, (R)-1-amino-2-(4-hydroxyphenyl)ethylphosphonic acid (AHEP). Despite the potent hypotensive activity of K-26 and related compounds, the biosynthetic pathways by which K-26 and more specifically AHEP are biosynthesized still remain uncharacterized. The aromatic amino acid functionality of AHEP suggests that its origin lies in the shikimic acid pathway. However, it is difficult to rationalize how phosphoenolpyruvate mutase, the activity responsible for forming all previously studied phosphonate containing natural products, can be integrated into classical amino acid metabolism to generate AHEP. We describe preliminary data that demonstrate that AHEP is derived from tyrosine and that the C-P bond forming chemistry is unique. We hypothesize a mechanism for C-P bond formation and propose a series of studies to (1) define the basic building blocks and pathway of assembly of K-26, (2) identify the genes responsible for K-26 biosynthesis and (3) characterize the K-26 biosynthetic machinery, especially the C-P bond forming biochemistry. Impact on public health: Proposed research will be the first study of the biosynthesis of a unique class of compounds containing an aromatic phosphonic acid, a class which has been demonstrated to have potent metalloproteinase inhibitory activity. As such, this proposal will provide significant new tools for the discovery and recombinant biocatalytic generation of therapeutically useful novel phosphonate functional metalloproteinase inhibitors. Metalloproteinase inhibitors have potential to treat a large number of human illnesses including hypertension, cancer and osteoarthritis, among others.