Mechanistic studies of PHB biosynthesis

描述（由申请人提供）：聚羟基链烷酸酯（PHA）是一类由许多细菌产生的微生物聚酯，作为细胞内碳和能量储存聚合物。它们显示从热塑性塑料到弹性体的材料特性。PHA的一个重要特性是它们在各种环境或生物系统中固有的生物降解性。因此，以环境友好和经济上有竞争力的方式用生物可降解塑料取代传统的基于石油化工的塑料的愿望已经成为该项目的推动力。这种新型的工程材料有望在心脏瓣膜和组织工程支架等方面得到广泛的应用。本提案的长期目标是确定和了解PHA生物合成及其调节所涉及的机制。具体地，为了区分提出的用于形成聚羟基丁酸酯（PHBs）的两种延伸机制，将采用涉及化学方法与突变酶的构建相结合的方法来捕获聚合中间体。晶体结构的研究将极大地加深对延伸机理的理解，并有助于更合理地设计基于机理的缓蚀剂。然而，迄今为止，尽管已经取得了一些进展，但还没有获得PHB酶的晶体。一系列化合物将被制备和探索作为共价酶抑制剂，以努力获得它们的晶体沿着与诱变方法。PHA是普遍感兴趣的，因为它们具有从热塑性塑料到弹性体的性质，并且是可生物降解的。了解PHA的生物合成是至关重要的工程新材料，目前正在审查其应用，如在心脏瓣膜和组织工程的支架。本项目的目的是鉴定和了解PHA生物合成及其调控机制。

DESCRIPTION (provided by applicant): Polyhydroxyalkanoates (PHAs) are a class of microbial polyesters produced by many bacteria as intracellular carbon and energy storage polymers. They display material properties ranging from thermoplastics to elastomers. An important characteristic of PHAs is their inherent biodegradability in various environments or biosystems. Thus, the desire to replace the conventional petrochemical-based plastics with biodegradable plastics in an environmentally friendly and economically competitive fashion has served an impetus for this project. The new engineered materials are expected find wide applications such as in heart valves and as scaffolds for tissue engineering. The long-term goal of this proposal is to identify and understand the machinery involved in PHA biosynthesis and its regulation. Specifically, in order to distinguish between the two elongation mechanisms proposed for the formation of polyhydroxybutyrates (PHBs), approaches involving chemical methods, in combination with the construction of mutant enzymes, to trap the polymerization intermediates will be employed. Crystal structures will greatly enhance the understanding of the elongation mechanism and help design mechanism-based inhibitors more rationally. However, to date, no crystals of PHB synthases have been obtained although some progress has been made. A series of compounds will be prepared and explored as covalent inhibitors of synthases in an effort to obtain their crystals along with mutagenetic methods. PHAs are of general interest as they possess properties that range from thermoplastics to elastomers and are biodegradable. Understanding the PHA biosynthesis is crucial to engineering new materials that are currently being examined for their applications such as in heart valves and as scaffolds for tissue engineering. The goal of this project is to identify and understand the machinary involved in PHA biosynthesis and its regulation.