STRUCTURAL BIOLOGY OF PROSTAGLANDIN BIOSYNTHESIS

前列腺素H合成酶(PGHS)是一种完整的膜蛋白。 将必需脂肪酸花生四烯酸转化为首字母 通过自由基机制，酶解产物PGG2和PGH2。 前列腺素引发多种细胞和组织反应，包括 血管扩张，血管收缩，血液凝结，细胞增殖和 发炎。非类固醇抗炎药(NSAIDs)，它抑制 通过靶向PGHS的环氧合酶活性来合成前列腺素， 用于治疗炎症和心血管疾病的某些症状 疾病。前列腺素还参与了许多疾病的病理生理过程。 包括动脉粥样硬化、类风湿性关节炎和癌症在内的疾病 后者，阿司匹林现在被证明是一种抗癌预防药物。两种异构体 已发现：PGHS-1参与动态平衡或“房屋- 在细胞因子诱导PGHS-2的同时保持前列腺素的生物合成 在炎症性事件中。 我们正在继续努力，以确定其X射线晶体结构 将PGHS-1调到尽可能高的分辨率。我们已经解决了 PGHS-1至3.1A分辨率，建立了该酶的原子模型，并 表征了PGHS-1与四种非甾体抗炎药的络合物a=：溴阿司匹林， 氟比洛芬、碘-舒洛芬和碘-吲哚美辛。我们开始 在同步辐射下收集高分辨率数据(2.8A) 需要进一步技术发展的设施，如 膜蛋白晶体的快速冷冻。我们将继续研究 酶-药物相互作用的本质和结构-功能 关系，特别侧重于底物和 NSAID的相互作用以及靶向内质网的方式。这 将涉及分析配体诱导的PGHS-1的构象变化， 用X-射线衍射仪表征了PGHS-1和PGHS-2的配体配合物 补充系列的酶学、EPR/Endor光谱和X射线 衍射实验。随着PGHS一种可诱导形式的发现， 人们对PGHS-1和PGHS-2之间的功能差异提出了质疑。 我们利用已知的序列和序列预测了PGHS-2的结构 以PGHS-1为模型，正在进行结构功能分析 在这种新的同工酶中的关系。小鼠PGHS-2的结晶实验 正在进行中。

Prostaglandin H synthase (PGHS) is a an integral membrane protein which converts arachidonic acid, an essential fatty acid, into the initial enzymatic products, PGG2 and PGH2 by means of a free radical mechanism. Prostaglandins initiate numerous cell and tissue responses including vasodilation, vaso-constriction, blood clotting, cell proliferation and inflammation. Nonsteroidal anti-inflammatory drugs (NSAIDs), which inhibit prostanoid biosynthesis by targeting the cyclooxygenase activity of PGHS, are used to treat certain symptoms of inflammatory and cardiovascular diseases. The prostanoids are also involved in pathophysiology of a number of diseases including atherosclerosis, rheumatoid arthritis, and cancer; in the latter, aspirin is now a proven anticancer prophylaxis. Two isoforms of PGHS have been discovered: PGHS-1 is involved in homeostatic or "house- keeping" prostaglandin biosynthesis while PGHS-2 induced by cytokines during inflammatory events. We are continuing our efforts to determine the X-ray crystal structure of PGHS-1 to the highest resolution possible. We have solved the structure of PGHS-1 to 3.1 A resolution, have built an atomic model of the enzyme, and have characterized PGHS-1 complexes a=with four NSAIDs: bromoaspirin, flurbiprofen, iodosuprofen and iodoindomethacin. We are beginning to collect high resolution data (2.8 A) at the synchrotron radiation facilities which will require further technological development such as the flash-freezing of membrane protein crystals. We will continue our study on the nature of enzyme-drug interactions and structure-function relationships, with particular focus on the mechanisms of substrate and NSAID interactions as well as the mode of targeting the ER membrane. This would involve analyzing ligand-induced conformational changes in PGHS-1, and characterizing ligand complexes of PGHS-1 and PGHS-2 by means of a complementary series of enzymological, EPR/ENDOR spectroscopic and X-ray diffraction experiments. With the discovery of an inducible from of PGHS, questions arise about the functional differences between PGHS-1 and PGHS-2. We have predicted the structure of PGHS-2, using the known sequences and the PGHS-1 as a model, and are analyzing the structure-function relationships in this new isozyme. Crystallization trial for mouse PGHS-2 are underway.