INHIBITION AND MECHANISM STUDIES OF SECRETED PHOSPHOLIPASE A2, KYNURENINE AMI

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 新型分泌型磷脂酶A2（sPLA 2）抑制剂 sPLA 2酶调节精氨酸介导的炎症途径。外源性Ⅱ A族sPLA 2（sPLA 2-IIA）可增强类风湿关节炎患者滑膜成纤维细胞样细胞产生前列腺素E2（PGE 2）。此外，sPLA 2-IIA可诱导前列腺癌细胞增殖。sPLA 2-IIA表现出酶促和活性独立的作用，我们已经开发出阻断两者的抑制剂。我们现在常规地实现抑制剂酶复合物的1.6分辨率的数据集。我们正在开发更有效的抑制剂，并寻求证实其预测的机制。 人犬尿氨酸氨基转移酶-I（hKAT-I） hKAT-I催化由犬尿氨酸形成犬尿烯酸。犬尿烯酸在精神分裂症患者的大脑和CSF中的水平升高。这是显著更高的脑hKAT-I活性的结果，并且是这样的抑制剂将是有效的抗精神病剂的令人信服的证据，然而目前没有已知的hKAT-I的特异性抑制剂。初步结果表明，这些化合物表现出较强的结合和有效的抑制hKAT-I。hKAT-I抑制剂复合物的结构将阐明抑制机制，并有助于设计更有效的类似物。 谷氨酰胺转移酶2（TG 2）的催化作用和别构调节 TG 2是一种普遍存在的多功能蛋白。其交联（TG）活性在纤维化疾病、腹腔疾病和神经病中是重要的;其GTdR活性通过其作为受体偶联G蛋白的功能介导细胞信号传导。TG活性的催化细节在底物进入埋藏的活性位点方面以及通过钙（激活TG活性）和GTP（抑制TG活性）对TG 2的变构调节机制仍然知之甚少。我们建议确定TG-非活性（GTP-结合）和TG-活化（钙结合或无底物）TG 2的结构。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. NEW INHIBITORS OF SECRETED PHOSPHOLIPASE A2 (sPLA2) sPLA2 enzymes regulate cytokine-mediated inflammatory pathways. Exogenous Group IIA sPLA2(sPLA2-IIA)can enhance prostaglandin E2(PGE2)production in fibroblast-like synovial cells from RA patients. Furthermore sPLA2-IIA can induce the proliferation of prostate cancer cells. sPLA2-IIA exhibits both enzymatic and activity independent actions and we have developed inhibitors that block both. We now routinely achieve datasets to 1.6 Ǻ resolution the inhibitor enzyme complexes. We are developing more potent inhibitors and seek to confirm their predicted mechanism. HUMAN KYNURENINE AMINOTRANSFERASE-I (hKAT-I) hKAT-I catalyses the formation of kynurenic acid from kynurenine. Kynurenic acid is found in elevated levels in the brains and CSF of patients with schizophrenia. This is a consequence of significantly higher brain hKAT-I activity and is compelling evidence that such an inhibitor would be an efficacious anti-psychotic agent, however there are currently no known specific inhibitors of hKAT-I. The preliminary results suggest that these compounds exhibit strong binding and potent inhibition of hKAT-I. The structure of the hKAT-I inhibitor complexes will elucidate the mechanism of inhibition and aid in the design more potent analogues. CATALYSIS AND ALLOSTERIC REGULATION OF TRANSGLUTAMINASE 2 (TG2) TG2 is a ubiquitous multi-functional protein. Its cross-linking (TG) activity is important in fibrotic disorders, coeliac disease and neuropathies; its GTPase activity mediates cell signalling through its function as a receptor-coupled G-protein. Catalytic details of TG activity in terms of substrate access to the buried active site well as the mechanism of allosteric regulation of TG2 by calcium (to activate TG activity) and GTP (to inhibit TG activity) remain poorly understood. We propose to determine the structures of TG-inactive (GTP-bound) and TG-activated (calcium-bound with or without substrate) TG2.