INHIBITION AND MECHANISM STUDIES OF SECRETED PHOSPHOLIPASE A2, KYNURENINE AMI

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 分泌型磷脂酶A2(SPLA2)的新抑制剂 SPLA2酶调节细胞因子介导的炎症途径。外源性IIA单链磷脂酶A2(sPLA2-IIA)可促进RA患者成纤维样滑膜细胞产生前列腺素E2(PGE2)。此外，sPLA2-IIA还能诱导前列腺癌细胞增殖。SPLA2-IIA表现出酶和活性非依赖的作用，我们已经开发出可以阻断这两种作用的抑制剂。我们现在常规地将数据集达到1.6&506；个抑制酶复合体的分辨率。我们正在开发更有效的抑制剂，并试图证实它们的预测机制。 人犬尿氨酸转氨酶-I(hKAT-I) HKAT-I催化犬尿氨酸生成犬尿酸。精神分裂症患者的大脑和脑脊液中犬尿酸水平升高。这是大脑hKAT-I活性显著增加的结果，也是令人信服的证据，表明这种抑制剂将是一种有效的抗精神病药物，但目前还没有已知的hKAT-I的特定抑制剂。初步结果表明，这些化合物对hKAT-I表现出很强的结合和强烈的抑制作用。HKAT-I抑制剂复合体的结构将阐明抑制作用的机制，并有助于设计更有效的类似物。 转谷氨酰胺酶2(TG2)的催化和变构调节 TG2是一种普遍存在的多功能蛋白质。它的交联(TG)活性在纤维化疾病、乳糜泻和神经疾病中很重要；它的GTPase活性通过其受体偶联G蛋白的功能来介导细胞信号传递。关于Tg活性的催化细节，如底物进入埋藏活性中心的途径，以及钙(激活Tg活性)和GTP(抑制Tg活性)对TG2的变构调节机制，目前尚不清楚。我们建议确定TG非活性(GTP结合)和TG激活(钙结合底物或不结合底物)TG2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.