FUNGAL CELL WALL ENZYMOLOGY--(1-3)-B-GLUCAN SYNTHASE

真菌在医学上和经济上都非常重要，造成浪费， 腐败和疾病。 治疗人类真菌疾病，尤其是 免疫缺陷患者，例如患有获得性免疫缺陷的患者， 免疫缺陷综合征，是阻碍了非常少的临床有用的药物。 丝状真菌的形态发生和生长是 多糖聚合物和其它材料依次沉积在 每个菌丝顶端导致成熟细胞壁的形成。 细胞壁 组装产生含有几丁质、β（1-3）葡聚糖和其它多糖的壁。 β-和α-连接的葡聚糖、蛋白质和脂质。 也许是关键的一步 真菌细胞壁组装的关键步骤是β（1-3）的合成， 葡聚糖及其随后掺入细胞壁。 这项建议 其目的是详细了解（1-3）-β-D-葡聚糖 合成酶，负责葡聚糖合成的酶。 1.（1-3）-β-葡聚糖体外测定条件的建立 许多人类病原真菌，例如，组织胞 capsulatum、新型隐球菌、构巢曲霉、A.烟曲霉， 须癣毛癣菌、施内克孢子丝菌和芽生菌 皮肤炎 2.详细比较了来自不同来源的（1-3）-β-葡聚糖合酶活性， 上述病原真菌以及粗糙脉孢菌和白色念珠菌。 这将包括各种动力学参数的测定 （底物、离子、最适pH值、各种抑制剂和活化剂）和 详细的产品特征。 GTP结合调节蛋白 将被净化和鉴定。 3.分离、分子克隆和鉴定编码 来自粗糙脉孢菌（Neurospora crassa）的（1-3）-β-葡聚糖合酶活性。

Fungi are medically and economically very important, contributing to waste, spoilage and disease. Treatment of human fungal disease, especially in immunodeficient patients, for example those suffering from Acquired Immunodeficiency Syndrome, is hampered by very few clinically useful drugs. Filamentous fungal morphogenesis and growth are the direct result of polysaccharide polymers and other materials being sequentially deposited at each hyphal apex leading to the formation of a mature cell wall. Cell-wall assembly results in a wall containing chitin, beta(1-3) glucan, and other beta- and alpha- linked glucans, proteins and lipids. A key step, perhaps the key step, in fungal cell wall assembly is the synthesis of beta(1-3) glucan and its subsequent incorporation into the cell wall. This proposal has as its aim, the detailed understanding of (1-3) - beta-D-glucan synthase, the enzyme responsible for glucan synthesis. 1.The development of in vitro conditions for the assay of (1-3)-beta-glucan synthase activity of a number of human pathogenic fungi, e.g., Histoplasma capsulatum, Cryptococcus neoformans, Aspergillus nidulans, A. fumigatus, Trichophyton mentagrophytes, Sporothrix schneckii, and Blastomyces dermatitidis. 2.Detailed comparison of (1-3)-beta-glucan synthase activities from the above pathogenic fungi and those of Neurospora crassa and Candida albicans. This will include the determination of various kinetic parameters (substrate, ions, pH optimum, various inhibitors and activators) and detailed product characterization. The GTP-binding regulatory protein will be purified and characterized. 3.Isolation, molecular cloning, and characterization of the gene(s) coding from (1-3)-beta-glucan synthase activity of Neurospora crassa.