ELECTRON MICROSCOPY OF HUMAN ALPHA-2-MACROGLOBULIN

人 ALPHA-2-巨球蛋白的电子显微镜

• 批准号: 3361239
• 负责人: JAMES K STOOPS
• 金额: $ 11.62万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-09-01 至 1993-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3361239
• 关键词: chemical binding; cryoscience; glycoprotein structure; human tissue; image enhancement; immunoelectron microscopy; immunoglobulins; macroglobulins; protease inhibitor; protein structure function; receptor binding; stainings; thioester; trypsin

alpha2-Macroglobulin (alpha2M) is a major inhibitor of virtually all known endoproteases found in the plasma of vertebrates. It has been suggested that it serves as a general protease scavenger, thereby protecting the blood and tissue proteins from degradation. As a protease inhibitor, it may play a role in the regulation of protease activity in fibrinolysis, coagulation, and complement activation. As a result, alpha2M is a large glycoprotein (Mr=725,000) composed of four identical subunits. Protease inhibition is accompanied by a major change in its structure resulting in entrapment of the protease. In order to determine the mechanism by which the native structure rearranges to the protease-bound form, immunoelectron microscopy will be employed. The structures will be visualized using both negative-stain and cryoelectron microscopy and maximum resolution of these micrographs will be achieved by image processing. Immunoelectron microscopy and gold cluster labeling will also be utilized to locate the sites of biological interest, which include the "bait" region, the receptor-binding sites, and the thioesters. Further details of the structural consequences of protease binding will be studied by electron microscopy of the methylamine-treated and the alpha2M-protease complexes with one and two molecules of trypsin bound.

alpha2-macroglobolin（alpha2m）是几乎所有已知的主要抑制剂 在脊椎动物的血浆中发现的内螺旋虫。 有人建议 它是一般的蛋白酶清除剂，从而保护 血液和组织蛋白降解。 作为蛋白酶抑制剂，它 可能在纤维蛋白溶解中蛋白酶活性的调节中起作用， 凝结和补体激活。 结果，α2M是一个大的 糖蛋白（MR = 725,000）由四个相同的亚基组成。 蛋白酶 抑制作用伴随着其结构的重大变化，导致 蛋白酶的夹带。 为了确定该机制 天然结构重新安排蛋白酶结合形式，即免疫电子 将使用显微镜。 结构将使用两者都可以看到 负染色和冷冻电子显微镜以及这些的最大分辨率 显微照片将通过图像处理来实现。 免疫电子 显微镜和金簇标记也将用于定位 生物兴趣的网站，其中包括“诱饵”地区， 受体结合部位和硫代植物。 进一步的细节 蛋白酶结合的结构后果将由电子研究 甲胺处理的显微镜和α2M-蛋白酶复合物 具有胰蛋白酶结合的一个和两个分子。