XRAY ROTATION CAMERA STUDIES OF SULFITE OXIDASE

亚硫酸氧化酶的 X 射线旋转摄像机研究

• 批准号: 6119426
• 负责人: JOHN H ENEMARK
• 金额: --
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-03-01 至 2000-04-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6119426
• 关键词: biomaterials; enzymes; proteins

The molybdenum-containing enzyme sulfite oxidase catalyzes the conversion of sulfite to sulfate, the terminal step in the oxidative degradation of cysteine and methionine. Deficiency of this enzyme in humans usually leads to major neurological abnormalities and early death. Chicken liver sulfite oxidase has 68% sequence identity with the human enzyme, and the structure of the chicken liver enzyme has been solved from data collected at SSRL to 1.9 E resolution. The structure reveals that the protein is dimeric, and the Mo atom pentacoordinated by three sulfur ligands, an oxo group and one water/hydroxo ligand. A sulfate molecule adjacent to the Mo identifies the substrate binding pocket. The structure enables four variants associated with sulfite oxidase deficiency in humans to be related to structure. Two are near the sulfate binding site; two occur within the domain mediating dimerization. The distance between the Mo and Fe of the heme of 32 E is surprisingly long considering the rates of intramolecular electron transfer in the protein.

含钼酶亚硫酸盐氧化酶催化 亚硫酸盐转化为硫酸盐，氧化反应的最后一步 半胱氨酸和蛋氨酸的降解。 缺乏这种酶 人类通常会导致严重的神经系统异常和早期 死亡。 鸡肝亚硫酸氧化酶与 68% 的序列同一性 人类酶，鸡肝酶的结构有 已从 SSRL 收集的数据中以 1.9 E 分辨率解决。 这 结构表明该蛋白质是二聚体，Mo原子 由三个硫配体、一个氧代基团和一个五配位 水/羟基配体。 与 Mo 相邻的硫酸盐分子 识别底物结合袋。 该结构使四个 与人类亚硫酸氧化酶缺乏相关的变异 与结构有关。 两个靠近硫酸盐结合位点；二 发生在介导二聚化的域内。 之间的距离 考虑到 32 E 的血红素的 Mo 和 Fe 令人惊讶地长 蛋白质中分子内电子转移的速率。