MECHANISM AND KINETICS OF SICKLE CELL HEMOGLOBIN

镰状细胞血红蛋白的机制和动力学

• 批准号: 2456404
• 负责人: DANIEL B KIM-SHAPIRO
• 金额: $ 8.46万
• 依托单位: WAKE FOREST UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-02-01 至 2003-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2456404
• 关键词: carbon monoxide; chemical binding; chemical kinetics; clinical research; erythrocytes; hemoglobin Ss; human subject; oxygen; polymers; protein denaturation; sickle cell anemia

Sickle cell disease is characterized by the polymerization of a mutant form of hemoglobin under hypoxic conditions which increases red blood cell rigidity leading to microvascular occlusion. The severity of the disease is most likely partially dependent on the kinetics of polymerization during hypoxic conditions and on the kinetics of depolymerization (melting) upon reoxygenation at the lungs. Although the mechanism and kinetics of polymerization have been extensively studied, much less work has concentrated on polymer melting. The focus of this study is to elucidate the mechanism and kinetics of sickle cell hemoglobin polymer melting. Special attention will be put on investigating the role of ligand (oxygen or carbon monoxide) binding to hemoglobin molecules in the polymer during melting. Other factors that may affect melting kinetics such as the length of the polymers will be studied as well as the link between polymer melting kinetics and changes in sickle cell shape and deformability. This study is not only important in regard to understanding the physics of polymerization and depolymerization but also in regard to understanding sickle cell disease thereby providing potential for a new form of treatment. The proposed work will be accomplished by a novel combination of spectroscopic techniques. A special instrument capable of simultaneously conducting spectral measurements of absorption, linear dichroism, circular dichroism, circularly polarized luminescence, and polarized light scattering is being built for application to this project. The spectral measurements will be accomplished with millisecond resolution so that the amount of sickle cell polymer, the ligation state of the polymer and solution phase molecules, and the quaternary state of the hemoglobin molecules can be simultaneously determined as polymer melting is induced. The use of these spectroscopic techniques (and their combination) in this project could lead to applications in other studies. Special attention will be paid in evaluating polarized light scattering (previously shown to be extremely sensitive to polymer concentration) as a biophysical tool. The novel technology that is providing the ability to perform this unique combination of measurements ensures the potential of the discovery of new phenomena.

镰状细胞病的特征是突变体的聚合 缺氧条件下血红蛋白的形式，增加红血 细胞刚性导致微血管闭塞。 严重程度 疾病很可能部分依赖于动力学 低氧条件下的聚合反应及其动力学 在肺部再氧合时解聚（熔化）。 虽然 聚合反应的机理和动力学已得到广泛研究 研究表明，很少有工作集中在聚合物熔融方面。 焦点 这项研究的目的是阐明镰状细胞的机制和动力学 血红蛋白聚合物熔化。 将会受到特别关注 研究配体（氧或一氧化碳）结合的作用 聚合物中的血红蛋白分子在熔化过程中。 其他因素 可能会影响熔融动力学，例如聚合物的长度 研究了聚合物熔融动力学和变化之间的联系 镰状细胞形状和变形能力。 这项研究不仅 对于理解聚合物理很重要 解聚还与了解镰状细胞病有关 从而为新的治疗方式提供了潜力。 拟议的工作将通过新颖的组合来完成 光谱技术。 一种特殊仪器能够 同时进行吸收光谱测量，线性 二色性、圆二色性、圆偏振发光和 偏振光散射正在为此应用而构建 项目。 光谱测量将通过以下方式完成 毫秒分辨率使得镰状细胞聚合物的量， 聚合物和溶液相分子的连接状态，以及 血红蛋白分子的四元态可以同时 当诱导聚合物熔化时确定。 这些的使用 该项目中的光谱技术（及其组合）可以 导致在其他研究中的应用。 将会受到特别关注 在评估偏振光散射时（之前显示为 对聚合物浓度极其敏感）作为生物物理工具。 提供执行此操作能力的新技术 独特的测量组合确保了潜力 新现象的发现。