MECHANISM AND KINETICS OF SICKLE CELL HEMOGLOBIN

镰状细胞病的特征是突变体的聚合 在缺氧条件下血红蛋白的形式，增加红血 细胞僵硬导致微血管闭塞。 的严重程度 疾病很可能部分取决于 聚合过程中的缺氧条件和动力学 在肺处复氧后解聚（熔化）。 虽然 聚合机理和动力学已经被广泛地 尽管已经进行了大量的研究，但集中在聚合物熔融方面的工作要少得多。 重点 本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。 将特别注意 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。 的其他因素 可以影响熔融动力学，例如聚合物的长度将 研究以及聚合物熔融动力学和变化之间的联系 镰状细胞的形状和变形能力。 这项研究不仅 对于理解聚合的物理学和 解聚作用，同时也有助于理解镰状细胞病 从而为新的治疗形式提供了可能性。 拟议的工作将通过一种新颖的组合来完成， 光谱技术 一种特殊的仪器， 同时进行吸收光谱测量，线性 二色性、圆二色性、圆偏振发光，以及 偏振光散射正在建立应用于这一点， 项目 光谱测量将通过 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， 血红蛋白分子的四级状态可以同时 确定为引发聚合物熔融。 使用这些 本项目中的光谱技术（及其组合）可以 从而在其他研究中应用。 将特别注意 在评估偏振光散射（先前示出为 对聚合物浓度极其敏感）作为生物物理学工具。 这项新技术提供了执行这一任务的能力， 独特的测量组合确保了 发现新现象。

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.