NOVEL NMR STUDIES OF HEME PROTEINS INVOLVED IN ANEMIA

细胞色素b5是负责 维持血红蛋白在其功能减少的状态。 最近我们 已经找到证据表明脊椎骨的变化 细胞色素b5的动力学可能促进这种生理作用。 我们 测量了还原电位的温度依赖性， 使用范特霍夫式的数据分析，我们发现 与氧化有关的熵变是正的。 我们还 发现，基于氘交换动力学的测量， 氢键的强度会发生大规模的变化 在整个分子中氧化。 初步测量 还原态和氧化态的骨架动力学差异 蛋白质也符合这一假设。 通过更 详细分析场相关的15N弛豫数据，我们希望是 能够定量地将主链动力学的贡献与 与氧化有关的熵变 由Akke等人（1993）开发。

Cytochrome b5 is the terminal electron donor responsible for maintaining hemoglobin in its reduced functional state. Recently, we have found evidence that suggests that changes in the backbone dynamics of cytochrome b5 may facilitate this physiological role. We have measured the temperature dependence of the reduction potential and using a van't Hoff like analysis of the data, we find that the entropy change associated with oxidation is positive. We have also found, based on measurements of deuterium exchange kinetics, that large scale changes in the strengths of hydrogen bonds occur throughout the molecule upon oxidation. Preliminary measurements of differences in backbone dynamics in reduced and oxidized states of the protein are also consistent with this hypothesis. Through more detailed analyses of field dependent 15N relaxation data we hope to be able to quantitatively relate the contribution of backbone dynamics to the entropy change associated with oxidation using relationships developed by Akke, et al. (1993).