STRUCTURAL AND DYNAMIC STUDY OF MODEL HEME COMPLEXES

将采用各种核磁共振方法， 研究一系列选定的血红素蛋白， 了解血红蛋白的功能控制机制。 这 计划将强调，但不限于，探索和 顺磁超精细位移信息量的发展 血红素蛋白的详细分子/电子形式 血红素腔中的结构。 最终目标是能够确定 从核磁共振数据的结构后果的单点突变， 导致Hb A功能受损。 我们计划的基石是 持续独特地利用选择性同位素标记的血红素来定位 并分配1H，2 H和13 C血红素共振和间接的发展， 用于确定性地分配潜在功能的NMR方法 血红素腔中的相关氨基酸侧链。 系统将 研究是根据现有数据选择的，以促进 解释NMR光谱参数的差异， 可以与功能差异相关的结构。 的核心 我们的研究是一系列的肌红蛋白和变构单体（摇蚊） 和二聚体（Chironomus，E.不相等的）血红蛋白， Hb A的简化模型。 分配的峰将用于 定量地描述超精细位移的起源， 低自旋铁蛋白的结构，以开发经验相关性 与脱氧肌红蛋白和血红蛋白中的血红素腔结构有关， 开发多种结构-功能通用核磁共振探针 血红素蛋白的关系。 信息内容和范围 在完整肌肉中肌红蛋白的NMR检测的适用性将是 探讨了 平衡血红素取向无序现象和 将阐明影响蛋白质-血红素外周接触的因素 在天然和重组血红素蛋白中，重点是 血红素取向对二聚体和 四聚血红蛋白 个体失调的氧亲和力 组件将被确定。 脱辅基蛋白的反应机理 与血红素和血红素取向无序中间体的作用， 血蛋白重建和生物合成的特征在于 各种肌红蛋白和血红蛋白。 结构探针开发用于 模型肌红蛋白将用于阐明 单体、二聚体和四聚体血红蛋白的变构机制。

A variety of nuclear magnetic resonance methods will be employed to investigate a series of selected heme proteins for the purpose of understanding the mechanisms of control of function for hemoglobins. This program will emphasize, but is not restricted to, the exploration and development of the information content of hyperfine shifts in paramagnetic forms of hemoproteins in terms of the detailed molecular/electronic structure in the heme cavity. The ultimate goal is to be able to determine from NMR data the structural consequences of single-point mutations which result in impaired function in Hb A. The cornerstone of our program is the continued unique utilization of selectively isotope-labeled hemes to locate and assign 1H, 2H and 13C heme resonances and the development of indirect NMR methodology for definitively assigning potentially functionally relevant amino acid side chains in the heme cavity. The systems to be studied are selected on the basis of data available to facilitate interpretation of NMR spectral parameters in terms of the difference in structure that can be correlated with difference in function. Central to our study are a series of myoglobins and allosteric monomeric (Chironomus) and dimeric (Chironomus, E. inequivalvis) hemoglobins which serve as simplified models for Hb A. The assigned peaks will be used to quantitatively describe the hyperfine shift origins in terms of detailed structure in low-spin ferric proteins, to develop empirical correlations with structure of the heme cavity in deoxy myoglobins and hemoglobins, and to develop a variety of general NMR probes for structure-function relationships in hemoproteins. The information content and scope of applicability of NMR detection of myoglobin in intact muscle will be explored. The phenomenon of equilibrium heme orientational disorder and the factors influencing protein-heme peripheral contacts will be elucidated in both native and reconstituted hemoproteins, with emphasis on the influence of heme orientation on intra-subunit interactions in dimeric and tetrameric hemoglobins. The oxygen affinity of individual disorder components will be determined. The mechanism of reaction of apo-proteins with hemes and the role of heme orientationally disordered intermediates in hemoprotein reconstitution and biosynthesis will be characterized in a variety of myoglobins and hemoglobins. The structural probes developed for the model myoglobins will be applied towards elucidating the molecular mechanism of allostery in monomeric, dimeric and tetrameric hemoglobins.