STRUCTURAL AND DYNAMIC STUDY OF MODEL HEME COMPLEXES

将使用各种核磁共振方法来 研究一系列精选的血红素蛋白，目的是 了解控制血红蛋白功能的机制。这 计划将强调，但不限于，探索和 顺磁超精细位移信息量的研究进展 详细的分子/电子学方面的血红素蛋白的形式 在血红素腔中的结构。最终目标是能够确定 根据核磁共振数据，单点突变的结构后果 导致Hb A功能受损。我们计划的基石是 继续独特地利用选择性同位素标记的血红素来定位 并指定了1H，2H和13C血红素的共振和间接发展 确定潜在功能分配的核磁共振方法 血红素腔内的相关氨基酸侧链。这些系统将是 研究是在现有数据的基础上选择的，以便于 用核磁共振波谱参数的差异解释核磁共振波谱参数 可以与功能差异相关联的结构。中心到 我们的研究是一系列肌红蛋白和变构单体(摇蚊) 和二聚体(摇蚊、不等效摇蚊)血红蛋白，作为 Hb A的简化模型指定的峰将用于 从详细的角度定量地描述超精细漂移的起源 低自旋铁蛋白的结构，以建立经验关联 在脱氧肌红蛋白和血红蛋白中具有血红素空腔的结构，以及 开发多种用于结构功能的通用核磁共振探针 在血色素蛋白中的关系。的信息内容和范围 核磁共振检测完整肌肉中肌红蛋白的适用性将是 探索过了。平衡的血红素取向紊乱现象和 影响蛋白质-血红素外周接触的因素将被阐明。 在天然和重组的血红素蛋白中，重点是 血红素取向对二聚体和亚基内相互作用的影响 四聚体血红蛋白。个体障碍的氧亲和力 组件将被确定。载脂蛋白的反应机理 与亚铁血红素和亚铁血红素定向无序中间体在 血红蛋白的重组和生物合成将在一个 肌红蛋白和血红蛋白的种类。为以下目的开发的结构探头 模型肌红蛋白将被用于阐明分子。 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.