STRUCTURAL ENERGETICS OF HEMOGLOBIN INTERMEDIATES

这项研究的目标是确定分子规则和驱动 调节蛋白质复合物生物功能的力。 人类 血红蛋白（Hb）正在研究以了解（i）中间体 亚基相互作用产生生理活性的状态和途径 协同性，以及（ii）中间体的机制如何 受生理效应物（H+、CO2、C1-）的调节。 这个程序 包括：（a）开发新的方法来分析能量 中间体四聚体对协同性的贡献;（B） 所产生的特定场地能量学与伴随的 结构变化; c使用单个氨基酸修饰探针 调节Hb能量成分的结构元件 协同性 我们早期的工作发现血红蛋白结构开关 遵循特定的组合规则：单个氨基酸的研究 对结合中间体的修饰已经揭示了重要的 血红蛋白四聚体结构能量学的对称/不对称特征 . 我们计划使用设计的重组血红蛋白来扩展这些研究。 O2中间体的改变的残基位点的组合。 亚基 重组系统的相互作用将通过技术进行研究 杂交，组装和动力学，以及直接O2 约束力 将通过X射线晶体学分析结构特征。 Hb调节系统是一个大家族的重要原型 合作的多位点调控组件。 因此， 该方案开发的软件应具有广泛的适用性。 更深 对人类Hb机制的理解也是当前研究人员的兴趣所在。 红细胞替代氧载体及药物的潜在设计 运载系统。

The goal of this research is to determine molecular rules and driving forces that regulate biological functions of protein complexes. Human hemoglobin (Hb) is being studied to understand (i) the intermediate states and pathways whereby subunit interactions generate physiological cooperativity, and (ii) how mechanisms of the intermediates are modulated by physiological effectors (H+, CO 2, C 1-). This program includes: (a) development of new methods to analyze energetic contributions to cooperativity by the intermediate tetamers; (b) correlation of the resulting site-specific energetics with accompanying structure changes; c usage of single amino acid modifications to probe structural elements which mediate the energetic components of Hb cooperativity. Our earlier work found that the Hb structural switches follow specific combinatorial rules: studies with single amino acid modifications to the binding intermediates have revealed important symmetry/asymmetry features of the Hb tetramer's structural energetics . We plan to extend these studies using recombinant Hb's with designed combinations of altered residue sites for the O2 intermediates. Subunit interactions of the recombinant systems will be studied by techniques of hybridization, assembly and kinetics, as well as by direct O2 binding. Structural features will be analyzed by X-ray crystallography. The Hb regulatory system is an important prototype for a large family of cooperative multi-site regulatory assemblies. Thus the methods developed by this program should have wide applicability. Deeper understanding of human Hb mechanisms is also of current interest to the potential design of red cell substitute oxygen carriers and drug delivery systems.