Structural Determinants of Leghemoglobin Reactivity

本研究的长期目标是对调节配体与血红蛋白结合的结构和生物物理机制有更全面的了解。当前的目标是使用血红蛋白作为一个补充模型系统来测试血红蛋白功能的假设，这在很大程度上是基于对肌红蛋白的理解。这项工作涉及使用定点诱变、x射线晶体学和现代血红素振动模式分析方法，结合传统的动力学和光谱技术来分析大豆血红蛋白的结构和功能关系。已经证明这种蛋白利用与肌红蛋白不同的机制来调节配体结合。因此，对血红蛋白的全面研究无疑将为血红蛋白的结构和功能提供新的认识。血红素蛋白具有多种重要的生理功能。对单体血红素蛋白的基本了解为研究这些不同系统的结构和功能提供了一个起点，并允许合理设计将所需的特征纳入更好地理解血红蛋白。目前尚不清楚目前血红蛋白调节的假设机制可以在多大程度上转移到对其他血红蛋白的理解。通过该项目开展的研究将通过对单体血红蛋白——大豆血红蛋白的综合分析，检验目前关于血红蛋白功能的假设。对这种蛋白质的详细研究产生的对配体结合的更好理解将补充我们从传统模型系统中获得的对这些过程的理解。目标是为探索更复杂的多聚血红蛋白、氧传感器、过氧化物酶和相关酶的相同问题提供更多样化和完整的基础。

HargroveMCB 0077890The long-range goal of this research is to develop a more comprehensive understanding of the structural and biophysical mechanisms, which regulate ligand binding to hemoglobins. The immediate goals are to use leghemoglobin as a complementary model system to test hypotheses for hemoglobin function, which are based heavily on the understanding of myoglobin. This work involves the use of site-directed mutagenesis, X-ray crystallography, and modern methods for the analysis of heme vibrational modes in combination with traditional kinetic and spectroscopic techniques to analyze the relationship of structure and function in soybean leghemoglobin. It has been demonstrated that this protein exploits different mechanisms for regulating ligand binding than those used by myoglobin. Therefore, a comprehensive study of leghemoglobin will undoubtedly provide new insight into hemoglobin structure and function. Heme proteins carry out a variety of important physiological functions. A basic understanding of monomeric heme proteins provides a starting point for investigating the structure and function of these different systems and allows for rational design to incorporate desired characteristics into better understood hemoglobins. It is not clear to what degree the current hypothesized mechanisms for hemoglobin regulation can be transferred to an understanding of other heme proteins. The research carried out through this project will test the current hypotheses for hemoglobin function using a comprehensive analysis of a monomeric hemoglobin, soybean leghemoglobin. A better understanding of ligand binding generated from a detailed study of this protein will complement our understanding of these processes gained from traditional model systems. The goals are to provide a more diverse and complete basis for exploring the same questions about more complex, multimeric hemoglobins, oxygen sensors, peroxidases, and related enzymes.