RUI: Structural and Dynamics Characterization of Dual Ligand Binding (H2S and 02) Processes in an Unusual Hemoglobin

本项目的目的是研究Lucina pectinata中分离的血红蛋白（Hb1）氧化还原和配体选择过程的分子基础。这种血红蛋白是由蛤和细菌之间的共生相互作用产生的，它将H2S运送到细菌中并结合O2。Lopez-Garriga博士将研究金属中心的还原/氧化如何影响卟啉环，以及配体与附近氨基酸的相互作用。关于这一点，Hb 1的配体结合特性可能受到由围绕血红素的苯丙酰残基阵列造成的低远端袋极性的影响。单体血红蛋白（如Hb 1）与极端疏水血红素口袋环境的研究可以为血红素蛋白提供有用的模型，以回答以下问题：配体选择是如何发生的？哪些配体-蛋白质的构象和结构变化是重要的？是什么控制着这些蛋白质中的配体反应性？血红素口袋芳香残基如何贡献或调节缔合和解离配体速率常数？为了回答这些问题，计划对Hb1和配体配合物（即H2S， O2和CO）进行共振拉曼，FTIR，时间分辨红外光谱和振动分析研究，以探索活性位点结构，氧化还原反应，Hb1构象和蛋白质功能之间的关系。% % %

9627773 Lopez-Garriga The goal of this project is to investigate the molecular basis for oxidation-reduction and ligand selection process of hemoglobin, (Hb1) isolated from Lucina pectinata. This hemoglobin, produced by a symbiotic interaction between the clam and a bacteria, transports H2S to the bacteria and binds O2. Dr. Lopez-Garriga will examine how reduction/oxidation of the metal center affects the porphyrin ring, and the ligand interaction with nearby amino acids. Regarding this, the ligand binding properties of Hb 1 may be influenced by the low distal pocket polarity resulting from the array of phenylalanyl residues surrounding the heme. Studies on monomeric hemoglobins, such as Hb 1, with extreme hydrophobic heme pocket environments can provide useful models for heme proteins to answer questions such as: How does ligand selection occur? Which ligand-protein conformational and structural changes are important? What controls ligand reactivity in these proteins? How do the heme pocket aromatic residues contribute or modulate the association and dissociation ligand rate constants? To answer these questions, Resonance Raman, FTIR, Time-Resolved Infrared Spectroscopy and Vibrational Analysis studies of Hb1 and ligand complexes (i.e. H2S, O2 and CO) are planned in order to probe the relation between the active site structure, oxidation-reduction reactions, Hb1 conformation, and the function of the protein. %%%