Relationship of function and higher order structure of abnormal hemoglobin.

为了研究血红蛋白A （Hb A）的氧结合功能（变构）与四级结构变化之间的关系，利用紫外（UV）圆二色（CD）和紫外共振拉曼（UVRR）光谱对异常血红蛋白的结构和功能进行了研究。结果总结如下：(1)利用UVCD研究血红蛋白的四级结构变化：我们检测了α1-β2亚基界面氨基酸取代的异常血红蛋白的UVCD光谱（文献，1,2）。(1)利用紫外和可见共振拉曼研究表征了Hb M Iwate和Hb M Boston的血红素和蛋白质结构（文献，3,4）。(2)利用UVRR研究血红蛋白的结构和功能关系：235nm激发的Tyr和Trp RR波段在脱氧->氧（或CO）结构转变过程中发生了变化。我们使用异常血红蛋白、NO和金属杂化Hb澄清了Tyr或Trp残基导致了这些变化（参考文献，5-7）。从这些结果，我们已经阐明了α1-β2亚基界面上的Tyr和/或Trp残基对血红蛋白变构至关重要。这些芳香残基对血红蛋白的高阶蛋白质结构转变不是独立的，而是协同的。

In order to address the relationship between oxygen binding function (allostery) and quaternary structure changes of hemoglobin A (Hb A), we have studied on structure and function of abnormal hemoglobin by ultraviolet (UV) circular dichroism (CD) and UV resonance Raman (UVRR) spectroscopy. The results were summarized as follows :(1) A study of quaternary structure change of Hb by UVCD : We examined UVCD spectra of abnormal hemoglobin with amino acid substitution at α1-β2 subunit interface (References, 1, 2).(1) Heme and protein structure of Hb M Iwate and Hb M Boston characterized by UV and visible resonance Raman study (References, 3, 4).(2) Structural and functional relationship of hemoglobin by UVRR : Tyr and Trp RR bands excited with 235nm changed upon deoxy->oxy(or CO) structure transition. We clarified which Tyr or Trp residue contributed to these changes using abnormal hemoglobin, NO and metal-hybrid Hb (References, 5-7).From these results, we have elucidated that Tyr and/or Trp residues at α1-β2 subunit interface are critically important for hemoglobin allostery. These aromatic residues contribute not independently but cooperatively to higher order protein structure transition of hemoglobin.