Relationship of function and higher order structure of abnormal hemoglobin.

为了探讨血红蛋白A（Hb A）的氧结合功能（变构）与其四级结构变化的关系，采用紫外圆二色谱（CD）和紫外共振拉曼（UVRR）光谱技术对异常血红蛋白的结构和功能进行了研究。（1）UVCD研究血红蛋白四级结构的变化：我们研究了异常血红蛋白在α1-β2亚基界面发生氨基酸取代的UVCD光谱（参考文献1、2）。(1)通过紫外和可见共振拉曼研究表征Hb M Iwate和Hb M Boston的血红素和蛋白质结构（参考文献，3，4）。(2)利用UVRR研究血红蛋白的结构与功能关系：235 nm激发的Tyr和Trp RR带发生脱氧→氧（或CO）结构转变。我们利用异常血红蛋白、NO和金属杂合血红蛋白阐明了导致这些变化的Tyr或Trp残基（参考文献5-7）。这些芳香族残基不是独立地而是协同地促进血红蛋白的高级蛋白质结构转变。

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.