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Studies on the Molecular Engineering of Functional Regulations of Synthetic Pigment Substituted Hemoproteins

合成色素取代血红素蛋白功能调控的分子工程研究

基本信息

批准号：
61470079
负责人：
MORISHIMA Isao
金额：
$ 4.1万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1987
项目状态：
已结题

项目摘要

We have studied the structures and functions of hemoprotein derivatives reconstituted with a variety of metal-substituted hemes and iron-chlorin derivatives. Molybdenum (Mo) and tungustem (W) substituted myoglobin (Mb) and horseradish peroxidase (HRP) (where the heme iron is replaced by Mo=0 or w=0) were prepared. It was found that Mb favors the reduced state (+4), while HRP stabilizes in the oxidized state (+5). Nickel(II)-substituted Mb, Hb and HRP were oxidized with iridate to examine whether porphyrin <pi>-cation radical is formed or not in these hemoproteins. It was found that Ni(II)-porphyrin <pi>-cation radical is formed in all of these hemoproteins, although it is less stable in Mb and Hb than in HRP. Tese results are discussed in relation to the different features of higher oxidation states of native Mb and HRP. Diruthenium-substituted Ru-Fe hybrid Hbs were synthesized by heme substitution from protoheme to Ru(II)CO-deuteroporphyrin in the <alpha> or <beta> subunits. The proton NMR spectra of the intersubunit hydrogen-bonded protons showed that the quaternary structures of the two complementary hybrids both remain in the "T-like-state" at low pH, suggesting that the T to R structural conversion is induced by ligation of the third ligand molecule. E have also studied hemoproteins containing iron-chlorin prosthetic groups and their model chlorin complexes.

我们研究了血红素蛋白衍生物的结构和功能与各种金属取代的血红素和铁二氢卟酚衍生物。制备了钼（Mo）和钨（W）取代的肌红蛋白（Mb）和辣根过氧化物酶（HRP）（其中血红素铁被Mo=0或W=0取代）。结果发现，Mb有利于还原态（+4），而HRP稳定在氧化态（+5）。用铱酸盐氧化镍（Ⅱ）取代的Mb、Hb和HRP，以检测<pi>这些血红素蛋白中是否形成卟啉阳离子自由基。结果表明，在所有这些血红素蛋白中均形成了Ni（Ⅱ）-卟啉<pi>-阳离子自由基，尽管它在Mb和Hb中的稳定性不如在HRP中。Tese结果进行了讨论有关的不同功能的本地Mb和HRP的较高的氧化态。通过亚铁血红素取代Ru（II）CO-次卟啉，合成了二钌取代的Ru-Fe杂化血红蛋白<alpha><beta>。亚基间氢键质子的质子NMR谱表明，在低pH下，两个互补杂合体的四级结构都保持在“类T-状态”，这表明T到R结构的转换是由第三配体分子的连接引起的。E还研究了含铁二氢卟酚辅基的血红素蛋白及其模型二氢卟酚复合物。