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

我们研究了由多种金属取代的血红素和铁-氯衍生物重组而成的血球蛋白衍生物的结构和功能。制备了钼(Mo)和钨(W)取代肌红蛋白(Mb)和辣根过氧化物酶(HRP)(其中用Mo=0或w=0取代血红素铁)。结果表明，Mb有利于还原状态(4)，而HRP稳定在氧化状态(5)。用Irate氧化镍(II)取代的Mb、Hb和Hrp，以检测这些血红蛋白中是否形成了卟啉阳离子自由基。结果发现，在所有的血球蛋白中都形成了Ni(II)-卟啉-lt；pi&gt；-阳离子自由基，尽管它在Mb和Hb中不如在Hrp中稳定。讨论了这些结果与天然Mb和Hrp的高氧化态的不同特征。通过血红素取代&lt；α&gt；或&lt；β&gt；亚基中的Ru(II)钴-次卟啉，合成了双取代Ru-Fe杂化HBS。亚基间氢键质子的核磁共振谱表明，在低pH值下，两个互补杂化分子的四级结构均保持“类T”状态，表明T-R结构的转换是由第三个配体分子的连接引起的。我们还研究了含铁-氯基的血球蛋白及其模型氯络合物。

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.