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

我们研究了各种金属取代血红素和铁-氯衍生物重组的血红蛋白衍生物的结构和功能。制备了钼（Mo）和钨(W)代替肌红蛋白（Mb）和辣根过氧化物酶（HRP）（其中血红素铁由Mo=0或W =0代替）。发现Mb倾向于还原态（+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，检测这些血红蛋白中是否形成卟啉<pi>-阳离子自由基。结果发现，在所有这些血红蛋白中都形成了Ni(II)-卟啉<pi>-阳离子自由基，尽管其在Mb和Hb中的稳定性低于HRP。这些结果与天然Mb和HRP的高氧化态的不同特征有关。在< α >或< β >亚基上，原血红素被Ru(II)CO-deuteroporphyrin取代，合成了二钌取代的Ru- fe杂化Hbs。亚基间氢键质子的质子核磁共振谱显示，在低pH下，两个互补杂化体的四元结构都保持在“T-态”，表明T到R的结构转化是由第三配体分子的连接引起的。E也研究了含铁-氯基的血红蛋白及其模型氯配合物。

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.