Synthesis, Structure, and Activity of Supramolecular Mimics for the Active Site and Arg141 Residue of Copper, Zinc-Superoxide Dismutase
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- 作者：Ying-Hua Zhou ; Heng Fu ; Wei-Xi Zhao ; Wei-Lin Chen ; Cheng-Yong Su ; Hongzhe Sun ; Liang-Nian Ji ; Zong-Wan Mao
- 刊名：Inorganic Chemistry
- 出版年：2007
- 出版时间：February 5, 2007
- 年：2007
- 卷：46
- 期：3
- 页码：734 - 739
- 全文大小：186K
- 年卷期：v.46,no.3(February 5, 2007)
- ISSN：1520-510X
文摘
Two supramolecular complexes, [Cu(L)(H2O)2(
-CD)](ClO4)2·10.5H2O·CH3OH (1) and [Cu(L)(H2O)2(-GCD)](HClO4)(ClO4)2·10H2O (2) (L = 4-(4'-tert-butyl-benzyl)diethylenetriamine, -CD = -cyclodextrin, and -GCD = mono-6-deoxy-6-guanidinocycloheptaamylose cation), have been synthesized. The structure of 1 has been characterizedby X-ray crystallography. The 4-tert-butyl-benzyl of [Cu(L)(H2O)2]2+ moiety in 1 as a guest inserts into the hydrophobiccavity of the -CD as a host along the primary hydroxyl side. On the basis of the structure data of 1, complex 2was modeled, which showed that the distance between the Cu and C atom of the guanidinium is 5.2 Å, comparableto the corresponding distance in bovine erythrocyte Cu, Zn-SOD (5.9 Å) (SOD = superoxide dismutase). Apparentinclusion stability constants of the host and the guest were measured to be 0.66 (±0.01) × 104 and 1.15 (±0.03)× 104 M-1 for 1 and 2 respectively. The electronic absorption bands and electronic reflection bands of each complexare almost the same, indicating an identical structure of the complex in aqueous solution and in solid state. Thetwo complexes showed quasi-reversible one-electron Cu(II)/Cu(I) redox waves with redox potentials of -0.345 and-0.338 V for 1 and 2, respectively. Their SOD-like activities (IC50) were measured to be 0.30 ± 0.01 and 0.17 ±0.01 
M by xanthine/xanthine oxidase-NBT assay. The enhanced SOD activity of 2 by ~40% compared with 1suggests that the guanidyl cation in the host of the supramolecular system of 2 can effectively mimic the side chainof Arg141 in the enzyme, which is known to be essential for high SOD activity possibly through steering of thesuperoxide substrate to and from the active copper ion.
-CD)](ClO4)2·10.5H2O·CH3OH (1) and [Cu(L)(H2O)2(-GCD)](HClO4)(ClO4)2·10H2O (2) (L = 4-(4'-tert-butyl-benzyl)diethylenetriamine, -CD = -cyclodextrin, and -GCD = mono-6-deoxy-6-guanidinocycloheptaamylose cation), have been synthesized. The structure of 1 has been characterizedby X-ray crystallography. The 4-tert-butyl-benzyl of [Cu(L)(H2O)2]2+ moiety in 1 as a guest inserts into the hydrophobiccavity of the -CD as a host along the primary hydroxyl side. On the basis of the structure data of 1, complex 2was modeled, which showed that the distance between the Cu and C atom of the guanidinium is 5.2 Å, comparableto the corresponding distance in bovine erythrocyte Cu, Zn-SOD (5.9 Å) (SOD = superoxide dismutase). Apparentinclusion stability constants of the host and the guest were measured to be 0.66 (±0.01) × 104 and 1.15 (±0.03)× 104 M-1 for 1 and 2 respectively. The electronic absorption bands and electronic reflection bands of each complexare almost the same, indicating an identical structure of the complex in aqueous solution and in solid state. Thetwo complexes showed quasi-reversible one-electron Cu(II)/Cu(I) redox waves with redox potentials of -0.345 and-0.338 V for 1 and 2, respectively. Their SOD-like activities (IC50) were measured to be 0.30 ± 0.01 and 0.17 ±0.01 M by xanthine/xanthine oxidase-NBT assay. The enhanced SOD activity of 2 by ~40% compared with 1suggests that the guanidyl cation in the host of the supramolecular system of 2 can effectively mimic the side chainof Arg141 in the enzyme, which is known to be essential for high SOD activity possibly through steering of thesuperoxide substrate to and from the active copper ion.