Faculty of Chemistry, University of Wrocław, Joliot-Curie 14, 50-383 Wroclaw, Poland.
Inorg Chem. 2013 May 20;52(10):5951-61. doi: 10.1021/ic400160d. Epub 2013 May 8.
Mononuclear and polynuclear copper(II) complexes of the alloferons 1 (Allo1) with point mutations (H6A) H(1)GVSGA(6)GQH(9)GVH(12)G-COOH (Allo6A) and (H12A) H(1)GVSGH(6)GQH(9)GVA(12)G-COOH (Allo12A) have been studied by potentiometric, UV-visible, CD, EPR spectroscopic, and mass spectrometry (MS) methods. Complete complex speciation at different metal-to-ligand ratios ranging from 1:1 to 3:1 was obtained. At physiological pH 7.4 and a 1:1 metal-to-ligand molar ratio, the Allo6A and Allo12A peptides form CuL complexes with the 4N {NH2, N(Im)-H(1),2N(Im)} binding mode. The amine nitrogen donor and the imidazole nitrogen atoms (H(9)H(12) or H(6)H(9)) can be considered to be independent metal-binding sites in the species formed for the systems studied. As a consequence, di- and trinuclear complexes for the metal-to-ligand 2:1 and 3:1 molar ratios dominate in solution, respectively. The induction of apoptosis in vivo in Tenebrio molitor cells by the ligands and their copper(II) complexes at pH 7.4 was studied. The biological results show that copper(II) ions in vivo did not cause any apparent apoptotic features. The most active was the Cu(II)-Allo12A complex formed at pH 7.4 with a {NH2, N(Im)-H(1),N(Im)-H(6),N(Im)-H(9)} binding site. It exhibited 123% higher of caspase activity in hemocytes than the native peptide, Allo1.
已通过电位法、紫外可见分光光度法、圆二色光谱法、电子顺磁共振波谱法和质谱法（MS）研究了具有点突变（H6A）H（1）GVSGA（6）GQH（9）GVH（12）G-COOH（Allo6A）和（H12A）H（1）GVSGH（6）GQH（9）GVA（12）G-COOH（Allo12A）的单核和多核铜（II）配合物。在从 1:1 到 3:1 的不同金属与配体比例下，获得了完整的配合物形态。在生理 pH 值 7.4 和 1:1 的金属与配体摩尔比下，Allo6A 和 Allo12A 肽以 4N {NH2、N（Im）-H（1）、2N（Im）} 结合模式形成 CuL 配合物。供体胺氮原子和咪唑氮原子（H（9）H（12）或 H（6）H（9））可被视为所研究体系中形成的物种中的独立金属结合位点。因此，在溶液中分别以金属与配体的 2:1 和 3:1 摩尔比为主导形成二核和三核配合物。在 pH 值为 7.4 时，研究了配体及其铜（II）配合物对黄粉虫细胞体内诱导凋亡的作用。生物学结果表明，体内铜（II）离子没有引起任何明显的凋亡特征。最活跃的是在 pH 值为 7.4 时形成的 Cu（II）-Allo12A 配合物，其具有 {NH2、N（Im）-H（1）、N（Im）-H（6）、N（Im）-H（9）} 结合位点。与天然肽 Allo1 相比，它在血细胞中的半胱天冬酶活性提高了 123%。
