La Mendola Diego, Bonomo Raffaele P, Caminati Serena, Di Natale Giuseppe, Emmi Salvatore S, Hansson Orjan, Maccarrone Giuseppe, Pappalardo Giuseppe, Pietropaolo Adriana, Rizzarelli Enrico
Istituto di Biostrutture e Bioimmagini-CNR-Catania, Viale A. Doria 6, 95125 Catania, Italy.
J Inorg Biochem. 2009 Feb;103(2):195-204. doi: 10.1016/j.jinorgbio.2008.10.002. Epub 2008 Oct 14.
Potentiometric and spectroscopic (UV-Vis, CD and EPR) studies were carried out on copper(II) complexes with chicken prion protein N-terminal fragments, Ac-(PHNPGY)(4)-NH(2), and the mutated residue, Ac-(PHNPGF)(4)-NH(2), to assess the role of tyrosine in the copper coordination. Both thermodynamic and spectroscopic results indicate that chicken prion fragments are not able to bind more than two copper ions and only with the involvement of side chain tyrosine groups. The prevailing complex shows one copper ion bound to four imidazole nitrogen atoms in the 1:1 metal to ligand ratio systems. The superoxide dismutase (SOD)-like activity of copper(II) complexes with the avian peptides and mammal analogue, Ac-(PHGGGWGQ)(4)-NH(2), was also investigated by means of Pulse radiolysis. The copper(II) complexes with avian peptides do not display SOD-like activity, while very low activity has been detected for the copper(II) complexes with mammalian tetraoctarepeat.
对铜（II）与鸡朊病毒蛋白N端片段Ac-(PHNPGY)(4)-NH(2)以及突变残基Ac-(PHNPGF)(4)-NH(2)形成的配合物进行了电位滴定和光谱（紫外可见、圆二色和电子顺磁共振）研究，以评估酪氨酸在铜配位中的作用。热力学和光谱结果均表明，鸡朊病毒片段不能结合超过两个铜离子，且只有侧链酪氨酸基团参与其中。在1:1金属与配体比例体系中，主要的配合物显示一个铜离子与四个咪唑氮原子结合。还通过脉冲辐解研究了铜（II）与禽类肽以及哺乳动物类似物Ac-(PHGGGWGQ)(4)-NH(2)形成的配合物的超氧化物歧化酶（SOD）样活性。铜（II）与禽类肽形成的配合物不显示SOD样活性，而铜（II）与哺乳动物四肽重复序列形成的配合物检测到非常低的活性。
