Kowalik-Jankowska Teresa, Ruta-Dolejsz Monika, Wiśniewska Kornelia, Lankiewicz Leszek
Faculty of Chemistry, University of Wroclaw, Joliot-Curie 14, Wroclaw, Poland.
J Inorg Biochem. 2002 Sep 30;92(1):1-10. doi: 10.1016/s0162-0134(02)00495-6.
A potentiometric and spectroscopic (UV-vis, CD and EPR) study of Cu(II) binding to the (11-20), (11-28), (Ac-11-20H) and (Ac-11-28) fragments of human (H) and mouse (M) beta-amyloid peptide was carried out. The values of the protonation constants of the two lysine side chain amino groups for the (11-28) and (Ac-11-28) fragments of beta-amyloid peptide differ noticeably suggesting considerable interactions between the two residues. The N-terminal amino acid sequence Xaa-Yaa-His for the (11-20H) and (11-28H) fragments determines the coordination ability of the fragments studied to copper(II) ions. Addition of the (17-20) and (17-28) sequences to the (11-16) fragment of human and mouse beta-amyloid peptide does not change the coordination mode, and the stabilities of the complexes formed are comparable to those of the (11-16) peptide, although 1N complexes of the (11-28) fragments are stabilized by about one order of magnitude compared to those of the (11-16) peptides. The (Ac-11-28) peptides form complexes with the same coordination mode as those for the (Ac-11-16) fragments. The stability of the complexes for the (Ac-11-28H) fragment is one or two orders of magnitude higher compared to those of the (Ac-11-16H) fragment. This stabilization may result from structural organization of a peptide in copper(II) complexes.
对铜（II）与人（H）和小鼠（M）β-淀粉样肽的（11 - 20）、（11 - 28）、（Ac - 11 - 20H）和（Ac - 11 - 28）片段的结合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。β-淀粉样肽的（11 - 28）和（Ac - 11 - 28）片段的两个赖氨酸侧链氨基的质子化常数值明显不同，表明这两个残基之间存在相当大的相互作用。（11 - 20H）和（11 - 28H）片段的N端氨基酸序列Xaa - Yaa - His决定了所研究片段与铜（II）离子的配位能力。将（17 - 20）和（17 - 28）序列添加到人及小鼠β-淀粉样肽的（11 - 16）片段中，不会改变配位模式，并且形成的配合物的稳定性与（11 - 16）肽的相当，尽管（11 - 28）片段的1N配合物比（11 - 16）肽的稳定约一个数量级。（Ac - 11 - 28）肽形成的配合物与（Ac - 11 - 16）片段的具有相同的配位模式。（Ac - 11 - 28H）片段的配合物稳定性比（Ac - 11 - 16H）片段的高一个或两个数量级。这种稳定性增强可能源于肽在铜（II）配合物中的结构组织。
