超氧化物歧化酶模拟体系铜（II）/乙酰-L-组氨酰甘氨酰-L-组氨酰甘氨酸的光谱和电位研究

Spectroscopic and potentiometric study of the SOD mimic system copper(II)/acetyl-L-histidylglycyl-L-histidylglycine.

作者信息

Casolaro Mario, Chelli Mario, Ginanneschi Mauro, Laschi Franco, Messori Luigi, Muniz-Miranda Maurizio, Papini Anna M, Kowalik-Jankowska T, Kozlowski Henryk

机构信息

Dipartimento di Chimica and Istituto di Chimica dei Composti Organo Metallici del C.N.R., Università di Siena, Pian dei Mantellini 44, Italy.

出版信息

J Inorg Biochem. 2002 Apr 28;89(3-4):181-90. doi: 10.1016/s0162-0134(02)00365-3.

DOI:10.1016/s0162-0134(02)00365-3

PMID:12062121

Abstract

Stoichiometry, stability constants and solution structures of the copper(II) complexes of the N-acetylated tetrapeptide HisGlyHisGly were determined in aqueous solution in the pH range 2-11. The potentiometric and spectroscopic data (UV-Vis, CD, EPR and Raman scattering) show that acetylation of the amino terminal group induces drastic changes in the coordination properties of AcHGHG compared to HGHG. The N3 atoms of the histidine side chains are the first anchoring sites of the copper(II) ion. At pH 4.7 and 5.6 both the imidazole rings cooperate in the formation of a 2N equatorial set, while, at higher pH values, 3N and 4N complexes are formed through the coordination of peptide N- atoms. The logbeta values of the copper complexes of AcHGHG are by far lower than those of the corresponding species in the parent CuII-HGHG system.

摘要

在pH值为2 - 11的水溶液中，测定了N - 乙酰化四肽HisGlyHisGly的铜（II）配合物的化学计量学、稳定常数和溶液结构。电位滴定和光谱数据（紫外可见光谱、圆二色光谱、电子顺磁共振光谱和拉曼散射光谱）表明，与HGHG相比，氨基末端基团的乙酰化导致AcHGHG的配位性质发生了显著变化。组氨酸侧链的N3原子是铜（II）离子的第一个锚定位点。在pH 4.7和5.6时，两个咪唑环协同形成一个2N赤道配位组，而在较高pH值时，通过肽N原子的配位形成3N和4N配合物。AcHGHG的铜配合物的logβ值远低于母体CuII - HGHG体系中相应物种的logβ值。