Interaction of the human prion PrP(106-126) sequence with copper(II), manganese(II), and zinc(11): NMR and EPR studies
Interaction of the human prion PrP(106-126) sequence with copper(II), manganese(II), and zinc(11): NMR and EPR studies
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DOI：
10.1021/ja045958z
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发表时间：
2005-01-26
影响因子：
15
通讯作者：
Kozlowski, H
中科院分区：
文献类型：
--
作者：
Gaggelli, E;Bernardi, F;Kozlowski, H
考虑了包含人朊病毒蛋白残基106-126的合成肽（PrP 106 -126，KTNMKHMAGAAAAA-GAVGGLG）在pH 5.7下对铜（II）、锰（II）和锌（II）的结合特性。H-1和C-13一维光谱，H-1自旋-晶格弛豫速率，和H-1-N-15和H-1-C-13 HSQC二维实验中获得的金属离子的存在和不存在。虽然锌（II）被发现产生任何NMR参数的影响可以忽略不计，金属-肽协会被证明是由顺磁效应的Cu（II）和Mn（II）的1D和2D光谱。通过解释顺磁效应对H-1自旋-晶格弛豫速率的影响来描述金属配合物的结构。肽分子从金属配位球的交换被证明提供了相当大的贡献所观察到的弛豫速率。这种贡献的情况下计算的Cu（II），而更快的顺磁速率结合到Mn（II）的肽分子决定自旋晶格弛豫速率几乎完全由交换占主导地位。因此，质子-金属的距离进行了评估的情况下，仅Cu（II）配合物，并作为限制在分子动力学计算，从那里得到的结构的配合物。该肽被证明通过咪唑氮和电离的酰胺氮的His-111和氨基末端基团与稳定的配位球通过离子相互作用的末端羧基结合铜。对数据进行解释，以证明疏水C-末端区域不影响肽的铜结合特性，并且该疏水尾部自由地与其他靶分子相互作用。至于与Mn（II）的复合物，获得定性信息上的羰基氧的Gly-124和Leu-125，超出了末端Gly-126羧基，在近距离的金属离子，也相互作用，最有可能的是，通过氢键的金属结合水，与咪唑环的His-111。
The synthetic peptide encompassing residues 106-126 (PrP106-126, KTNMKHMAGAAAA-GAVVGGLG) of the human prion protein was considered for its binding properties toward copper(II), manganese(II) and zinc(II) at pH 5.7. H-1 and C-13 1D spectra, H-1 spin-lattice relaxation rates, and H-1-N-15 and H-1-C-13 HSQC 2D experiments were obtained in the absence and in the presence of metal ions. While Zn(II) was found to yield negligible effects upon any NMR parameter, metal-peptide association was demonstrated by the paramagnetic effects of Cu(II) and Mn(II) upon 1D and 2D spectra. Delineation of structures of metal complexes was sought by interpreting the paramagnetic effect on H-1 spin-lattice relaxation rates. Exchange of peptide molecules from the metal coordination sphere was shown to provide sizable contribution to the observed relaxation rates. Such contribution was calculated in the case of Cu(II); whereas the faster paramagnetic rates of peptide molecules bound to Mn(II) were determining spin-lattice relaxation rates almost exclusively dominated by exchange. Proton-metal distances were therefore evaluated in the case of the Cu(II) complex only and used as restraints in molecular dynamics calculations wherefrom the structure of the complex was obtained. The peptide was shown to bind copper through the imidazole nitrogen and the ionized amide nitrogen of His-111 and the amino-terminal group with the terminal carboxyl stabilizing the coordination sphere through ionic interactions. The data were interpreted as to demonstrate that the hydrophobic C-terminal region was not affecting the copper-binding properties of the peptide and that this hydrophobic tail is left free to interact with other target molecules. As for the complex with Mn(II), qualitative information was obtained on carbonyl oxygens of Gly-124 and Leu-125, beyond the terminal Gly-126 carboxyl, being at close distance from the metal ion, that also interacts, most likely, through a hydrogen bond of metal-bound water, with the imidazole ring of His-111.