Zatta Paolo, Messori Luigi, Mauri Pierluigi, van Rensburg Susan J, van Zyl Johann, Gabrielli Silvia, Gabbiani Chiara
CNR-Institute for Biomedical Technologies, "Metalloproteins" Unit, Department of Biology, University of Padova, Vle G. Colombo, 3, 3512 Padova, Italy.
Biochim Biophys Acta. 2005 Sep 25;1741(3):264-70. doi: 10.1016/j.bbadis.2005.04.009.
The tryptic digests of blood samples obtained from transferrin C1 and C2 (TfC 1 and TfC2 hereafter) genotypes were analysed by Liquid Chromatography coupled to Electrospray Mass Spectrometry (LC/ESI--MS/MS). The analytical results confirmed the single base change in exon 15 of the Tf gene. The solution behaviour and the iron binding properties of the two Tf variants were studied by UV-visible spectrophotometry and by circular dichroism. It appears that TfC2 globally manifests the same spectral features as the native protein. The local conformation of the two iron binding sites is conserved in the two Tf variants as evidenced by the visible absorption and CD spectra. Also, the iron binding capacities and their pH-dependent profiles are essentially the same. Overall, our investigation points out that the single amino acid substitution in TfC2 (Pro 570 Ser) does not affect the general conformation of the protein nor the local structure of the iron binding sites. The implications of these results for the etiopathogenesis of Alzheimer's disease are discussed.
对从转铁蛋白C1和C2（以下简称TfC 1和TfC2）基因型获得的血样胰蛋白酶消化物进行了液相色谱-电喷雾质谱联用分析（LC/ESI-MS/MS）。分析结果证实了Tf基因第15外显子中的单碱基变化。通过紫外可见分光光度法和圆二色性研究了两种Tf变体的溶液行为和铁结合特性。似乎TfC2总体上表现出与天然蛋白质相同的光谱特征。可见吸收光谱和圆二色光谱证明，两种铁结合位点的局部构象在两种Tf变体中是保守的。此外，铁结合能力及其pH依赖性曲线基本相同。总体而言，我们的研究指出，TfC2中的单个氨基酸取代（Pro 570 Ser）不会影响蛋白质的总体构象，也不会影响铁结合位点的局部结构。讨论了这些结果对阿尔茨海默病病因学的影响。
