朊蛋白是铜结合蛋白,而铜离子介导了朊蛋白的二级结构变化,使其聚沉在中枢神经系统中,导致传染性海绵状脑病.重组人朊蛋白91—231截去了八肽重复区域,利用X射线吸收谱近边结构解析出了C端高亲和性的铜结合位点的三维精细结构.结果显示与兔朊蛋白相比人朊蛋白中氨基酸与铜结合更紧密.本研究可能揭示了不同物种对传染性海绵状脑病具有不同抗性的原因.
Prion protein is considered to be a copper-related protein, and the copper ion induces the secondary structure changes of prion proteins, making them aggregate and deposit in the central nervous system, and causing transmissible spongiform eneephalopathies (TSE). The three-dimensional fine structure of C-terminal high-affinity eopper binding site was determined in recombinant human prion 91-231 (HuPrP91-231), which lacks the octapeptide repeat region, using X-ray absorption near-edge structure (XANES) combined with the ab initio calculations in the framework of the multiple-scattering theory. Results show that amino acid residues have closer distances from the copper ion compared with those of the rabbit prion. This might be the reason why different species have different immunities to TSE.