Biochemistry. 2014 Jun 24;53(24):3934-99. doi: 10.1021/bi500643b.
The cellular prion protein (PrPC) binds to Cu2+ ions in vivo, and a misfolded form of PrPC is responsible for a range of transmissible spongiform encephalopathies. Recently, disruption of Cu2+ homeostasis in mice has been shown to impart resistance to scrapie infection. Using full-length PrPC and model peptide fragments, we monitor the sequential loading of Cu2+ ions onto PrPC using visible circular dichroism. We show the N-terminal amino group of PrPC is not the principal binding site for Cu2+; however, surprisingly, it has an affinity for Cu2+ tighter than that of the individual octarepeat binding sites present within PrPC. We re-evaluate what is understood about the sequential loading of Cu2+ onto the full-length protein and show for the first time that Cu2+ loads onto the N-terminal amino group before the single octarepeat binding sites.
细胞朊病毒蛋白（PrPC）在体内与 Cu2+ 离子结合，而构象错误的 PrPC 是多种传染性海绵状脑病的罪魁祸首。最近，研究表明，破坏小鼠体内的 Cu2+ 稳态可赋予其对瘙痒病感染的抗性。我们使用全长 PrPC 和模型肽片段，使用可见圆二色性监测 Cu2+ 离子依次加载到 PrPC 上的情况。我们表明，PrPC 的 N 端氨基不是 Cu2+ 的主要结合位点；然而，令人惊讶的是，它与 Cu2+ 的亲和力比单个八重复结合位点内存在的 Cu2+ 要强。我们重新评估了对全长蛋白上 Cu2+ 依次加载的理解，并首次表明 Cu2+ 首先加载到 N 端氨基，然后再加载到单个八重复结合位点上。
