A novel copper(II) coordination at His186 in full-length murine prion protein

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• 作者：Yasuko Watanabe ; Wakako Hiraoka ; Manabu Igarashi ; Kimihito Ito ; Yuhei Shimoyama ; Motohiro Horiuchi ; Tohru Yamamori ; Hironobu Yasui ; Mikinori Kuwabara ; Fuyuhiko Inagaki ; Osamu Inanami
• 关键词：Prion protein ; Cu(II) ; C-terminal domain ; ESR ; SDSL ; MTSSL ; Interspin distance ; Dipolar interaction ; Histidine residue
• 刊名：Biochemical and Biophysical Research Communications
• 出版年：2010
• 出版时间：9 April 2010
• 年：2010
• 卷：394
• 期：3
• 页码：522-528
• 全文大小：735 K

文摘

To explore Cu(II) ion coordination by His¹⁸⁶ in the C-terminal domain of full-length prion protein (moPrP), we utilized the magnetic dipolar interaction between a paramagnetic metal, Cu(II) ion, and a spin probe introduced in the neighborhood of the postulated binding site by the spin labeling technique (SDSL technique). Six moPrP mutants, moPrP(D143C), moPrP(Y148C), moPrP(E151C), moPrP(Y156C), moPrP(T189C), and moPrP(Y156C,H186A), were reacted with a methane thiosulfonate spin probe and a nitroxide residue (R1) was created in the binding site of each one. Line broadening of the ESR spectra was induced in the presence of Cu(II) ions in moPrP(Y148R1), moPrP(Y151R1), moPrP(Y156R1), and moPrP(T189R1) but not moPrP(D143R1). This line broadening indicated the presence of electron–electron dipolar interaction between Cu(II) and the nitroxide spin probe, suggesting that each interspin distance was within 20 Å. The interspin distance ranges between Cu(II) and the spin probes of moPrP(Y148R1), moPrP(Y151R1), moPrP(Y156R1), and moPrP(T189R1) were estimated to be 12.1 Å, 18.1 Å, 10.7 Å, and 8.4 Å, respectively. In moPrP(Y156R1,H186A), line broadening between Cu(II) and the spin probe was not observed. These results suggest that a novel Cu(II) binding site is involved in His186 in the Helix2 region of the C-terminal domain of moPrP^C.