Distinct effects of Cu2+-binding on oligomerization of human and rabbit prion proteins.
The cellular prion protein (PrP(C)) is a kind of cell-surface Cu(2+)-binding glycoprotein. The oligomerization of PrP(C) is highly related to transmissible spongiform encephalopathies (TSEs). Cu(2+) plays a vital role in the oligomerization of PrP(C), and participates in the pathogenic process of TSE diseases. It is expected that Cu(2+)-binding has different effects on the oligomerization of TSE-sensitive human PrP(C) (HuPrP(C)) and TSE-resistant rabbit PrP(C) (RaPrP(C)). However, the details of the distinct effects remain unclear. In the present study, we measured the interactions of Cu(2+) with HuPrP(C) (91-230) and RaPrP(C) (91-228) by isothermal titration calorimetry, and compared the effects of Cu(2+)-binding on the oligomerization of both PrPs. The measured dissociation constants (Kd) of Cu(2+) were 11.1 ± 2.1 μM for HuPrP(C) and 21.1 ± 3.1 μM for RaPrP(C). Cu(2+)-binding promoted the oligomerization of HuPrP(C) more significantly than that of RaPrP(C). The far-ultraviolet circular dichroism spectroscopy experiments showed that Cu(2+)-binding induced more significant secondary structure change and increased more β-sheet content for HuPrP(C) compared with RaPrP(C). Moreover, the urea-induced unfolding transition experiments indicated that Cu(2+)-binding decreased the conformational stability of HuPrP(C) more distinctly than that of RaPrP(C). These results suggest that RaPrP(C) possesses a low susceptibility to Cu(2+), potentially weakening the risk of Cu(2+)-induced TSE diseases. Our work sheds light on the Cu(2+)-promoted oligomerization of PrP(C), and may be helpful for further understanding the TSE-resistance of rabbits.
Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing 21009, China.
Kejiang
K
Lin
Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing 21009, China.
Ziyao
Z
Yu
High-field NMR Research Center, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
Yuanhui
Y
Yu
High-field NMR Research Center, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
Xinli
X
Liao
High-field NMR Research Center, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
Pei
P
Huang
High-field NMR Research Center, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China dhlin@xmu.edu.cn guochy78@xmu.edu.cn.
Chenyun
C
Guo
Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing 21009, China High-field NMR Research Center, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China dhlin@xmu.edu.cn guochy78@xmu.edu.cn.
Donghai
D
Lin
D000818:Animals; D001665:Binding Sites; D003198:Computer Simulation; D003300:Copper / Q000737:chemistry*; D019281:Dimerization; D006801:Humans; D008956:Models, Chemical; D008958:Models, Molecular; D018621:PrPC Proteins / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D011817:Rabbits; D013045:Species Specificity
D018621:PrPC Proteins; D003300:Copper
Cu2+; TSE-resistance; affinity; conformational stability; prion oligomerization