Prion Proteins with Insertion Mutations Have Altered N-terminal Conformation and Increased Ligand Binding Activity and Are More Susceptible to Oxidative Attack*
Prion Proteins with Insertion Mutations Have Altered N-terminal Conformation and Increased Ligand Binding Activity and Are More Susceptible to Oxidative Attack*
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DOI：
10.1074/jbc.m511819200
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发表时间：
2006-04
影响因子：
4.8
通讯作者：
Shaoman Yin;Shuiliang Yu;Chaoyang Li;Poki Wong;Binggong Chang;F. Xiao;Shin‐Chung Kang;Huimin Yan;Gengfu Xiao;J. Grassi;P. Tien;M. Sy
中科院分区：
文献类型：
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作者：
Shaoman Yin;Shuiliang Yu;Chaoyang Li;Poki Wong;Binggong Chang;F. Xiao;Shin‐Chung Kang;Huimin Yan;Gengfu Xiao;J. Grassi;P. Tien;M. Sy
我们比较了野生型重组正常人类细胞朊病毒蛋白rPrPc与重组突变人类朊病毒蛋白rPrP8OR的生化特性，该蛋白具有三个额外的八肽重复序列。针对rPrPc N端特异性的单克隆抗体与rPrP8OR的反应要比rPrPc好得多，这表明rPrP8OR的N端更暴露，因此更容易被抗体结合。PrPc的N端含有一个糖胺聚糖结合基序。因此，rPrP8OR也比rPrPc结合更多的糖胺聚糖。此外，二价阳离子铜对rPrPc和rPrP8OR构象的调节也不同。与rPrPc相比，rPrP8OR也更容易受到氧化损伤。此外，与rPrP8OR相关的异常在另一个插入突变体rPrP10OR中重现，但更为深刻，该突变体具有5个额外的八肽重复。因此，插入突变体似乎具有共同的特征，并且异常程度与插入次数成正比。这些异常中的任何一种都可能导致遗传性人类朊病毒病的发病机制。
We compared the biochemical properties of a wild type recombinant normal human cellular prion protein, rPrPc, with a recombinant mutant human prion protein that has three additional octapeptide repeats, rPrP8OR. Monoclonal antibodies that are specific for the N terminus of rPrPc react much better with rPrP8OR than rPrPc, suggesting that the N terminus of rPrP8OR is more exposed and hence more available for antibody binding. The N terminus of PrPc contains a glycosaminoglycan binding motif. Accordingly, rPrP8OR also binds more glycosaminoglycan than rPrPc. In addition, the divalent cation copper modulates the conformations of rPrPc and rPrP8OR differently. When compared with rPrPc, rPrP8OR is also more susceptible to oxidative damage. Furthermore, the abnormalities associated with rPrP8OR are recapitulated, but even more profoundly, in another insertion mutant, which has five extra octapeptide repeats, rPrP10OR. Therefore, insertion mutants appear to share common features, and the degree of abnormality is proportional to the number of insertions. Any of these anomalies may contribute to the pathogenesis of inherited human prion disease.