Strain-dependent differences in β-sheet conformations of abnormal prion protein
Strain-dependent differences in β-sheet conformations of abnormal prion protein
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DOI：
10.1074/jbc.273.48.32230
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发表时间：
1998-11-27
影响因子：
4.8
通讯作者：
Bessen, RA
中科院分区：
文献类型：
--
作者：
Caughey, B;Raymond, GJ;Bessen, RA
传染性海绵状脑病（TSE）的菌株多样性被认为是由异常的朊病毒蛋白（PrP-res）的蛋白酶抗性形式的构象变化决定的。我已经研究了用三种TSE菌株感染仓鼠是否导致使用有限的蛋白酶K（PK）消化和红外光谱形成具有不同构象的PrP-res。从感染hyper（HY）、drowsy（DY）和263 K TSE菌株的仓鼠脑中分离的PrP-res在PK处理前产生了相似的SDS-聚丙烯酰胺凝胶电泳图谱。然而，在有限的消化与PK，PrP-res从DY菌株表现出的片段化模式，这是不同于其他两个菌株。在用PK消化之前和之后，HY和263 K PrP-res的红外光谱均在1626和1636 cm（-1）处的酰胺I区域具有主要吸收带。这些谱带在DY PrP-res光谱中不明显，其在1629-1630 cm（-1）处具有独特谱带，在1616和1694-1695 cm（-1）处具有更强的谱带强度。由于1616 ~ 1636 cm（-1）的红外光谱主要由β-折叠结构引起，这些结果表明HY和263 K PrP-res的构象至少在β-折叠二级结构区域与DY PrP-res不同。这些结果支持的假设，菌株特异性PrP-res构象可以自我繁殖的正常朊病毒蛋白转化为异常构象，诱导表型不同的TSE疾病。
Strain diversity in the transmissible spongiform encephalopathies (TSEs) has been proposed to be determined by variations in the conformation of the abnormal, protease-resistant form of prion protein (PrP-res). me have investigated whether infection of hamsters with three TSE strains resulted in the formation of PrP-res with different conformations using limited proteinase K (PK) digestion and infrared spectroscopy. PrP-res isolated from the brains of hamsters infected with the hyper (HY), drowsy (DY), and 263K TSE strains yielded similar SDS-polyacrylamide gel electrophoresis profiles prior to PK treatment. However, after limited digestion with PK, the PrP-res from the DY strain exhibited a fragmentation pattern that was distinct from that of the other two strains. Infrared spectra of HY and 263K PrP-res each had major absorption bands in the amide I region at 1626 and 1636 cm(-1) both prior to and after digestion with PK. These bands were not evident in the DY PrP-res spectra, which had a unique band at 1629-1630 cm(-1) and stronger band intensity at both 1616 and 1694-1695 cm(-1). Because absorbances from 1616 to 1636 cm(-1) of protein infrared spectra are attributed primarily to beta-sheet structures, these findings indicate that the conformations of HY and 263K PrP-res differ hom DY PrP-res at least in structural regions with beta-sheet secondary structure. These results support the hypothesis that strain-specific PrP-res conformers can self-propagate by converting the normal prion protein to the abnormal conformers that induce phenotypically distinct TSE diseases.