Takano Kazufumi, Katagiri Yoshiaki, Mukaiyama Atsushi, Chon Hyongi, Matsumura Hiroyoshi, Koga Yuichi, Kanaya Shigenori
Department of Material and Life Science, Osaka University, Suita, Japan.
Proteins. 2007 Aug 15;68(3):617-25. doi: 10.1002/prot.21451.
Certain sequences, known as chameleon sequences, take both alpha- and beta-conformations in natural proteins. We demonstrate that a wild chameleon sequence fused to the C-terminal alpha-helix or beta-sheet in foreign stable proteins from hyperthermophiles forms the same conformation as the host secondary structure. However, no secondary structural formation is observed when the sequence is attached to the outside of the secondary structure. These results indicate that this sequence inherently possesses an ability to make either alpha- or beta-conformation, depending on the sequentially neighboring secondary structure if little other nonlocal interaction occurs. Thus, chameleon sequences take on a satellite state through contagion by the power of a secondary structure. We propose this "conformational contagion" as a new nonlocal determinant factor in protein structure and misfolding related to protein conformational diseases.
某些序列，即所谓的变色龙序列，在天然蛋白质中同时具有α-和β-构象。我们证明，与嗜热菌来源的外源稳定蛋白质的C端α-螺旋或β-折叠融合的野生变色龙序列会形成与宿主二级结构相同的构象。然而，当该序列连接到二级结构外部时，未观察到二级结构的形成。这些结果表明，如果几乎没有其他非局部相互作用发生，该序列本身具有根据相邻二级结构形成α-或β-构象的能力。因此，变色龙序列通过二级结构的作用通过“感染”呈现卫星状态。我们提出这种“构象感染”作为蛋白质结构以及与蛋白质构象疾病相关的错误折叠中的一种新的非局部决定因素。
