Miura T, Hori-i A, Takeuchi H
Pharmaceutical Institute, Tohoku University, Sendai, Japan.
FEBS Lett. 1996 Nov 4;396(2-3):248-52. doi: 10.1016/0014-5793(96)01104-0.
Prion diseases share a common feature in that the normal cellular prion protein (PrP(C)) converts to a protease-resistant isoform PrP(Sc). The alpha-helix-rich C-terminal half of PrP(C) is partly converted into beta-sheet in PrP(Sc). We have examined by Raman spectroscopy the structure of an octapeptide PHGGGWGQ that appears in the N-terminal region of PrP(C) and a longer peptide containing the octapeptide region. The peptides do not assume any regular structure without divalent metal ions, whereas Cu(II) binding to the HGGG segment induces formation of alpha-helical structure on the C-terminal side of the peptide chain. The N-terminal octapeptide of prion protein may be a novel structural motif that acts as a promoter of alpha-helix formation.
朊病毒疾病有一个共同特征，即正常细胞朊病毒蛋白（PrP(C)）会转化为蛋白酶抗性异构体PrP(Sc)。PrP(C)富含α-螺旋的C端一半在PrP(Sc)中部分转化为β-折叠。我们通过拉曼光谱研究了出现在PrP(C) N端区域的八肽PHGGGWGQ以及包含该八肽区域的更长肽段的结构。这些肽段在没有二价金属离子时不呈现任何规则结构，而Cu(II)与HGGG片段结合会诱导肽链C端形成α-螺旋结构。朊病毒蛋白的N端八肽可能是一种新型结构基序，可作为α-螺旋形成的促进剂。
