pTTR (transthyretin), a β-sheet-rich protein, is the precursor protein of familial amyloidotic polyneuropathy and senile systemic amyloidosis. Although it has been widely accepted that protein misfolding of the monomeric form of TTR is a rate-limiting step for amyloid formation, no effective therapy targeting this misfolding step is available. In the present study, we focused on CyDs (cyclodextrins), cyclic oligosaccharides composed of glucose units, and reported the inhibitory effect of CyDs on TTR amyloid formation. Of various branched β-CyDs, GUG-β-CyD [6-iO/i-α-(4-iO/i-α-D-glucuronyl)-D-glucosyl-β-CyD] showed potent inhibition of TTR amyloid formation. Far-UV CD spectra analysis showed that GUG-β-CyD reduced the conformational change of TTR in the process of amyloid formation. In addition, tryptophan fluorescence and sup1/supH-NMR spectroscopy analyses indicated that GUG-β-CyD stabilized the TTR conformation via interaction with the hydrophobic amino acids of TTR, especially tryptophan. Moreover, GUG-β-CyD exerted its inhibitory effect by reducing TTR deposition in transgenic rats possessing a human variant iTTR/i gene iin vivo/i. Collectively, these results indicate that GUG-β-CyD may inhibit TTR misfolding by stabilizing its conformation, which, in turn, suppresses TTR amyloid formation./p
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机译:TTR(运甲状腺素蛋白),一种富含β-折叠的蛋白,是家族性淀粉样变性多发性神经病和老年系统性淀粉样变性病的前体蛋白。尽管已经普遍认为,TTR单体形式的蛋白质错误折叠是淀粉样蛋白形成的限速步骤,但没有针对该错误折叠步骤的有效疗法。在本研究中,我们集中于CyDs(环糊精),由葡萄糖单元组成的环状寡糖,并报道了CyDs对TTR淀粉样蛋白形成的抑制作用。在各种分支的β-CyDs中,GUG-β-CyD[6- O i>-α-(4- O i>-α-D-葡萄糖醛酸基)-D-葡萄糖基-β -CyD]显示出对TTR淀粉样蛋白形成的有效抑制作用。远紫外CD光谱分析表明,GUG-β-CyD减少了淀粉样蛋白形成过程中TTR的构象变化。此外,色氨酸荧光和 1 sup> H-NMR光谱分析表明,GUG-β-CyD通过与TTR的疏水性氨基酸(尤其是色氨酸)相互作用来稳定TTR构象。此外,GUG-β-CyD通过降低体内具有人变体 TTR i>基因的转基因大鼠的TTR沉积而发挥其抑制作用。总之,这些结果表明,GUG-β-CyD可以通过稳定其构象来抑制TTR错折叠,进而抑制TTR淀粉样蛋白的形成。 p>
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