Insulin amyloid fibrillation at above 100°C:: New insights into protein folding under extreme temperatures
Insulin amyloid fibrillation at above 100°C:: New insights into protein folding under extreme temperatures
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DOI：
10.1110/ps.04823504
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发表时间：
2004-09-01
期刊：
影响因子：
8
通讯作者：
Park, CB
中科院分区：
文献类型：
--
作者：
Arora, A;Ha, C;Park, CB
为了研究淀粉样蛋白在极端温度下的折叠行为，研究了牛胰岛素在最高至140摄氏度温度范围内的原纤化动力学和伴随的二级结构转变。极端热应激的存在。传统上与蛋白质的不可逆变性有关，而这种变性过程的初始步骤可能与淀粉样蛋白的原纤维形成途径相同。目前的工作证明了胰岛素在100 ℃以上形成淀粉样纤维的能力。淀粉样蛋白的形成在80 ℃后逐渐被无规卷曲的形成所取代，直到在140 ℃没有检测到淀粉样蛋白。随着温度的升高，胰岛素淀粉样纤维的形态发生了急剧的变化。淀粉样蛋白形成速率对孵育温度的依赖性遵循非Arrhenius动力学，这可以用淀粉样蛋白形成的温度依赖性焓变来解释。淀粉样蛋白形成和无规卷曲生成的中间阶段由两种途径共同的部分折叠的中间体组成。当在140 ℃下形成并在100 ℃下孵育时，无规卷曲构象中完全未折叠的单体通过该中间体通过回复到淀粉样蛋白途径而显示出部分可逆性。这项研究强调了极端温度下淀粉样蛋白原纤化的非Arrhenius动力学，并阐明了其与无规卷曲形成共同的中间阶段。
To investigate the folding behavior of amyloidogenic proteins under extreme temperatures, the kinetics of fibrillation and accompanying secondary structure transitions of bovine insulin were studied for temperatures ranging tip to 140degreesC. The presence of extreme heat stress had. traditionally been associated with irreversible denaturation of protein while the initial steps of such a denaturation process may be common with a fibril formation pathway of amyloidogenic proteins. The present work demonstrates the ability of insulin to form amyloid fibrils at above 100degreesC. Amyloid formation was gradually replaced by random coil generation after similar to80degreesC until no amyloid was detected at 140degreesC. The morphology of insulin amyloid fibrils underwent sharp changes with increasing the temperature. The dependence of amyloid formation rate on incubation temperature followed non-Arrhenius kinetics, which is explained by temperature-dependent enthalpy change for amyloid formation. The intermediate stage of amyloid formation and random coil generation consisted of a partially folded intermediate common to both pathways. The fully unfolded monomers in random coil conformation showed partial reversibility through this intermediate by reverting back to the amyloid pathway when formed at 140degreesC and incubated at 100degreesC. This Study highlights the non-Arrhenius kinetics of amyloid fibrillation under extreme temperatures, and elucidates its intermediate stage common with random coil formation.