Hydrogen bonding between sugar and protein is responsible for inhibition of dehydration-induced protein unfolding
Hydrogen bonding between sugar and protein is responsible for inhibition of dehydration-induced protein unfolding
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DOI：
10.1006/abbi.1999.1175
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发表时间：
1999-05-15
影响因子：
3.9
通讯作者：
Carpenter, JF
中科院分区：
文献类型：
--
作者：
Allison, SD;Chang, B;Carpenter, JF
在脱水过程中，抑制蛋白质展开和随后糖损伤的相互作用的性质尚不清楚。研究了库伦卡尔费歇尔滴定法测定的样品水分含量与红外光谱中约1580 cm（-1）处蛋白质侧链羧酸带面积预测的表观水分含量之间的关系。对于在干燥固体中保留高水平天然蛋白质结构的样品，羧酸带面积预测的表观水分含量大于实际水分含量，表明保护是糖-蛋白质直接氢键的结果，而不是蛋白质表面的水包裹。此外，我们发现蔗糖和海藻糖对结构的保护程度与糖和蛋白质之间氢键的程度有关。右旋糖酐抑制脱水诱导的溶菌酶展开的失败是由于聚合物无法充分与蛋白质形成氢键。因此，在脱水过程中，仅形成无定形相不足以维持蛋白质结构。葡萄糖氢键与干燥的溶菌酶高度结合，但在缺乏有效的冷冻保护剂的情况下无法抑制冻干诱导的蛋白质展开。然而，在冷冻过程中加入聚乙二醇可以保护蛋白质，而不是在干燥过程中保护葡萄糖，在冻干过程中保护溶菌酶的结构。总之，这些结果表明碳水化合物和蛋白质之间的氢键是防止脱水引起的蛋白质损伤所必需的。然而，在没有足够的冷冻保护的情况下，单独的氢键不足以在冻干过程中保护蛋白质。(C) 1999学术出版社。
The nature of the interaction responsible for the inhibition of protein unfolding and subsequent damage by sugars during dehydration is unclear. The relationship between sample moisture content measured by coulometric Karl Fischer titration and the apparent moisture content predicted by the area of the protein side chain carboxylate band at approximately 1580 cm(-1) in infrared spectra of dried protein-sugar samples was examined. For samples in which a high level of native protein structure was retained in the dried solid, the apparent moisture content predicted by the carboxylate band area was greater than the actual moisture content, indicating that protection results from direct sugar-protein hydrogen bonding and not entrapment of water at the protein surface. Further, we show that the degree of structural protection conferred by sucrose and trehalose apparent in second derivative, amide I infrared spectra, correlates with the extent of hydrogen bonding between sugar and protein. The failure of dextran to inhibit dehydration-induced lysozyme unfolding is shown to result from the inability of the polymer to hydrogen bond adequately to the protein. Therefore, formation of an amorphous phase alone is not sufficient to maintain protein structure during dehydration. Glucose hydrogen bonds to a high degree with dried lysozyme, but is incapable of inhibiting lyophilization-induced protein unfolding in the absence of an effective cryo-protectant. However, the addition of polyethylene glycol, which is known to protect proteins during freezing, but not drying, to glucose protected lysozyme structure during lyophilization. Together, these results show that hydrogen bonding between carbohydrate and protein is necessary to prevent dehydration-induced protein damage. However, hydrogen bonding alone is not sufficient to protect proteins during lyophilization in the absence of adequate freezing protection. (C) 1999 Academic Press.