NMR analysis of synthetic human serum albumin α-helix 28 identifies structural distortion upon amadori modification
NMR analysis of synthetic human serum albumin α-helix 28 identifies structural distortion upon amadori modification
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DOI：
10.1074/jbc.m501480200
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发表时间：
2005-06-17
影响因子：
4.8
通讯作者：
Smales, CM
中科院分区：
文献类型：
--
作者：
Howard, MJ;Smales, CM
体内还原糖和长寿命蛋白质之间的非酶促反应导致糖基化和晚期糖基化终产物的形成，其改变蛋白质的性质，包括电荷、螺旋度及其聚集趋势。这种蛋白质修饰与一般衰老过程相关的各种病理学有关，如阿尔茨海默病和糖尿病的长期并发症。虽然它已被建议，糖化和晚期糖化终产物改变蛋白质的结构和螺旋度，很少的结构数据和信息，目前存在的糖化是否确实影响或改变局部蛋白质二级结构。我们已经解决了这个问题，使用模型螺旋肽系统含有来自人血清白蛋白的二赖氨酸基序。我们已经表明，在50 mM葡萄糖存在下，在37 ℃下，该肽内的二赖氨酸基序中的一个赖氨酸残基优先被糖化。使用NMR分析，我们已经证实，在30%三氟乙醇存在下，构成该螺旋的合成肽确实在溶液中形成α-螺旋。模型肽的糖化导致α-螺旋的扭曲，迫使糖化位点周围的螺旋区域采用3（10）螺旋结构。这是第一个报道的证据表明，糖基化可以影响或改变局部蛋白质二级结构。这种结构变化对蛋白质功能的影响和生物学意义进行了讨论。
The non-enzymatic reaction between reducing sugars and long-lived proteins in vivo results in the formation of glycation and advanced glycation end products, which alter the properties of proteins including charge, helicity, and their tendency to aggregate. Such protein modifications are linked with various pathologies associated with the general aging process such as Alzheimer disease and the long-term complications of diabetes. Although it has been suggested that glycation and advanced glycation end products altered protein structure and helicity, little structural data and information currently exist on whether or not glycation does indeed influence or change local protein secondary structure. We have addressed this problem using a model helical peptide system containing a di-lysine motif derived from human serum albumin. We have shown that, in the presence of 50 mM glucose and at 37 degrees C, one of the lysine residues in the di-lysine motif within this peptide is preferentially glycated. Using NMR analysis, we have confirmed that the synthetic peptide constituting this helix does indeed form a alpha-helix in solution in the presence of 30% trifluoroethanol. Glycation of the model peptide resulted in the distortion of the alpha-helix, forcing the region of the helix around the site of glycation to adopt a 3(10) helical structure. This is the first reported evidence that glycation can influence or change local protein secondary structure. The implications and biological significance of such structural changes on protein function are discussed.