质子化作用对Aβ_(1—16)单体结构特征和聚集机理的影响  

Effect of Protonation on Structural Characteristics and Aggregation Mechanisms of β-Amyloid(1—16) Peptide

作　　者：石虎[1] 程珊珊[1] 艾洪奇[1] 

机构地区：[1]济南大学化学化工学院,济南250022

出　　处：《高等学校化学学报》2013年第5期1214-1218,共5页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:20973084);国家自然科学基金与韩国国家研究基金(批准号:21211140340);山东省自然科学基金(批准号:Y2008B56)资助

摘　　要：利用副本交换分子动力学模拟研究了Aβ肽(β-Amyloid peptide)N末端部分Aβ1—16单体在pH为7.0,6.3及5.5水溶液状态下的结构特征以及聚集机理.通过建模确定了不同pH状态下Aβ1—16肽链的质子化位置(残基),通过模拟比较了不同酸性溶液状态下Aβ1—16单体的结构和能量变化.结果表明,在中性条件下,Aβ1—16单体保持自由卷曲结构,而在酸性状态下,其结构由最初的无序状态向有序状态转变,模拟过程中β-折叠结构会间歇性产生,预示着单体可以发生自聚集现象.本文所得结论,即酸性状态下的Aβ1—16单体质子化位及模拟过程中的结构变化,可用于酸性状态下金属离子与Aβ1—16可能的残基结合位及结合数量的有效预测和评估.Structural characteristics and aggregation mechanisms of A/β1-16 fragment under different conditions of pH = 7.0, 6.3 and 5.5 were studied by replica exchange molecular dynamics （REMD）. The results show that protonated residues and number of A/β1-16 depend on the difference of pH. Structural changes indicate that A/β1-16 has a transitional trend from the disordered state to the ordered one along with the increase of acidic concentration. β-Sheet intermittently appears in acidic conditions during the simulations, implying that A/β1-16 tends to self-aggregation in such case. The protonated positions and structural changes picted in the present work can be employed to predict and assess the potential binding tion numbers for a transition metal ion to approach the monomer. of monomer de- positions and coordination numbers for a transition metal ion to approach the monomer.

关 键 词：分子动力学模拟 Aβ1—16 质子化作用 结构特征 聚集 

分 类 号：O641.121[理学—物理化学]