圆二色谱分析抗氧化剂EGb761配伍TA9901对老化Aβ_(1-42)二级结构改变的影响

Antioxidant EGb761 matched TA9901 changes secondary conformation of amyloid-β-peptide_( 1-42) by circular dichroism spectrum

目的 研究抗氧化剂EGb76 1、TA990 1及EGb76 1配伍TA990 1抑制Aβ1-42 聚集作用的分子机制。方法 运用圆二色谱 (CD)分析Aβ1-42 老化后以及其与EGb76 1、TA990 1和二者配伍物共同孵育后二级结构变化。结果 Aβ1-42 孵育 30min和 2 4h及用EGb76 1、TA990 1和其配伍物干预后 ,Aβ1-42 的CD图形发生了明显改变 ,30min以不规则卷曲和α 螺旋为主 ,其含量分别为 4 0 5 %和 2 5 4 % ;孵育 2 4h后以 β 折叠为主 ,占 4 0 3% ;TA990 1、EGb76 1和配伍物分别与Aβ1-42 共同作用后 ,则α 螺旋结构增多 ,分别为 37 6 %、4 5 3%和 10 0 % ,β 折叠消失。 结论 EGb76 1配伍TA990 1及其成分均能促使老化的Aβ1-42 由 β 折叠向α 螺旋转化 。

Objective To investigate molecular mechanism of antioxidant TA9901, EGb761 and their matched ingredient inhibiting aggregation and fibril formation of amyloid β peptide (Aβ) 1-42 .Method By using of circular dichroism(CD) spectrum analyses, the secondary conformation of Aβ incubated 30min,24h and Aβ with TA9901,EGb761 and TA9902 were observed respectively.Results Spectroscopy analyses indicated that unorder coil and α helix were dominating for 30min, unorder coil and α helix were 40 5%,25 4% respectively,β sheet formation was significantly present for 24h, up to 40.3%.However, when coexist with TA9901,EGb761 or EGb761 matched TA9901, the spectra showed the tendency of α helix. The calculation showed that α helix were 37 6%,45 3% and 100% respectively, none β sheet formation.Conclusion EGb761 matched TA9901,EGb761 and TA9901 have intervention in β sheet formation of Aβ,and can change β sheet structure into α helix conformation, But the compound ingredient are best.