不同处理条件对马铃薯糖蛋白Patatin构象的影响研究
Effect of different treatment conditions on the conformation changes of Patatin
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摘要: 运用荧光和圆二色光谱手段研究了不同物理和化学条件处理后,马铃薯糖蛋白Patatin二级和三级结构的变化。结果表明:当p H45时,Patatin的二级结构以α-螺旋为主。当p H69时,Patatin的二级结构以β-折叠为主;随着p H增加,荧光强度下降,最大发射波长蓝移,并且p H对Patatin结构的影响是可逆的;在温度为2060℃时,Patatin的二级结构以β-折叠结构为主,当温度达到80℃时,Patatin的二级结构以无规则卷曲结构为主;随着温度升高,荧光强度下降,最大发射波长红移;当Patatin处于不同浓度的DTT环境时荧光强度下降,当Patatin处于不同浓度的尿素环境时荧光强度增加,出现红移。在变性剂存在条件下,无规则卷曲结构逐渐取代β-折叠结构成为含量最多的构型。Abstract: In this study, the tertiary and secondary structures of Patatin under different physico-chemical treatments were investigated by fluorescence and circular dichrosim. Patatin was rich in α-helix at p H4 ~ 5, but the α-helix was gradually instead by the β-sheet at p H69.With the increasing p H, the strength of fluorescence became apparently lower.A blue shift in the maximum emission wavelength was observed, and the effect of p H on struction was reversible. Patatin was rich in β-sheet from 20 ℃ to 60 ℃.When the temperature reached to 80 ℃, the random coil content reached to maximum.With the increasing temperature, the fluorescence intensity decreased signifcantly. A red shift in the maximum emission wavelength was observed and the fluorescence intensity decreased in Patatin treated by DTT but increased by urea.A red shift in the maximum emission wavelength was observed, and the β-sheet gradually instead by the random coil under the condition of DTT and urea.
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