红外光谱法研究温度变化对卵粘蛋白构象的影响

Infrared Spectroscopy Analysis of Structural Changes of Ovornucin as Induced by Temperature

采用傅里叶变换红外(FTIR)光谱法和二维相关分析(2D Correlation analysis)技术研究了卵粘蛋白(Ovomucin)的构象转变与温度之间的关系.结果表明,当温度为55～65℃时,卵粘蛋白的红外谱峰的位置和强度发生较大改变.二维相关分析表明,在升温过程中,与肽链相比卵粘蛋白分子中的糖链对温度变化更为敏感,且优先发生构象改变,糖链分子的存在利于维持卵粘蛋白构象的热稳定性.在25～95℃升温过程中,卵粘蛋白分子二级结构的变化次序依次为α-螺旋、β-折叠、β-转角和无规卷曲.由温度变化引起的卵粘蛋白分子结构动态变化的微观信息,为揭示变温微扰引起的蛋白构象变化机理提供了初步的理论依据.

Fourier transform infrared （FFIR） spectroscopy combined with 2D correlation spectroscopy was used to offer some information about the structural stability of ovomucin. Temperature has been chosen as the perturbation to monitor the infrared behavior of ovomucin. The results indicate that the sharp changes in the peak position and the intensity in the infrared spectra of ovomucin occur basically between 55 °C and 65 °C. Two-dimensional correlation analysis further showed that the sugar chain in ovomuein is more sensitive to temperature perturbation than the amide area of peptide since it was more likely to change prior to peptide during the heat treatment. The presence of sugar chain in ovomucin molecule was helpful to maintain the stability of protein conformation. The order of secondary structural changes in ovomucin as induced by temperature was a- helix,β-sheet, β-turn and random coil. These results provide preliminary information about the mechanism of ovomuein eonformational changes as induced by variable temperature perturbation.