采用二维红外技术研究交联对碱溶胶原结构的影响

以N-羟基琥珀酰亚胺己二酸酯(NHS-AA)为交联剂,交联改性碱溶胶原,采用二维红外相关光谱法研究了交联对胶原二级结构的影响。研究发现,交联未影响胶原红外特征吸收峰的位置,但1672、1554和1241cm-1归属于胶原酰胺I带的CO伸缩振动、酰胺Ⅱ带的C—N伸缩与N—H弯曲振动和Ⅲ带的N—H面内变形振动峰之间存在同步正交叉峰,表明随交联共价键的增加,胶原的链段构象发生了变化。在NHS-AA用量增加的过程中,胶原二级结构变化的顺序为:酰胺Ⅲ带>酰胺Ⅰ带>酰胺Ⅱ带>—CH3>—CH—。由此可见,二维红外相关分析法能提供由交联引起的胶原构象动态变化的微观信息,为进一步研究改性胶原结构与功能之间的关系提供实验依据。

Effect of cross-linking on the conformation of collagen by two-dimensional infrared correlation spectroscopy

Alkali-solubilized collagen solution cross-linked with N-hydroxysuccinimide activated adipic acid(NHS-AA) ester.The effect of NHS-AA on the secondary structure of alkali-solubilized collagen was examined.The infrared bands,determined by the Fourier-transform infrared spectroscopy(FT-IR),did not reflect characteristics which were caused the amount of cross-linking,but the results from two-dimensional infrared correlation spectroscopy(2D-IR) indicated that the positive synchronous cross-peaks,derived from stretching vibrations of C=O at 1672cm-1,C—N stretching vibrations and wagging of N—H at 1554cm-1 and in plane deformation of N—H at 1241cm-1 of collagen,were indicative of local conformational changes of collagen with increasing cross-linking.The order of secondary structure changes of cross-linked collagen was amide Ⅲ than amide Ⅰ than amide Ⅱ than —CH3 than —CH—.It was shown that the microcosmic information of a change in dynamic structure could be provided for cross-linked collagen with the interruption of the cross-linker concentration.These fundamental data should provide available information for understanding of the relationship between the structure and function of cross-linked collagen.