Ⅱ型胶原蛋白的热稳定性、圆二色性和红外光谱研究

Studies on thermostability,circular dichroism and Infrared spectral characteristics of type Ⅱ collagen

目的以蓝鲨Ⅱ型胶原蛋白为材料,分析Ⅱ型胶原蛋白的热稳定性、圆二色性和红外光谱特性。方法采用限制性酶解法分离蓝鲨软骨Ⅱ型胶原蛋白,通过SDS-PAGE、DSC、CD、IR分析Ⅱ型胶原蛋白的相对分子质量、热变性温度、二级结构特征和红外光谱特征。结果蓝鲨Ⅱ型胶原蛋白是由相对分子质量为130kDa的α1链构成;蓝鲨Ⅱ型胶原蛋白的热变性温度为40.5℃,[Na+]和[H+]改变了胶原蛋白的热稳定性;蓝鲨Ⅱ型胶原蛋白在3411、3008、1648、1549cm-1有红外特征性吸收峰;蓝鲨Ⅱ型胶原蛋白以β-折叠为主,占主链的36.9%,接近于全β型三级结构,[H+]将改变Ⅱ型胶原蛋白的二级结构元件构成,使其β-折叠消失,出现少量的α-螺旋,Ⅱ型胶原蛋白肽链转变成无规卷曲。结论蓝鲨Ⅱ型胶原蛋白是典型的纤维状蛋白质,具有作为生物功能物质的优良生物化学特性。

Objective To study the thermostability, qircular dichroism and infrared spectral characteristics of type Ⅱ collagen purified from cartilage of Prionace glauca. Methods The digestion of pepsin was ap plied to extract type Ⅱ collagen from Prionace glauca cartilage. SDS-PAGE,DSC,CD andlR were used to analyze type Ⅱ collagen relative molecular mass,thermal denaturation temperature,secondary structure and infrared spectral characteristics respectively. Results The type Ⅱ collagen from Prionace glauca was composed of al chains with relative molecular mass 130kDa. The thermal denaturation tempera ture of Prionace glauca type Ⅱ collagen was 40. 5 ℃, and [Na4 ] and [H＋] could alter its thermosta bility. IR analysis indicated that the characteristic absorption peaks of Prionace glauca type H collagen were at 3411,3008,1648 and 1549cm^-1. β-sheet was the main secondary structure of Prionace glauca type Ⅱ collagen, and its ratio was 36.9Y00, which was close to all-β-type tertiary structure. [H＋ ] could change its secondary structure element ratio. With the additive amount of [H＋], β-sheet disappeared and a small number of a-helix appeared, meanwhile, the main secondary structure became random coil. Conclusion The type H collagen purified from Prionace glauca was a typical fibrous protein with excel lent biochemical characteristics as a potential functional biomaterial.