Amani Samreen, Shamsi Anas, Rabbani Gulam, Naim Aabgeena
Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh, 202002, India.
J Fluoresc. 2014 Sep;24(5):1423-31. doi: 10.1007/s10895-014-1424-x. Epub 2014 Jul 11.
Misfolding and aggregation of proteins is involved in some of the most prevalent neurodegenerative disorders. The importance of collagen stems from the fact that it is one of the dominant component used for tissue engineering and drug delivery applications and is a major component of skin, tendon, bone and other connective tissues. A systematic investigation on the conformation of collagen at various concentrations of glyoxal is studied by various biophysical techniques such as Trp fluorescence, ANS binding, Circular dichroism (CD), ATR-FTIR, Congo red (CR) assay, Rayleigh light scattering and Turbidity measurements. At 60% (v/v) glyoxal, collagen retains native-like secondary structure, altered Trp environment and high ANS fluorescence, characteristic of molten globule (MG) state. At 80% (v/v) glyoxal, insoluble collagen aggregates are detected as confirmed by decrease in Trp and ANS fluorescence, increase in non-native β sheet structure as evident from far-UV CD and FTIR spectra, increase in Thioflavin T fluorescence, Rayleigh light scattering, Turbidity measurements, as well as red shift in CR absorbance.
蛋白质的错误折叠和聚集与一些最常见的神经退行性疾病有关。胶原蛋白的重要性源于这样一个事实，即它是用于组织工程和药物递送应用的主要成分之一，并且是皮肤、肌腱、骨骼和其他结缔组织的主要成分。通过各种生物物理技术，如色氨酸荧光、ANS结合、圆二色性（CD）、衰减全反射傅里叶变换红外光谱（ATR-FTIR）、刚果红（CR）测定、瑞利光散射和浊度测量，对不同乙二醛浓度下胶原蛋白的构象进行了系统研究。在60%（v/v）乙二醛浓度下，胶原蛋白保留了类似天然的二级结构，色氨酸环境发生改变，ANS荧光较高，这是熔球态（MG）的特征。在80%（v/v）乙二醛浓度下，检测到不溶性胶原蛋白聚集体，这通过色氨酸和ANS荧光的降低、远紫外CD和FTIR光谱中明显的非天然β片层结构增加、硫黄素T荧光增加、瑞利光散射、浊度测量以及CR吸光度的红移得到证实。
