Spectroscopy investigation on conformational transition of tea glycoconjugate from green tea

The conformational transition of a new glycoconjugate, tea glycoconjugate (TGC), was investigated by spectroscopy techniques including circular dichroism (CD) and ultraviolet (UN) spectroscopy. The solution behaviors of TGC in the mediums of different temperature, pH value, and ions were compared. Results showed that the native conformation of TGC was partially ordered. The CD value and UV absorbance of TGC altered with the change of pH value, temperature, the addition of ions, and also accompanied order-disorder transition. Especially the conditions with temperature higher than the glass transition temperature (T_g=62°C), higher pH value or lower pH value will have the most impact on the conformation of TGC, which will destroy the hydrogen bonds between the TGC molecules. The results indicated that the outside factors play important roles on the stability of the conformation of TGC.