Hossein Haghaei
1 
, Seyed Rafie Aref Hosseini
1 , Somaieh Soltani
2, Farzaneh Fathi
3 , Farzad Mokhtari
4 , Saeed Karima
4 , Mohammad-Reza Rashidi
2,3* 1 Nutrition and Food Sciences Faculty, Tabriz University of Medical Sciences, Tabriz, Iran
2 Pharmacy Faculty, Tabriz University of Medical Sciences, Tabriz, Iran
3 Research Center for Pharmaceutical Nanotechnology, Tabriz University of Medical Sciences, Tabriz, Iran
4 Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
Abstract
Introduction: Beta-Boswellic acid (BBA) is a pentacyclic terpene which has been obtained from frankincense and its beneficial effects on neurodegenerative disorders such as Alzheimer’s disease (AD) have been addressed.
Methods: In the present study, thermodynamic and kinetic aspects of BBA interaction with Tau protein as one of the important proteins involved in AD in the absence and presence of glucose has been investigated using surface plasmon resonance (SPR) method. Tau protein was immobilized onto the carboxy methyl dextran chip and its binding interactions with BBA were studied at physiological pH at various temperatures. Glucose interference with these interactions was also investigated.
Results: Results showed that BBA forms a stable complex with Tau (KD=8.45×10-7 M) at 298 K. Molecular modeling analysis showed a hydrophobic interaction between BBA and HVPGGG segment of R2 and R4 repeated domains of Tau.
Conclusion: The binding affinity increased by temperature enhancement, while it decreased significantly in the presence of glucose. Both association and dissociation of the BBA-Tau complex were accompanied with an entropic activation barrier; however, positive enthalpy and entropy changes revealed that hydrophobic bonding is the main force involved in the interaction.