Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (11): 2142-2148.doi: 10.3866/PKU.WHXB201409253

• BIOPHYSICAL CHEMISTRY • Previous Articles     Next Articles

Effect of Kolavenic Acid on the Structure of Human Serum Albumin

HE Wen-Ying1, YAO Xiao-Jun2, HUA Ying-Jie1, HUANG Guo-Lei1, WU Xiu-Li1, LI Xiao-Bao3, HAN Chang-Ri3, SONG Xiao-Ping3   

  1. 1. College of Chemical and Chemical Engineering, Hainan Normal University, Haikou 571158, P. R. China;
    2. College of Chemical and Chemical Engineering, Lanzhou University, Lanzhou 730000, P. R. China;
    3. Key Laboratory of Tropical Medicimal Plant Chemistry of Ministry of Education, Hainan Normal University, Haikou 571158, P. R. China
  • Received:2014-07-01 Revised:2014-09-25 Published:2014-10-30
  • Contact: SONG Xiao-Ping E-mail:sxp628@126.com
  • Supported by:

    The project was supported by the International S&T Cooperation Program of China (2014DFA40850) and National Natural Science Foundation of China (81160391).

Abstract:

The effect of Kolavenic acid (KA), an active component isolated from the genus Polyalthia, on the structure of human serum albumin (HSA) was investigated by fluorescence polarization, synchronous fluorescence, three-dimensional (3D) fluorescence, and absorption spectroscopy in combination with molecular modeling techniques under physiological conditions. The synchronous and absorption fluorescence spectra confirmed that KA has an effect on the microenvironment around HSA in aqueous solution. The two-dimensional (2D) and 3D fluorescence spectra showed that KA could quench the intrinsic fluorescence of HSA and make its conformation change. Fluorescence polarization measurements provided useful information on the relaxation time and aggregation behavior of the complex formed between HSA and KA, and indicated that the presence of KA caused changes in the fluidity and microviscosity of HSA. The binding constants and thermodynamic parameters for KA-HSA systems were obtained under different temperatures (298, 308, and 318 K). Molecular docking showed that the KAmoiety bound to the hydrophobic cavity of HSA, and there were three hydrogenbonding interactions between KAand the Lys195 andAsp451 residues. Fluorescent displacement measurements confirmed that KA bound to HSA at site Ⅱ. In addition, the binding mechanism of KA and HSA was revealed by the physicochemical parameters at the molecular level. The results showed that the interaction between KA and HSA was strong, indicating that KA may be stored and transferred by serum albumin.

Key words: Kolavenic acid, Human serum albumin, Molecular modeling, Fluorescence spectroscopy, UV-visible absorption spectroscopy, Interaction

MSC2000: 

  • O642