Binding between Saikosaponin C and Human Serum Albumin by Fluorescence Spectroscopy and Molecular Docking
AbstractSaikosaponin C (SSC) is one of the major active constituents of dried Radix bupleuri root (Chaihu in Chinese) that has been widely used in China to treat a variety of conditions, such as liver disease, for many centuries. The binding of SSC to human serum albumin (HSA) was explored by fluorescence, circular dichroism (CD), UV-vis spectrophotometry, and molecular docking to understand both the pharmacology and the basis of the clinical use of SSC/Chaihu. SSC produced a concentration-dependent quenching effect on the intrinsic fluorescence of HSA, accompanied by a blue shift in the fluorescence spectra. The Stern-Volmer equation showed that this quenching was dominated by static quenching. The binding constant of SSC with HSA was 3.72 × 103 and 2.99 × 103 L·mol−1 at 26 °C and 36 °C, respectively, with a single binding site on each SSC and HSA molecule. Site competitive experiments demonstrated that SSC bound to site I (subdomain IIA) and site II (subdomain IIIA) in HSA. Analysis of thermodynamic parameters indicated that hydrogen bonding and van der Waals forces were mostly responsible for SSC-HSA association. The energy transfer efficiency and binding distance between SSC and HSA was calculated to be 0.23 J and 2.61 nm at 26 °C, respectively. Synchronous fluorescence and CD measurements indicated that SSC affected HSA conformation in the SSC-HSA complex. Molecular docking supported the experimental findings in conformational changes, binding sites and binding forces, and revealed binding of SSC at the interface between subdomains IIA-IIB. View Full-Text
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Chen, Y.-C.; Wang, H.-M.; Niu, Q.-X.; Ye, D.-Y.; Liang, G.-W. Binding between Saikosaponin C and Human Serum Albumin by Fluorescence Spectroscopy and Molecular Docking. Molecules 2016, 21, 153.
Chen Y-C, Wang H-M, Niu Q-X, Ye D-Y, Liang G-W. Binding between Saikosaponin C and Human Serum Albumin by Fluorescence Spectroscopy and Molecular Docking. Molecules. 2016; 21(2):153.Chicago/Turabian Style
Chen, Yi-Cun; Wang, Hong-Mei; Niu, Qing-Xia; Ye, Dan-Yan; Liang, Guo-Wu. 2016. "Binding between Saikosaponin C and Human Serum Albumin by Fluorescence Spectroscopy and Molecular Docking." Molecules 21, no. 2: 153.
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