Binding interaction of ramipril with bovine serum albumin (BSA): Insights from multi-spectroscopy and molecular docking methods.
The binding interaction between a typical angiotensin-converting enzyme inhibitor (ACEI), ramipril, and a transport protein, bovine serum albumin (BSA), was studied in vitro using UV-vis absorption spectroscopy, steady-state fluorescence spectroscopic titration, synchronous fluorescence spectroscopy, three dimensional fluorescence spectroscopy, circular dichroism and molecular docking under the imitated physiological conditions (pH=7.4). The experimental results suggested that the intrinsic fluorescence of BSA was quenched by ramipril thought a static quenching mechanism, indicating that the stable ramipril-BSA complex was formed by the intermolecular interaction. The number of binding sites (n) and binding constant of ramipril-BSA complex were about 1 and 3.50×104M-1at 298K, respectively, suggesting that there was stronger binding interaction of ramipril with BSA. The thermodynamic parameters together with molecular docking study revealed that both van der Waal's forces and hydrogen bonding interaction dominated the formation of the ramipril-BSA complex and the binding interaction of BSA with ramipril is enthalpy-driven processes due to |ΔH°|>|TΔS°| and ΔG°<0. The spatial distance between ramipril and BSA was calculated to be 3.56nm based on Förster's non-radiative energy transfer theory. The results of the competitive displacement experiments and molecular docking confirmed that ramipril inserted into the subdomain IIA (site I) of BSA, resulting in a slight change in the conformation of BSA but BSA still retained its secondary structure α-helicity.
College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310032, China; State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, Zhejiang University of Technology, Hangzhou 310032, China. Electronic address: shijh@zjut.edu.cn.
Jie-Hua
JH
Shi
College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310032, China.
Dong-Qi
DQ
Pan
College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310032, China.
Min
M
Jiang
College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310032, China.
Ting-Ting
TT
Liu
College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310032, China.
Qi
Q
Wang
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D062105:Molecular Docking Simulation; D017257:Ramipril / Q000378:metabolism*; D012710:Serum Albumin, Bovine / Q000378:metabolism*; D013057:Spectrum Analysis / Q000379:methods*
D000806:Angiotensin-Converting Enzyme Inhibitors; D012710:Serum Albumin, Bovine; D017257:Ramipril
Bovine serum albumin; Interaction; Molecular docking; Ramipril; Spectroscopy