Probing the interactions of bromchlorbuterol-HCl and phenylethanolamine A with HSA by multi-spectroscopic and molecular docking technique. (June 2016)

• Record Type: Journal Article
• Authors: Bi, Shuyun; Zhao, Tingting; Zhou, Huifeng; Wang, Yu; Li, Zhihong
• Is Part Of: Journal of chemical thermodynamics. Volume 97(2016:Jun.)
• Page Start: 113
• Page End: 121
• Publication Date: 2016-06
• Subjects: Bromchlorbuterol-HCl (BCB) -- Phenylethanolamine A (PEA) -- Human serum albumin (HSA) -- Multi-spectroscopic technique -- Molecular docking; Thermodynamics -- Periodicals; Thermochemistry -- Periodicals; Thermodynamique -- Périodiques; Thermochimie -- Périodiques; Thermochemistry; Thermodynamics; Periodicals; 541.369
• DOI: 10.1016/j.jct.2016.01.004
• Languages: English
• ISSNs: 0021-9614

Abstract

Graphical abstract: Highlights: Molecular docking showed that BCB/PEA was bound at sub-domain IIA of HSA. Fluorescence lifetimes indicated that the quenching was a static quenching. CD spectra showed that BCB/PEA changed the conformation of HSA. The competitive binding between site markers and BCB/PEA was studied. The mutual influence on the two drugs binding HSA was studied. Abstract: Using fluorescence quenching, fluorescence lifetime, (UV + vis) absorption, circular dichroism (CD) and molecular docking technique, the interactions of human serum albumin (HSA) with bromchlorbuterol-HCl (BCB) and phenylethanolamine A (PEA) were investigated. The quenching rate constants and binding constants for BCB/PEA with HSA were determined at T = (292.15, 302.15 and 312.15) K respectively, which were all decreased with the increase of the temperature, showing not a dynamic quenching. The fluorescence lifetime of HSA with BCB/PEA had changed little compared to that of HSA alone ( τ 0 ), further confirming that BCB/PEA quenching of intrinsic fluorescence of HSA is a static quenching. The effects of K +, Ca 2+, Cu 2+, Zn 2+ and Fe 3+ on the binding were studied. The analysis of the thermodynamic parameters for BCB/(PEA + HSA) showed that BCB/PEA could bind to HSA via hydrophobic force. The binding distances were determined as 2.90 and 4.11 nm for (BCB + HSA) and (PEA + HSA) based on the Förster's non-radiative energy transfer theory (FRET). Synchronous fluorescence and CD spectra indicated that the conformation of HSA was changed by BCB/PEA. The competitive studies for the drug with site marker suggested that both BCB and PEA were bound at Sudlow's sites I (sub-domain IIA, also known as indometacin binding site) in HSA, and the results of the study of molecular docking also leads to the same conclusion. The competitive binding experiments for the two drugs were also performed, which further indicates that PEA and BCB could share the same binding site, and PEA has a much stronger binding capacity than BCB.