Spectroscopic studies on the interaction between tetrandrine and two serum albumins by chemometrics methods

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 115; pp. 92 - 105
• Main Authors: Cheng, Zhengjun, Liu, Rong, jiang, Xiaohui
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 01-11-2013
• Subjects: Animals; Benzylisoquinolines - chemistry; Benzylisoquinolines - metabolism; Binding constants; Bovine serum albumin; Cattle; Energy Transfer; Human serum albumin; Humans; Ions; Kinetics; Least-Squares Analysis; Multivariate Analysis; Multivariate curve resolution-alternating least squares; Protein Binding; Protein Conformation; Serum Albumin - metabolism; Serum Albumin, Bovine - metabolism; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis - methods; Temperature; Tetrandrine; Thermodynamic parameters; Thermodynamics; Multivariate curve resolution-alternating least squares; Thermodynamic parameters; Bovine serum albumin; Human serum albumin; Tetrandrine; Binding constants
• ISSN: 1386-1425; 1873-3557
• DOI: 10.1016/j.saa.2013.06.007

The interactions of tetrandrine (TETD) with two serum albumins (BSA and HSA) have been investigated using multispectroscopic and chemometrics methods at different temperatures under imitated physiological conditions. These spectra data measured were further analyzed by multivariate curve resolution-alternating least squares (MCR-ALS) and the concentration profiles for three species (BSA/HSA, TETD and TETD-BSA/HSA) existed in the interaction procedure. [Display omitted]
•The binding modes of TETD and BSA/HSA have been established.•The binding sites on BSA/HSA by TETD were discussed.•MCR-ALS was applied to interpret the interaction between TETD and BSA/HSA.•Investigating the structural changes of proteins.•Further information was extracted by chemometrics methods.
The binding interactions of tetrandrine (TETD) with bovine serum albumin (BSA) and human serum albumin (HSA) have been investigated by spectroscopic methods. These experimental data were further analyzed using multivariate curve resolution-alternating least squares (MCR-ALS) method, and the concentration profiles and pure spectra for three species (BSA/HSA, TETD and TETD-BSA/HSA) existed in the interaction procedure, as well as, the apparent equilibrium constants Kapp were evaluated. The binding sites number n and the binding constants K were obtained at various temperatures. The binding distance between TETD and BSA/HSA was 1.455/1.451nm. The site markers competitive experiments indicated that TETD primarily bound to the tryptophan residue of BSA/HSA within site I. The thermodynamic parameters (ΔG, ΔH and ΔS) calculated on the basis of different temperatures revealed that the binding of TETD-BSA was mainly depended on the hydrophobic interaction strongly and electrostatic interaction, and yet the binding of TETD-HSA was strongly relied on the hydrophobic interaction. The results of synchronous fluorescence, 3D fluorescence and FT-IR spectra show that the conformation of proteins has altered in the presence of TETD. In addition, the effect of some common ions on the binding constants between TETD and proteins were also discussed.