Intermolecular interaction of nickel (ii) phthalocyanine tetrasulfonic acid tetrasodium salt with bovine serum albumin: A multi-technique study.

The interaction of nickel (II) phthalocyanine tetrasulfonic acid tetrasodium salt with bovine serum albumin (BSA) has been investigated by combination of fluorescence, UV-vis absorption, Fourier transform infrared (FT-IR), and circular dichorism (CD) spectroscopies as well as through molecular docking. Fluorescence quenching and absorption spectra were investigated as a mean for estimating the binding parameters. Analysis of fluorescence quenching data at different temperatures was performed in order to specify the thermodynamics parameters for interactions of phthalocyanine complex with BSA. According to experimental data it was suggested that phthalocyanine had a significant binding affinity to BSA and the process was entropy driven. Based on the results of molecular docking it was indicated that the main active binding site for this phthalocyanine complex is site I in subdomain IIA of BSA. The results provide useful information for understanding the binding mechanism of anticancer drug-albumin and gives insight into the biological activity and metabolism of the drug in blood.

An Investigation on intermolecular interaction between Bis(indolyl)methane and HSA and BSA using multi technique methods.

Bis(indolyl)methane (BIM) as one of the main active components of anticancer and antibacterial drugs is applied in medicinal and extensive area of chemistry. In this research, interaction of human and bovine serum albumins as drug carriers with BIM was investigated using spectroscopy methods and molecular modeling study. The fluorescence quenching measurements at the range of 293-310 K revealed that the quenching mechanisms for human and bovine serum albumins are static and dynamic processes, respectively. The results of quenching study were used to calculate thermodynamic parameters [Formula: see text] which indicated that the binding process occurs spontaneously and demonstrated that human and bovine serum albumins provide very good binding via hydrogen bonds, van der Waals forces, and hydrophobic interactions. Förster energy transfer measurements, synchronous fluorescence spectroscopy, and docking study showed BIM binds to the Trp residues of human and bovine serum albumin molecules in short distances. Docking study showed that BIM molecule has two hydrogen bonds and several van der Waals contacts with human and bovine serum albumins. Results of FT-IR and CD spectroscopy demonstrated that serum albumins interact with BIM molecule mainly via hydrophobic and hydrophilic interactions and the secondary structure of serum albumins are changed.

Spectroscopy and Molecular Modeling Study on Binding of Nickel Phthalocyanine to Human Serum Albumin.

The interaction of nickel tetra sulfunated phthalocyanine( NiTSPc) with human serum albumin (HSA), in 20 mM phosphate buffer pH 7.4 was investigated using advanced techniques including fluorescence, synchronous fluorescence, Fourier transform infrared (FT-IR), circular dichroism (CD) spectroscopy and molecular docking. The fluorescence quenching measurements showed a single binding site on HSA for NiTSPc with the binding constant (K_b) value equals to 1.26×106 at 25°C. The results showed that quenching mechanism of HSA by NiTSPc was of dynamic type. The results from FTIR and CD spectroscopies demonstrated that NiTSPc binds to amino acid residues of the main polypeptide chain in protein destroying the hydrogen bonding network. The corresponding thermodynamic parameters were then calculated by analysis of fluorescence data using van't Hoff plot. These data indicated that driving force for interaction was mainly hydrophobic in nature and the process was entropy driven. The information obtained from CD, FT-IR and synchronous fluorescence spectroscopies revealed that both microenvironment and conformation of HSA was changed. Molecular docking study confirmed the binding mode obtained by experimental data.