Interaction of prodigiosin with HSA and β-Lg: Spectroscopic and molecular docking studies
Banafsheh Rastegari, Hamid Reza Karbalaei-Heidari, Reza Yousefi, Sedigheh Zeinali, Masoud Nabavizadeh
Bioorganic & Medicinal Chemistry
Human serum albumin (HSA) and bovine β-lactoglobulin (β-Lg) are both introduced as blood and oral carrier scaffolds with high affinity for a wide range of pharmaceutical compounds. Prodigiosin, a natural three pyrrolic compound produced by Serratia marcescens, exhibits many pharmaceutical properties associated with health benefits. In the present study, the interaction of prodigiosin with HSA and β-Lg was investigated using fluorescence spectroscopy, circular dichroism (CD) and computational docking. Prodigiosin interacts with the Sudlow’s site I of HSA and the calyx of β-Lg with association constant of 4.41 × 104 and 1.99 × 104 M−1 to form 1:1 and 2:3 complexes at 300 K, respectively. The results indicated that binding of prodigiosin to HSA and β-Lg caused strong fluorescence quenching of both proteins through static quenching mechanism. Electrostatic and hydrophobic interactions are the major forces in the stability of PG–HSA complex with enthalpy- and entropy-driving mode, although the formation of prodigiosin–β-Lg complex is entropy-driven hydrophobic associations. CD spectra showed slight conformational changes in both proteins due to the binding of prodigiosin. Moreover, the ligand displacement assay, pH-dependent interaction and protein–ligand docking study confirmed that the prodigiosin binds to residues located in the subdomain IIA and IIIA of HSA and central calyx of β-Lg.
Circular dichroism, Secondary structure, Ligand binding, Biochemistry, Pharmaceutical