Investigation of Conformational Changes of Bovine Serum Albumin upon Binding with Benzocaine Drug: a Spectral and Computational Analysis

Abstract

Benzocaine drug (BZC) is an active component of various nonprescription drugs and used for numb teething treatments. The interaction of BZC with bovine serum albumin (BSA) has been studied using fluorescence, synchronous fluorescence, UV-Vis, circular dichroism (CD), and molecular docking analysis. The results revealed that BZC has a strong affinity to quench the intrinsic fluorescence of BSA in terms of a static quenching mechanism under physiological conditions. The fluorescence quenching data revealed that the quenching constants are (KSV) 4.10, 3.30, and 2.35 × 104 L mol−1 at 298, 304, and 310 K, respectively. The binding constants (Kb) at three different temperatures (298, 304, and 310 K) were found to be 6.02, 3.72, and 1.10 × 105 L mol−1, respectively. The thermodynamic parameters ∆H° and ∆S° have been estimated to be − 70.67 and − 128.9 J mol−1 K−1, respectively, thereby, indicating that hydrogen bonding and Van der Waals forces play major role in the interaction of BSA–BZC. Moreover, the negative values of ΔG° − 32.30, − 31.50, − 30.68 kJ mol−1 at 298, 304, 310 K, respectively, indicate the spontaneity of the interaction. FRET analysis proved high probability of energy transfer from BSA to the drug molecule. Molecular docking and displacement studies indicated that BZC was bound to the Sudlow’s site II through hydrogen bonding and Van der Waals interactions.