Spectral deciphering of the interaction between an intramolecular hydrogen bonded ESIPT drug, 3,5-dichlorosalicylic acid, and a model transport protein

Abstract

The present work demonstrates a detailed characterization of the interaction of a bio-active drug molecule 3,5-dichlorosalicyclic acid (3,5DCSA) with a model transport protein Bovine Serum Albumin (BSA). The drug molecule is a potential candidate exhibiting Excited-State Intramolecular Proton Transfer (ESIPT) reaction and the modulation of ESIPT photophysics within the bio-environment of the protein has been exploited spectroscopically to monitor the drug-protein binding interaction. Apart from evaluating the binding constant (K (±10%) = 394 M(-1)) the probable location of the neutral drug molecule within the protein cavity (hydrophobic subdomain IIA) is explored by AutoDock-based blind docking simulation. The rotational relaxation dynamics of the drug within the protein has been interpreted on the lexicon of the two-step and wobbling-in-cone model. Circular dichroism (CD) spectroscopy delineates the effect of drug binding on the protein secondary structure in terms of decrease of α-helical content of BSA with increasing drug concentration. Also the esterase activity of the drug:protein conjugate system is found to be reduced in comparison to the native protein.

Binding of an anionic fluorescent probe with calf thymus DNA and effect of salt on the probe–DNA binding: a spectroscopic and molecular docking investigation

“…7,11,53,54 In order to get insight into ANS-ctDNA interaction and hence obtain the mode of binding of the probe with DNA, knowledge of proper binding location of the ANS into the ctDNA is important. So, we have performed the docking simulation study according to the protocol described in the Experimental Section.…”

Thermodynamic investigations of ligand–protein interactions: Binding of the phenazinium dyes phenosafranin and safranin O with human serum albumin

“…Many small molecules like drugs, dyes etc. bind to cellular serum proteins to exert their adverse and normal functions and a large number of studies have been recently undertaken in this direction [1][2][3][4][5][6][7][8][9][10][11][12]. Small dye molecules can be potentially dangerous to our environment and many living objects due to toxic, carcinogenic and polluting properties, nevertheless they are being widely used in our day today life.…”

Interaction of Indole Derivative with Human Serum Albumin: A Combined Spectroscopic and Molecular Dynamics Study

“…These spectral observations suggested the induced secondary structural changes in HSA upon binding to ID. The CD results were expressed in terms of mean residue ellipticity (MRE) in deg cm 2 dmol ‐1 according to the following equation:…”