Modulated photophysics of a cationic DNA-staining dye inside protein bovine serum albumin: study of binding interaction and structural changes of protein.
The binding affinity of cationic DNA-staining dye, propidium iodide, with transport protein, bovine serum albumin, has been explored using UV-vis absorption, fluorescence, and circular dichroism spectroscopy. Steady state and time resolved fluorescence studies authenticate that fluorescence quenching of bovine serum albumin by propidium iodide is due to bovine serum albumin-propidium iodide complex formation. Thermodynamic parameters obtained from temperature dependent spectral studies cast light on binding interaction between the probe and protein. Site marker competitive binding has been encountered using phenylbutazone and flufenamic acid for site I and site II, respectively. Energy transfer efficiency and distance between bovine serum albumin and propidium iodide have been determined using Förster mechanism. Structural stabilization or destabilization of protein by propidium iodide has been investigated by urea denaturation study. The circular dichroism study as well as FT-IR measurement demonstrates some configurational changes of the protein in presence of the dye. Docking studies support the experimental data thereby reinforcing the binding site of the probe to the subdomain IIA of bovine serum albumin.
Department of Chemistry, University of Calcutta, 92, A.P.C. Road, Kolkata 700009, India.
Anuva
A
Samanta
Department of Chemistry, University of Calcutta, 92, A.P.C. Road, Kolkata 700009, India.
Sankar
S
Jana
Department of Chemistry, University of Calcutta, 92, A.P.C. Road, Kolkata 700009, India.
Debarati
D
Ray
Department of Chemistry, University of Calcutta, 92, A.P.C. Road, Kolkata 700009, India. Electronic address: nguchhait@yahoo.com.
Nikhil
N
Guchhait
D000818:Animals; D016880:Anisotropy; D001665:Binding Sites; D001667:Binding, Competitive; D002021:Buffers; D002412:Cations; D002417:Cattle; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry*; D004735:Energy Transfer; D007700:Kinetics; D008024:Ligands; D062105:Molecular Docking Simulation; D055585:Physical Phenomena; D011419:Propidium / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D055550:Protein Stability; D012710:Serum Albumin, Bovine / Q000737:chemistry* / Q000378:metabolism*; D012997:Solvents / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013194:Staining and Labeling; D013696:Temperature; D013997:Time Factors
D002021:Buffers; D002412:Cations; D008024:Ligands; D012997:Solvents; D012710:Serum Albumin, Bovine; D011419:Propidium; D004247:DNA
Bovine serum albumin; Chemical denaturation; Circular dichroism; Fluorescence resonance energy transfer; Propidium iodide; Site marker