A comparative study on intrinsic fluorescence of BSA and lysozyme proteins in presence of different divalent ions from their solution and thin film conformations

Abstract

Optical emission behaviours of lysozyme and bovine serum albumin, from bulk and thin film geometry, were studied in the presence of three different divalent ions (Mg , Ca or Ba ) using different spectroscopic [steady-state fluorescence, UV-Vis and Fourier transform infra-red (FTIR)] techniques. Additionally, protein thin films on silicon surfaces were prepared and morphological studies were carried out using atomic force microscopy. Dynamic quenching was mainly identified for both proteins in the presence of Mg , Ca and Ba ions. The molecular conformation of the proteins was modified in thin films compared with that in solution, consequently quenching efficiencies also varied. ATR-FTIR studies confirmed the conformational changes of proteins in the presence of all divalent ions. All metal ions used were divalent in nature and belonged to the same group of the periodic table but, depending on their individual characteristics such as electron affinity, ionic radius, etc., the magnitude of the protein and hydrated ion interaction varied and accordingly the quenching efficiency was modified. Quenching was maximum for Ca ions, followed by the other two ions. Our study clearly illustrates the geometry-dependent physical and biological functions of proteins.

Albumin/Thiacalix[4]arene Nanoparticles as Potential Therapeutic Systems: Role of the Macrocycle for Stabilization of Monomeric Protein and Self-Assembly with Ciprofloxacin

“…A decrease in the slope of the straight lines with increasing temperature from 278 K to 308 K indicates a static quenching mechanism. It should be noted that in a few publications only dynamic quenching mechanism is noted for BSA in the presence of various binding agents [ 47 , 48 ]. However, in other works a static mechanism is also described [ 49 , 50 , 51 ].…”

Hydration and Charge-Transfer Effects of Alkaline Earth Metal Ions Binding to a Carboxylate Anion, Phosphate Anion, and Guanine Nucleobase

“…Biomolecules, such as proteins, peptides, and DNA, can be combined with nanoscale materials to create nanoscale devices with applications in energy, catalysis, medicine, and electronics. − DNA is of particular interest due to its structural, electronic, and optical properties. For example, DNA-based nanodevices have applications in imaging and sensing, − drug delivery, − energy conversion, , and electronics. , Metal ions also play an important role in nanoscale devices and are used to quench spectroscopic signals, , mediate adsorption and self-assembly, − and control physical properties of nanoscale materials. − In many of these applications, alkaline earth metal ions demonstrate ion-specific effects, where the identity of the ion affects the properties of the nanoscale device. ,,, For example, Ca 2+ ions mediate DNA adsorption to anionic lipid monolayers and bilayers, − , which have implications in the development of tunable, nontoxic, and efficient drug delivery systems. , However, when Ca 2+ is replaced with Mg 2+ or Ba 2+ , DNA adsorption is altered . Alkaline earth metal ions also display ion-specific effects when mediating DNA adsorption to graphene oxide and polydopamine nanoparticles .…”

“…For example, DNA-based nanodevices have applications in imaging and sensing, 4−12 drug delivery, 13−16 energy conversion, 17,18 and electronics. 19,20 Metal ions also play an important role in nanoscale devices and are used to quench spectroscopic signals, 12,21 mediate adsorption and self-assembly, 22−27 and control physical properties of nanoscale materials. 28−30 In many of these applications, alkaline earth metal ions demonstrate ion-specific effects, where the identity of the ion affects the properties of the nanoscale device.…”

“…28−30 In many of these applications, alkaline earth metal ions demonstrate ion-specific effects, where the identity of the ion affects the properties of the nanoscale device. 21,22,27,29 For example, Ca 2+ ions mediate DNA adsorption to anionic lipid monolayers and bilayers, [22][23][24][25]31 which have implications in the development of tunable, nontoxic, and efficient drug delivery systems. 32,33 However, when Ca 2+ is replaced with Mg 2+ or Ba 2+ , DNA adsorption is altered.…”