Conformational Changes of Bovine Serum Albumin Induced by Adsorption on Different Clay Surfaces: FTIR Analysis

Abstract

Interactions between proteins and clays perturb biological activity in ecosystems, particularly soil extracellular enzyme activity. The pH dependence of hydrophobic, hydrophilic, and electrostatic interactions on the adsorption of bovine serum albumin (BSA) is studied. BSA secondary structures and hydration are revealed from computation of the Amide I and II FTIR absorption profiles. The influence of ionization of Asp, Glu, and His side chains on the adsorption processes is deduced from correlation between p 2 H dependent carboxylic/carboxylate ratio and Amide band profiles. We quantify p 2 H dependent internal and external structural unfolding for BSA adsorbed on montmorillonite, which is an electronegative phyllosilicate. Adsorption on talc, a hydrophobic surface, is less denaturing. The results emphasize the importance of electrostatic interactions in both adsorption processes. In the first case, charged side chains directly influence BSA adsorption that generate the structural transition. In the second case, the forces that attract hydrophobic side chains toward the protein-clay interface are large enough to distort peripheral amphiphilic helical domains. The resulting local unfolding displaces enough internal ionized side chains to prevent them from establishing salt bridges as for BSA native structure in solution. On montmorillonite, a particular feature is a higher protonation of the Asp and Glu side chains of the adsorbed BSA than in solution, which decreases coulombic repulsion. C 2000 Academic Press

Spectroscopic investigation of the interactions between gold nanoparticles and bovine serum albumin

“…Finally, with use of the Gaussian/Lorentzian profile, each spectrum was deconvoluted into seven peaks in the 1700-1600 cm 1 region (Figure 4). According to other protein-related research, the bands can be roughly assigned as follows [42][43][44][45][46][47] antiparallel  sheet increased from 4.2% to 11.1%. The reduction in the  -helix content in favor of the  -sheet, random coil,  -antiparallel and intermolecular  -strand structure is indicative of a partial unfolding of protein in the presence of the AuNPs.…”

How enzymes are adsorbed on soil solid phase and factors limiting its activity: A Review

“…Some studies put forward that electrostatic interaction dominates protein mineral interaction (Ding and Henrichs, 2002;Servagent-Noinville et al, 2000). The mechanism of enzyme-clay mineral interaction is a complex phenomenon because enzymes are made up of amino acids with varied properties, e.g.…”

Adsorption of bovine serum albumin onto synthetic Fe-doped geomimetic chrysotile

“…These results suggest that, despite a decrease of the coating extent in the chrysotile surface at increasing Fe concentration, a stronger interaction occurred between BSA and chrysotile surfaces. Adsorption onto a charged surface rather than a neutral one emphasizes the importance of electrostatic interactions [32]. At pH ¼ 7.4 (adsorption condition), BSA was negatively charged (Z potential of 25.1 mV) [48] while the chrysotile surface was supposed to be positively charged [49].…”

“…From the second derivative of the bands, the actual half-width can be estimated, based on which a curve-fitting process was iterated to achieve the best fitted curves. The component bands were assigned on the basis of the literature data [16,[28][29][30][31][32][33].…”