Dynamics Surrounding Cys-34 in Native, Chemically Denatured, and Silica-Adsorbed Bovine Serum Albumin

Abstract

We report the steady-state and time-resolved fluorescence of 6-acryloyl(dimethylamino)naphthalene (acrylodan) covalently attached to Cys-34 in bovine serum albumin (BSA). For this conceptually simple system, complicated fluorescence intensity and anisotropy decay kinetics are observed. The steady-state and time-resolved results demonstrate the presence of an excited-state reaction for the BSA-acrylodan system. Additional analysis shows that dipolar relaxation of the environment surrounding acrylodan within BSA is responsible for most of the observed time-dependent evolution of the emission spectrum. The effects of temperature, chemical denaturation, and protein adsorption to a bare silica substrate are also investigated. These results demonstrate the complexity of the changes within a protein/biorecognition element that affect the signal from a single fluorescent reporter group.

The effect of buffer solution choice on protein adsorption and lubrication

“…The static adsorption [19,20] and tribological characteristics [7,[21][22][23] of albumin have been widely studied, but no work to date examines the relationship between these behaviours and the impact of buffer choice. In this study the adsorption properties of different albumin/buffer solutions were measured using a quartz crystal microbalance (QCM).…”

The Adsorption–Desorption Cycle. Reversibility of the BSA–Silica System

“…For example, the system of bovine serum albumin (BSA)-silica particles has been extensively investigated. The studies mainly concern the dependence of the adsorbed amount on the pH (10), the ionic strength (10) or presence of displacing agents (11), the kinetics of adsorption and desorption (12,13), or the structure of adsorbed protein molecules (14)(15)(16). Some general trends have emerged: BSA adsorbs on silica particles even under nonfavorable electrostatic interactions; it can be desorbed by changing the pH away from the isoelectric point of the protein and by increasing the ionic strength; the driving force of the adsorption process is related to the structural changes in the adsorbing BSA molecules.…”

Effects of fluorescent probe structure on the dynamics at cysteine-34 within bovine serum albumin: Evidence for probe-dependent modulation of the cybotactic region

“…The instrument and its capabilities have been described in detail elsewhere. 40 For static fluorescence measurements, a 450 W xenon arc lamp was used as the excitation source and single grating monochromators served as the wavelength selection devices. The excitation and emission spectral bandpasses were kept at 4 and 2 nm, respectively.…”

“…24 -27 BSA higher-order structure, structural transitions, binding, aggregation, and conformational dynamics in solution have been studied by 1 H-and 13 C-NMR, 28,29 CD, 30 ORD, 31 MS, 32 Raman, 33,34 attenuated total reflectance-Fourier transform infrared (ATR-FTIR), 35 uv-vis absorbance, 36 and fluorescence spectroscopy. [37][38][39][40][41][42][43][44][45][46][47][48][49] Despite its size and complexity, BSA contains a single free cysteine residue. 24 Located at position 34 (loop 1, domain I), this lone thiol allows one to use site-specific labeling methods to probe the BSA internal dynamics at a well-defined site and address questions about internal/local protein dynamics.…”