Dynamics of Acrylodan-Labeled Bovine and Human Serum Albumin Entrapped in a Sol-Gel-Derived Biogel

Abstract

We investigate acrylodan-labeled bovine and human serum albumin (BSA-Ac and HSA-Ac) entrapped within a tetramethylorthosilane-derived biogel composite. The effects of biogel aging and drying were studied by following the acrylodan steady-state and time-resolved emission, the decay of anisotropy, and the dipolar relaxation kinetics as a function of ambient storage time. The results indicate that there is a substantial amount of nanosecond and subnanosecond dipolar relaxation within the local environment surrounding cysteine-34 in both proteins, even when they are fully encapsulated in a dry biogel. Time-resolved anisotropy experiments show that the acrylodan residue and the protein are able to undergo nanosecond motion within the biogel. The semiangle through which the acrylodan can process is the same for a freshly formed biogel and the native protein in buffer. However, once the biogel begins to dry, the semiangle increases (approximately 20 degrees and 10 degrees for BSA-Ac and HSA-Ac, respectively). This suggests that the "pocket" hosting the acrylodan reporter group opens as the biogel dries.

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 anisotropy decay for the BSA-BODIPY adducts are described by a double exponential decay law. The latter result is in line with previous work from our group 40,44,45,48,49 on cysteine-34-labeled BSA.…”

“…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.…”

Effect of Compressed CO2 on the Critical Micelle Concentration and Aggregation Number of AOT Reverse Micelles in Isooctane

“…[11][12][13] In addition, extensive research has been done to study the properties of reverse-micellar systems, such as the micropolarity and microviscosity of the water core, micellar size, and thermodynamics. Many techniques, such as UV/Vis spectroscopy, [14][15][16] FTIR spectroscopy, [17][18][19] fluorescence spectroscopy, [20,21] small-angle neutron scattering analysis, [22,23] small-angle X-ray scattering analysis, [24,25] and microcalorimetry [26][27][28] have been used to characterize reverse-micellar solutions. In recent years, microemulsions with supercritical CO 2 as the continuous phase have been studied extensively.…”

The Concentration-Dependent Distribution of Tris(4,7'-diphenyl-1,10'-phenanthroline) Ruthenium (II) within Sol-Gel-Derived Thin Films

“…Films were spin cast (2000 rpm, 30 s) onto the glass surfaces as described elsewhere. 26 The xerogel film thickness was 0.9 ± 0.1 μm. Following this deposition step, all films were initially aged under ambient conditions for 7 days.…”