SANS/SAXS study of the BSA solvation properties in aqueous urea solutions via a global fit approach

Sinibaldi, Raffaele; Ortore, María Grazia; Spinozzi, Francesco; Funari, Sérgio de Souza; Teixeira, J.; Mariani, Paolo

doi:10.1007/s00249-008-0306-z

Cited by 29 publications

(33 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The fitted volume fraction values are systematically higher and the surface charges are 16 to 20 e. These results are in good agreement with our previous study using SAXS as well as those reported in the literature. 20,36 It is interesting to see that for 0.5 M NaSCN, the data with 89.4 mg mL À1 BSA are better described using a screened Coulomb potential, indicating that the surface charge still plays a role. The higher surface charge (36.6 e) can be explained by the strong salting-in effect of the thiocyanate anion.…”

Section: Protein-protein Interaction From the Second Virial Coefficientmentioning

confidence: 99%

“…[10][11][12][13][14][15][16][17][18] Using SANS combined with SAXS, Sinibaldi et al studied the solvation properties of BSA and lysozyme in urea solution and water/glycerol mixtures, respectively. 19,20 SANS and SAXS provide complementary information due to the different responses to the hydration shell surrounding proteins. The interpretation of SANS data requires knowledge of the hydration level and the H-D exchange ratio of proteins.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Hydration and interactions in protein solutions containing concentrated electrolytes studied by small-angle scattering

Zhang

Roosen-Runge

Skoda

et al. 2012

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

During protein crystallization and purification, proteins are commonly found in concentrated salt solutions. The exact interplay of the hydration shell, the salt ions, and protein-protein interactions under these conditions is far from being understood on a fundamental level, despite the obvious practical relevance. We have studied a model globular protein (bovine serum albumin, BSA) in concentrated salt solutions by small-angle neutron scattering (SANS). The data are also compared to previous studies using SAXS. The SANS results for dilute protein solutions give an averaged volume of BSA of 91,700 Å(3), which is about 37% smaller than that determined by SAXS. The difference in volume corresponds to the contribution of a hydration shell with a hydration level of 0.30 g g(-1) protein. The forward intensity I(0) determined from Guinier analysis is used to determine the second virial coefficient, A(2), which describes the overall protein interactions in solution. It is found that A(2) follows the reverse order of the Hofmeister series, i.e. (NH(4))(2)SO(4) < Na(2)SO(4) < NaOAc < NaCl < NaNO(3) < NaSCN. The dimensionless second virial coefficient B(2), corrected for the particle volume and molecular weight, has been calculated using different approaches, and shows that B(2) with corrections for hydration and the non-spherical shape of the protein describes the interactions better than those determined from the bare protein. SANS data are further analyzed in the full q-range using liquid theoretical approaches, which gives results consistent with the A(2) analysis and the experimental structure factor.

show abstract

Section: Protein-protein Interaction From the Second Virial Coefficientmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Hydration and interactions in protein solutions containing concentrated electrolytes studied by small-angle scattering

Zhang

Roosen-Runge

Skoda

et al. 2012

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…Owing to their easy accessibility, high stability, ability to bind various ligands and similarity to HSA, mammalian serum albumins, especially bovine serum albumin (BSA), are utilized in kinetic and affinity drug tests as replacements for HSA, as well as in many biochemical and pharmacological applications (Sohl & Splittgerber, 1991). BSA is used as a standard in many procedures, including vaccine preparation, as a drug by itself and as a test antigen to check the validity of assays (Leong & Fox, 1988), as a molecular-weight standard (Peters, 1996;Birnbaum & Nilsson, 1992;Sinibaldi et al, 2008) and in immunological tests such as ELISA and others (Herzog et al, 1983). ESA can replace BSA in radioimmunological and immunoenzyme analyses and its use in virological practice has been raised (Chan & Porter, 1967).…”

Section: Applications Of Albuminsmentioning

confidence: 99%

Structures of bovine, equine and leporine serum albumin

Bujacz

2012

Acta Crystallogr D Biol Crystallogr

724

554

View full text Add to dashboard Cite

Serum albumin first appeared in early vertebrates and is present in the plasma of all mammals. Its canonical structure supported by a conserved set of disulfide bridges is maintained in all mammalian serum albumins and any changes in sequence are highly correlated with evolution of the species. Previous structural investigations of mammalian serum albumins have only concentrated on human serum albumin (HSA), most likely as a consequence of crystallization and diffraction difficulties. Here, the crystal structures of serum albumins isolated from bovine, equine and leporine blood plasma are reported. The structure of bovine serum albumin (BSA) was determined at 2.47 Å resolution, two crystal structures of equine serum albumin (ESA) were determined at resolutions of 2.32 and 2.04 Å, and that of leporine serum albumin (LSA) was determined at 2.27 Å resolution. These structures were compared in detail with the structure of HSA. The ligand-binding pockets in BSA, ESA and LSA revealed different amino-acid compositions and conformations in comparison to HSA in some cases; however, much more significant differences were observed on the surface of the molecules. BSA, which is one of the most extensively utilized proteins in laboratory practice and is used as an HSA substitute in many experiments, exhibits only 75.8% identity compared with HSA. The higher resolution crystal structure of ESA highlights the binding properties of this protein because it includes several bound compounds from the crystallization solution that provide additional structural information about potential ligand-binding pockets.

show abstract

“…Small-angle scattering of x-rays (SAXS) and neutrons (SANS) are particularly suited to probe the structural properties of hydration layers around biomacromolecules in solution (28)(29)(30)(31)(32)(33). SAXS and SANS are sensitive to the electronic and nuclear scattering-length density (SLD) fluctuations, Dr, respectively, between solutes (i.e., biomacromolecules) and the bulk solvent (29).…”

Section: Introductionmentioning

confidence: 99%

“…SAXS and SANS have the advantage that the respective contribution of the hydration layer (or shell) to the overall scattering from the macromolecules varies both in magnitude and sign (34). The HS contribution has been implemented in a number of programs to back-calculate SAXS (and, more rarely, SANS) curves from atomic structures, either as a homogeneous shell of a specific thickness (30)(31)(32)35), as grid elements (36,37), as dummy atoms (38,39), as explicit water molecules (40)(41)(42)(43)(44)(45), as a density map (46,47), or by voxelization (48). Accurate description of the HS is essential for the growing field of quasiatomic protein-structure modeling from solution data (34).…”

Section: Introductionmentioning

confidence: 99%

SAXS/SANS on Supercharged Proteins Reveals Residue-Specific Modifications of the Hydration Shell

Kim

Martel

Girard

et al. 2016

Biophysical Journal

View full text Add to dashboard Cite

Water molecules in the immediate vicinity of biomacromolecules, including proteins, constitute a hydration layer characterized by physicochemical properties different from those of bulk water and play a vital role in the activity and stability of these structures, as well as in intermolecular interactions. Previous studies using solution scattering, crystallography, and molecular dynamics simulations have provided valuable information about the properties of these hydration shells, including modifications in density and ionic concentration. Small-angle scattering of x-rays (SAXS) and neutrons (SANS) are particularly useful and complementary techniques to study biomacromolecular hydration shells due to their sensitivity to electronic and nuclear scattering-length density fluctuations, respectively. Although several sophisticated SAXS/SANS programs have been developed recently, the impact of physicochemical surface properties on the hydration layer remains controversial, and systematic experimental data from individual biomacromolecular systems are scarce. Here, we address the impact of physicochemical surface properties on the hydration shell by a systematic SAXS/SANS study using three mutants of a single protein, green fluorescent protein (GFP), with highly variable net charge (þ36, À6, and À29). The combined analysis of our data shows that the hydration shell is locally denser in the vicinity of acidic surface residues, whereas basic and hydrophilic/hydrophobic residues only mildly modify its density. Moreover, the data demonstrate that the density modifications result from the combined effect of residue-specific recruitment of ions from the bulk in combination with water structural rearrangements in their vicinity. Finally, we find that the specific surface-charge distributions of the different GFP mutants modulate the conformational space of flexible parts of the protein.

show abstract

SANS/SAXS study of the BSA solvation properties in aqueous urea solutions via a global fit approach

Cited by 29 publications

References 45 publications

Hydration and interactions in protein solutions containing concentrated electrolytes studied by small-angle scattering

Hydration and interactions in protein solutions containing concentrated electrolytes studied by small-angle scattering

Structures of bovine, equine and leporine serum albumin

SAXS/SANS on Supercharged Proteins Reveals Residue-Specific Modifications of the Hydration Shell

Contact Info

Product

Resources

About