title: Stability and gelation behavior of bovine serum albumin pre-aggregates in the presence of calcium chloride.
abstract: We study, using wide-angle and small-angle light scattering techniques, the stability and aggregation/gelation behaviors of denatured filamentous bovine serum albumin pre-aggregates (BSA-PAs), induced by CaCl(2). It is observed that transparent filamentous gels can be formed not only at low CaCl(2) concentrations but also at high CaCl(2) concentrations, while turbid gels are obtained at intermediate CaCl(2) concentrations. Although the filamentous gels at low CaCl(2) concentrations and the turbid gels at intermediate CaCl(2) concentrations are consistent with the literature observations, the filamentous gels at high CaCl(2) concentrations have to be explained by different mechanisms. The latter is attributed to the repulsive hydration interactions originating from increased surface dipoles generated by counterion binding. Since such surface dipole-induced hydration is very short-range and occurs mainly on charged or polar patches of proteins (thus protected from aggregation), the aggregation of the filamentous BSA-PAs at hydrophobic patches at the two ends is still possible, leading to formation of the filamentous gels.
authors.affiliation: Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland. hua.wu@chem.ethz.ch
authors.forename: Hua
authors.initials: H
authors.lastname: Wu
authors.forename: Paolo
authors.initials: P
authors.lastname: Arosio
authors.forename: Olga Gennadievna
authors.initials: OG
authors.lastname: Podolskaya
authors.forename: Dan
authors.initials: D
authors.lastname: Wei
authors.forename: Massimo
authors.initials: M
authors.lastname: Morbidelli
mesh_terms: D000818:Animals; D002122:Calcium Chloride / Q000737:chemistry*; D002417:Cattle; D005782:Gels / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D012710:Serum Albumin, Bovine / Q000737:chemistry* / Q000378:metabolism
chemical_list: D005782:Gels; D012710:Serum Albumin, Bovine; D002122:Calcium Chloride