Protein cold-gelation has recently received particular attention for its relevance in bio and food technology. In this work, we report a study on bovine serum albumin cold-gelation induced by copper or zinc ions. Metal-induced cold-gelation of proteins requires two steps: during the first one, the heat treatment causes protein partial unfolding and aggregation; then, after cooling the solution to room temperature, gels are formed upon the addition of metal ions. The thermally induced behaviour has been mainly investigated through different techniques: Fourier transform infrared (FTIR) spectroscopy, circular dichroism, dynamic light scattering (DLS) and rheology. Data have shown that the aggregation process is mainly due to protein conformational changes--alpha-helices into beta-aggregates-forming small aggregated structures with a mean diameter of about 20 nm a few minutes after heating. After metal ion addition, the viscoelastic properties of the gels have been investigated by rheological measurements. The behaviour of the elastic and viscous moduli as a function of time is discussed in terms of ion concentration and type. Our results show that: (1) the elastic behaviour depends on ion concentration and (2) at a given ion concentration, gels obtained in the presence of zinc exhibit an elastic value larger than that observed in the Cu(2+) case. Data suggest that cold-gelation is the result of different mechanisms: the ion-mediated protein-protein interaction and the bridging effect due to the presence of divalent ions in solution.

Navarra, G., Giacomazza, D., Leone, M., Librizzi, F., Militello, V., San Biagio, P.L. (2009). Thermal aggregation and ion-induced cold-gelation of bovine serum albumin. EUROPEAN BIOPHYSICS JOURNAL WITH BIOPHYSICS LETTERS, 2009, 437-446 [10.1007/s00249-008-0389-6].

Thermal aggregation and ion-induced cold-gelation of bovine serum albumin

NAVARRA, Giovanna;LEONE, Maurizio;MILITELLO, Valeria;
2009-01-01

Abstract

Protein cold-gelation has recently received particular attention for its relevance in bio and food technology. In this work, we report a study on bovine serum albumin cold-gelation induced by copper or zinc ions. Metal-induced cold-gelation of proteins requires two steps: during the first one, the heat treatment causes protein partial unfolding and aggregation; then, after cooling the solution to room temperature, gels are formed upon the addition of metal ions. The thermally induced behaviour has been mainly investigated through different techniques: Fourier transform infrared (FTIR) spectroscopy, circular dichroism, dynamic light scattering (DLS) and rheology. Data have shown that the aggregation process is mainly due to protein conformational changes--alpha-helices into beta-aggregates-forming small aggregated structures with a mean diameter of about 20 nm a few minutes after heating. After metal ion addition, the viscoelastic properties of the gels have been investigated by rheological measurements. The behaviour of the elastic and viscous moduli as a function of time is discussed in terms of ion concentration and type. Our results show that: (1) the elastic behaviour depends on ion concentration and (2) at a given ion concentration, gels obtained in the presence of zinc exhibit an elastic value larger than that observed in the Cu(2+) case. Data suggest that cold-gelation is the result of different mechanisms: the ion-mediated protein-protein interaction and the bridging effect due to the presence of divalent ions in solution.
2009
Navarra, G., Giacomazza, D., Leone, M., Librizzi, F., Militello, V., San Biagio, P.L. (2009). Thermal aggregation and ion-induced cold-gelation of bovine serum albumin. EUROPEAN BIOPHYSICS JOURNAL WITH BIOPHYSICS LETTERS, 2009, 437-446 [10.1007/s00249-008-0389-6].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10447/38090
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