Acidic residue modifications restore chaperone activity of beta-casein interacting with lysozyme

作者：Moosavi Movahedi A A^*; Rajabzadeh H; Amani M; Nourouzian D; Zare K; Hadi H; Sharifzadeh A; Poursasan N; Ahmad F; Sheibani N

来源：International Journal of Biological Macromolecules, 2011, 49(4): 616-621.

DOI：10.1016/j.ijbiomac.2011.06.020

• Modified beta-casein
• Lysozyme
• Hydrophobicity
• Woodward's Reagent K
• Electrostatic potential
• Accessible surface area

An important factor in medicine and related industries is the use of chaperones to reduce protein aggregation. Here we show that chaperone ability is induced in beta-casein by modification of its acidic residues using Woodward's Reagent K (WRK). Lysozyme at pH 7.2 was used as a target protein to study beta-casein chaperone activities. The mechanism for chaperone activity of the modified beta-casein was determined using UV-vis absorbencies, fluorescence spectroscopy, differential scanning calorimetry and theoretical calculations. Our results indicated that the beta-casein destabilizes the lysozyme and increases its aggregation rate. However, WRK-ring sulfonate anion modifications enhanced the hydrophobicity of beta-casein resulting in its altered net negative charge upon interactions with lysozyme. The reversible stability of lysozyme increased in the presence of WRK-modified beta-casein, and hence its aggregation rate decreased. These results demonstrate the enhanced chaperone activity of modified beta-casein and its protective effects on lysozyme refolding.

• 出版日期2011-11-1