How the strength of proteins interactions affects the phase behavior of protein complexes.

How the protein−protein interactions affect the phase behaviour of protein complexes can afford technical support for the application of egg white protein in food industry. Here the drawing of phase diagram of ovalbumin-lysozyme (Ova-Lys) complexes was reported, and the effect of interaction between Ova and Lys on the phase behaviour of three phases (co-soluble polymers, insoluble complexes and soluble complexes) was investigated by combining experimental and computational approaches. The soluble and insoluble complexes displayed an amorphous pattern, with the insoluble complexes manifesting a cross-linked conformation. Ova and Lys exhibited strong co-localization within heteroprotein complexes, where Ova being the predominant component on the surface of the complexes. Electrostatic and hydrogen bonding interactions were the main driving forces to afford co-soluble polymers, while electrostatic, hydrogen bonding and hydrophobic interactions existed in insoluble and soluble complexes. The strong force facilitated to yield insoluble complexes, while the weak force favoured to give co-soluble polymers. [Display omitted] • Influence of Ova-Lys interactions on protein complex phase behaviour was studied. • The phases included co-soluble polymers, insoluble complexes, and soluble complexes. • Electrostatic interaction was the main driving force for the phase formation. • Ova and Lys exhibited strong co-localization within the heteroprotein complexes. [ABSTRACT FROM AUTHOR]