Interaction and self-assembly between alpha-lactalbumin and lysozyme : structures and mechanism
Résumé
Self-assembling food proteins offer great potential as scaffolds for building bio-inspired
materials and controlled development of supramolecular structures with new functionalities.
We have conducted an exhaustive study on the interaction and self-assembly occurring
between a-lactalbumin and lysozyme, two homologous oppositely charged globular proteins.
Under controlled physico-chemical conditions, we showed that the self-assembly process
between these two proteins can be oriented towards the formation of original spherical
particles of about 2-3 μm. The mechanism behind such protein self-assembly and the
properties of formed microspheres were further investigated. In this communication, we will
address first the initial step of the interaction leading to the formation of heterodimers as
assessed by fluorescence techniques [1]. The propensity of formed heterodimers to further
self assemble into supramolecular structures is discussed on the light of subtle conformational
change occurring on a-lactalbumin and consequently on formed heterodimers according to
the temperature and the presence of calcium ions [2, 3]. Secondly, we will report on the main
properties of formed microspheres as revealed by microscopic techniques in particular how
both proteins are arranged into formed supra-molecular structures. Finally, based on kinetic
studies, we will propose evidences that the formation of α-Lactalbumin/Lysozyme
microspheres follows an “aggregation–reorganisation” mechanism.