TY - JOUR

T1 - α-casein micelles-membranes interaction

T2 - Flower-like lipid protein coaggregates formation

AU - Anselmo, Sara

AU - Sancataldo, Giuseppe

AU - Foderà, Vito

AU - Vetri, Valeria

N1 - Funding Information: The authors thank the University of Palermo for financial support (FFR – PROMETA project). GS has received funding from PON AIM1809078-1 . RICS analysis was performed at the “Bioimaging and Dosimetry lab”— Advanced Technologies Network (ATeN) Center, University of Palermo. Publisher Copyright: © 2022 Elsevier B.V.

PY - 2022

Y1 - 2022

N2 - Background: Environmental conditions regulate the association/aggregation states of proteins and their action in cellular compartments. Analysing protein behaviour in presence of lipid membranes is fundamental for the comprehension of many functional and dysfunctional processes. Here, we present an experimental study on the interaction between model membranes and α-casein. α-casein is the major component of milk proteins and it is recognised to play a key role in performing biological functions. The conformational properties of this protein and its capability to form supramolecular structures, like micelles or irreversible aggregates, are key effectors in functional and pathological effects. Methods: By means of quantitative fluorescence imaging and complementary spectroscopic methods, we were able to characterise α-casein association state and the course of events induced by pH changes, which regulate the interaction of this molecule with membranes. Results: The study of these complex dynamic events revealed that the initial conformation of the protein critically regulates the fate of α-casein, size and structure of the newly formed aggregates and their effect on membrane structures. Disassembly of micelles due to modification in electrostatic interactions results in increased membrane structure rigidity which accompanies the formation of protein lipid flower-like co-aggregates with protein molecules localised in the external part. General significance: These results may contribute to the comprehension of how the initial state of a protein establishes the course of events that occur upon changes in the molecular environment. These events which may occur in cells may be essential to functional, pathological or therapeutical properties specifically associated to casein proteins.

AB - Background: Environmental conditions regulate the association/aggregation states of proteins and their action in cellular compartments. Analysing protein behaviour in presence of lipid membranes is fundamental for the comprehension of many functional and dysfunctional processes. Here, we present an experimental study on the interaction between model membranes and α-casein. α-casein is the major component of milk proteins and it is recognised to play a key role in performing biological functions. The conformational properties of this protein and its capability to form supramolecular structures, like micelles or irreversible aggregates, are key effectors in functional and pathological effects. Methods: By means of quantitative fluorescence imaging and complementary spectroscopic methods, we were able to characterise α-casein association state and the course of events induced by pH changes, which regulate the interaction of this molecule with membranes. Results: The study of these complex dynamic events revealed that the initial conformation of the protein critically regulates the fate of α-casein, size and structure of the newly formed aggregates and their effect on membrane structures. Disassembly of micelles due to modification in electrostatic interactions results in increased membrane structure rigidity which accompanies the formation of protein lipid flower-like co-aggregates with protein molecules localised in the external part. General significance: These results may contribute to the comprehension of how the initial state of a protein establishes the course of events that occur upon changes in the molecular environment. These events which may occur in cells may be essential to functional, pathological or therapeutical properties specifically associated to casein proteins.

KW - Casein

KW - Fluorescence

KW - Micelles

KW - Protein-membrane interactions

KW - RICS

U2 - 10.1016/j.bbagen.2022.130196

DO - 10.1016/j.bbagen.2022.130196

M3 - Journal article

C2 - 35724888

AN - SCOPUS:85132900368

VL - 1866

JO - B B A - General Subjects

JF - B B A - General Subjects

SN - 0304-4165

IS - 10

M1 - 130196

ER -