title: The Effect of Attractive Interactions and Macromolecular Crowding on Crystallins Association.
abstract: In living systems proteins are typically found in crowded environments where their effective interactions strongly depend on the surrounding medium. Yet, their association and dissociation needs to be robustly controlled in order to enable biological function. Uncontrolled protein aggregation often causes disease. For instance, cataract is caused by the clustering of lens proteins, i.e., crystallins, resulting in enhanced light scattering and impaired vision or blindness. To investigate the molecular origins of cataract formation and to design efficient treatments, a better understanding of crystallin association in macromolecular crowded environment is needed. Here we present a theoretical study of simple coarse grained colloidal models to characterize the general features of how the association equilibrium of proteins depends on the magnitude of intermolecular attraction. By comparing the analytic results to the available experimental data on the osmotic pressure in crystallin solutions, we identify the effective parameters regimes applicable to crystallins. Moreover, the combination of two models allows us to predict that the number of binding sites on crystallin is small, i.e. one to three per protein, which is different from previous estimates. We further observe that the crowding factor is sensitive to the size asymmetry between the reactants and crowding agents, the shape of the protein clusters, and to small variations of intermolecular attraction. Our work may provide general guidelines on how to steer the protein interactions in order to control their association.
authors.affiliation: State Key Laboratory of Nonlinear Mechanics (LNM), Institute of Mechanics, Chinese Academy of Sciences, 100190, Beijing, China.
authors.forename: Jiachen
authors.initials: J
authors.lastname: Wei
authors.affiliation: International Research Center for Soft Matter, Beijing University of Chemical Technology (BUCT), 100029, Beijing, China.
authors.forename: Jure
authors.initials: J
authors.lastname: Dobnikar
authors.affiliation: The University Chemical Laboratory, University of Cambridge, Lensfield Road, CB2 1EW, Cambridge, United Kingdom.
authors.forename: Tine
authors.initials: T
authors.lastname: Curk
authors.affiliation: State Key Laboratory of Nonlinear Mechanics (LNM), Institute of Mechanics, Chinese Academy of Sciences, 100190, Beijing, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Song
mesh_terms: D000465:Algorithms; D003459:Crystallins / Q000378:metabolism*; D046911:Macromolecular Substances / Q000378:metabolism*; D008962:Models, Theoretical; D011485:Protein Binding; D012996:Solutions; D013816:Thermodynamics
chemical_list: D003459:Crystallins; D046911:Macromolecular Substances; D012996:Solutions