title: The synergistic chaperoning operation in a Bi-chaperone system consisting of alpha-crystallin and beta-casein: bovine pancreatic insulin as the target protein.
abstract: While chaperone activity of alpha-crystallin (α-Crs) is important in maintaining lens transparency that of beta-casein (β-CN) is vital to prevent the development of corpora amylacea (accumulation of amyloid deposits in mammary glands). These two chaperone proteins are amphiphilic, each contains distinct polar and non-polar regions in the structure. While polar domain of α-Crs is highly electropositive, the counterpart domain in β-CN is strongly electronegative. In this study a Bi-chaperone system consisting of α-Crs and β-CN with different molar ratios were used to prevent the chemical-induced insulin aggregation spectroscopically. As shown, α-Crs and β-CN in the Bi-chaperone system exhibit synergistic chaperoning operation which strongly depends to the specific ratio of the chaperone components. The results of both fluorescence study and native gel electrophoresis confirmed the non-covalent interactions between α-Crs and β-CN. Consequently the synergistic activity can be explained with the possible electrostatic interactions between their polar/charged domains which bring them in close proximity, allowing their synergistic chaperoning operation in the Bi-chaperone system.
authors.affiliation: Protein Chemistry Laboratory (PCL), Department of Biology, College of Sciences, Shiraz University, Shiraz, Fars, Iran. ryousefi@shirazu.ac.ir
authors.forename: Reza
authors.initials: R
authors.lastname: Yousefi
authors.forename: Shima
authors.initials: S
authors.lastname: Jalili
mesh_terms: D000818:Animals; D002364:Caseins / Q000737:chemistry*; D002417:Cattle; D007328:Insulin / Q000737:chemistry; D018832:Molecular Chaperones / Q000737:chemistry*; D038201:alpha-Crystallins / Q000737:chemistry*
chemical_list: D002364:Caseins; D007328:Insulin; D018832:Molecular Chaperones; D038201:alpha-Crystallins