title: Calorimetric and spectroscopic investigations of β-lactoglobulin upon interaction with copper ion.
abstract: The effect of copper(II) ions (Cu(+2)) on the structure of β-lactoglobulin (β-lg) was investigated spectroscopically using UV-visible, fluorescence and circular dichroism (CD) and calorimetrically using isothermal titration calorimetry (ITC), at different temperatures. Results of the UV-visible studies showed that adding Cu(+2) to β-lg solution caused increasing turbidity, indicative of protein aggregation. It was noticeable that the rate of increasing turbidity was directly proportional to increasing temperature. The far-UV CD studies displayed that the Cu(+2) cannot induce any significant changes in the secondary structures of β-lg at different temperatures. Also, the ITC data indicated that the binding process of Cu(+2) to β-lg is mainly entropically driven. The results highlight that copper ions cause the tertiary structure of β-lg to change and induce a slightly open structure leading to the formation of supramolecular aggregates in β-lg which may result in the reduced allergenicity of β-lg and its increased use in industrial applications.
authors.affiliation: Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran. divsalar@ibb.ut.ac.ir
authors.forename: Adeleh
authors.initials: A
authors.lastname: Divsalar
authors.forename: Sajedeh Ebrahim
authors.initials: SE
authors.lastname: Damavandi
authors.forename: Ali Akbar
authors.initials: AA
authors.lastname: Saboury
authors.forename: Arefeh
authors.initials: A
authors.lastname: Seyedarabi
authors.forename: Ali Akbar
authors.initials: AA
authors.lastname: Moosavi-Movahedi
mesh_terms: D002151:Calorimetry; D002413:Cations, Divalent; D002942:Circular Dichroism; D003300:Copper / Q000737:chemistry*; D007782:Lactoglobulins / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics
chemical_list: D002413:Cations, Divalent; D007782:Lactoglobulins; D003300:Copper