Conformational and structural analysis of bovine beta lactoglobulin-A upon interaction with Cr+3.
Thermodynamic studies have been made on the effect of Cr(+3) on the conformation and structure of bovine beta lactoglobulin-A, (Blg-A) in 50 mM sodium chloride solution at 27 degrees C using isothermal titration calorimetry (ITC), circular dichroism (CD) and fluorescence spectroscopy. There is a set of six identical and independent binding sites for Cr(+3) by a dissociation binding constant of 124 microM and the molar enthalpy of binding -17.8 kJ/mol. Circular dichroism studies do not show any significant change in the secondary structure of the protein after the binding of chromium ion on the Blg-A. Fluorescence spectroscopy studies do not show any considerable change in the tertiary structure of Blg-A due to the increasing of Cr(+3) in low concentration. However, occupation of fourth and fifth binding sites for chromium ions induce partially unfolding in the tertiary structure of the protein resulted from solvent - exposed hydrophobic patches on BLG-A.
Divsalar
A
A
Institute of Biochemistry and Biophysics, University of Tehran, Iran.
Saboury
A A
AA
Moosavi-Movahedi
A A
AA
D000818:Animals; D002151:Calorimetry; D002417:Cattle; D017608:Chromium Compounds / Q000737:chemistry*; D002942:Circular Dichroism; D007782:Lactoglobulins / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D009566:Nitrates / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D013050:Spectrometry, Fluorescence; D013816:Thermodynamics
D017608:Chromium Compounds; D007782:Lactoglobulins; D009566:Nitrates; C041167:chromium nitrate