Comparative studies of unfolding and binding of ligands to human serum albumin in the presence of fatty acid: Spectroscopic approach

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• 作者：Ankita Varshney ; Basir Ahmad ; Rizwan Hasan Khan
• 关键词：Fatty acid ; GnHCl denaturation ; Ligand binding ; Free energy change
• 刊名：International Journal of Biological Macromolecules
• 出版年：2008
• 出版时间：1 June 2008
• 年：2008
• 卷：42
• 期：5
• 页码：483-490
• 全文大小：862 K

文摘

This study was undertaken to investigate the influence of fatty acid binding on the unfolding of HSA and how the fatty acid molecules can influence and/or compete with other ligand molecules bound to the protein. The equilibrium unfolding of fatted and fatty acid free HSA was measured by overlapping of unfolding transition curves monitored by different probes for secondary and tertiary structure and determining changes in free energy of unfolding. Proteins stability was studied by fluorescence spectroscopy, whereas conformational changes were detected by circular dichroism techniques. We have suggested a “molten globule” like intermediate state of HSA at a fairly high concentration of GnHCl (3.2 for fatty acid free and 3.6 for fatted). The free energy of stabilization () in the presence of fatty acid was found to be 900 cal mol⁻¹. We also analyze the effects of fatty acid on binding of ligands using spectroscopic technique and reported the equilibrium constants and free energies obtained from the binding and unfolding experiments.