Conformational and binding properties of chicken liver basic fatty acid binding protein in solution

Area of Science:

• Biochemistry
• Protein Structure and Function
• Spectroscopy

Background:

• Fatty acid binding proteins (FABPs) are crucial for lipid metabolism.
• Understanding FABP conformation and ligand binding is key to their function.
• Chicken liver FABP serves as a model for studying these proteins.

Purpose of the Study:

• To investigate the conformation of chicken liver fatty acid binding protein.
• To characterize the binding properties of apo protein with 11-dansylamino-undecanoic acid.
• To determine the stoichiometry and binding affinity of the FABP-fatty acid complex.

Main Methods:

• Circular Dichroism (CD) spectroscopy to analyze protein conformation.
• Fluorescence spectroscopy to monitor ligand binding.
• Saturation curves to determine binding stoichiometry and constants.

Main Results:

• Precise determination of binding constant (KD = 1.0 x 10^-6 M) and 0.9:1 stoichiometry.
• FABP conformation remains stable in various organic solvent mixtures.
• No significant conformational change observed upon fatty acid binding.
• A distinct alpha-helical structure forms in 2,2,2-trifluoroethanol/water mixtures.

Conclusions:

• Chicken liver FABP exhibits stable conformation across different solvent conditions.
• Fatty acid binding does not induce major conformational changes in the protein.
• Specific solvent mixtures can induce significant structural rearrangements, forming alpha-helices.