Solution structure and backbone dynamics of human epidermal-type fatty acid-binding protein (E-FABP)

Area of Science:

• Biochemistry
• Structural Biology
• Molecular Biophysics

Background:

• Human epidermal-type fatty acid-binding protein (E-FABP) is a key intracellular lipid-binding protein involved in fatty acid signaling, cell growth, and differentiation.
• Understanding the structure-function relationship of E-FABP is crucial for elucidating its biological roles.

Purpose of the Study:

• To determine the solution structure and backbone dynamics of human E-FABP using NMR spectroscopy.
• To investigate the relationship between E-FABP's structure, dynamics, stability, and ligand-binding properties.

Main Methods:

• High-resolution multi-dimensional NMR spectroscopy was applied to unlabeled and 15N-enriched recombinant human E-FABP.
• 1H and 15N resonance assignments were completed, and 2008 distance restraints were used to obtain the 3D solution structure.
• 15N relaxation experiments (T1, T2, NOE) and hydrogen/deuterium exchange experiments were performed to analyze backbone dynamics.

Main Results:

• The 3D solution structure of E-FABP revealed a beta-barrel structure composed of 10 anti-parallel beta-strands.
• 15N relaxation data indicated uniformly low backbone mobility (S(2) > 0.8) in the nanosecond-to-picosecond timescale.
• Hydrogen/deuterium exchange experiments showed a correlation between beta-sheet stability and millisecond-to-microsecond conformational exchange.

Conclusions:

• E-FABP exhibits a stable structure with restricted backbone dynamics.
• The observed dynamics differ significantly from related FABP family members, implying specific structural and functional adaptations.
• These findings suggest a strong interdependence between E-FABP's structure, stability, and ligand-binding affinity.