Investigating the Structural Dynamics Transitions of Human Adipocyte Fatty Acid Binding Protein by NMR Spectroscopy

Abstract

Adipocyte fatty acid binding protein (FABP4) is a 132-aa intracellular lipid binding protein involved in the transport of fatty acids between cell membranes and organelles. FABP4 participates in several pathways including lipolysis and lipogenesis, and is involved in lipid and energy metabolism related diseases such as diabetes. Additionally, in animal models, inhibitors of FABP4 have been found to halt the progression of diabetes that is usually concurrent with obesity. Although the structure of FABP4 has been determined using x-ray crystallography and binding to several of its hydrophobic ligands well characterized, the transitions in the structural dynamics upon ligand binding have yet to be investigated. Here, we report the results of the NMR resonance assignment of the apo form of human FABP4, and compare these results to chemical shift prediction analysis performed using SHIFTX and SPARTA. We also report spin relaxation measurements used to probe the fast (ps-ns) backbone dynamics. Finally, through NMR titrations, we are investigating the structural dynamics transitions which occur upon binding of FABP4 to its hydrophobic ligands, including several novel lipid ligands. The project is a working collaboration between St. Catherine University, the University of Minnesota, and the Minnesota NMR Center, and provides a model of conducting collaborative undergraduate research in partnership between a PUI, a major research institution, and an instrument center.