3IFB

NMR STUDY OF HUMAN INTESTINAL FATTY ACID BINDING PROTEIN

Summary for 3IFB

• Entry DOI: 10.2210/pdb3ifb/pdb
• Descriptor: INTESTINAL FATTY ACID BINDING PROTEIN (1 entity in total)
• Functional Keywords: fatty acid binding protein, intracellular lipid binding protein, fatty acid binding, single base polymorphism, lipid binding protein
• Biological source: Homo sapiens (human)
• Cellular location: Cytoplasm: P12104
• Total number of polymer chains: 1
• Total formula weight: 15098.04

Authors

Zhang, F.,Luecke, C.,Baier, L.J.,Sacchettini, J.C.,Hamilton, J.A. (deposition date: 1998-10-16, release date: 1998-10-21, Last modification date: 2023-12-27)

Primary citation

Zhang, F.,Lucke, C.,Baier, L.J.,Sacchettini, J.C.,Hamilton, J.A.
Solution structure of human intestinal fatty acid binding protein: implications for ligand entry and exit.
J.Biomol.NMR, 9:213-228, 1997

PubMed Abstract: The human intestinal fatty acid binding protein (I-FABP) is a small (131 amino acids) protein which binds dietary long-chain fatty acids in the cytosol of enterocytes. Recently, an alanine to threonine substitution at position 54 in I-FABP has been identified which affects fatty acid binding and transport, and is associated with the development of insulin resistance in several populations including Mexican-Americans and Pima Indians. To investigate the molecular basis of the binding properties of I-FABP, the 3D solution structure of the more common form of human I-FABP (Ala54) was studied by multidimensional NMR spectroscopy. Recombinant I-FABP was expressed from E. coli in the presence and absence of 15N-enriched media. The sequential assignments for non-delipidated I-FABP were completed by using 2D homonuclear spectra (COSY, TOCSY and NOESY) and 3D heteronuclear spectra (NOESY-HMQC and TOCSY-HMQC). The tertiary structure of human I-FABP was calculated by using the distance geometry program DIANA based on 2519 distance constraints obtained from the NMR data. Subsequent energy minimization was carried out by using the program SYBYL in the presence of distance constraints. The conformation of human I-FABP consists of 10 antiparallel beta-strands which form two nearly orthogonal beta-sheets of five strands each, and two short alpha-helices that connect the beta-strands A and B. The interior of the protein consists of a water-filled cavity between the two beta-sheets. The NMR solution structure of human I-FABP is similar to the crystal structure of rat I-FABP. The NMR results show significant conformational variability of certain backbone segments around the postulated portal region for the entry and exit of fatty acid ligand.

PubMed: 9204553
DOI: 10.1023/A:1018666522787

Experimental method

SOLUTION NMR