Journal of Biomolecular NMR

, Volume 9, Issue 3, pp 213–228

Solution structure of human intestinal fatty acid binding protein: Implications for ligand entry and exit

  • Fengli Zhang
  • Christian Lücke
  • Leslie J. Baier
  • James C. Sacchettini
  • James A. Hamilton
Article

DOI: 10.1023/A:1018666522787

Cite this article as:
Zhang, F., Lücke, C., Baier, L.J. et al. J Biomol NMR (1997) 9: 213. doi:10.1023/A:1018666522787

Abstract

The human intestinal fatty acid binding protein (I-FABP) is a small (131 amino acids) proteinwhich binds dietary long-chain fatty acids in the cytosol of enterocytes. Recently, an alanineto threonine substitution at position 54 in I-FABP has been identified which affects fatty acidbinding and transport, and is associated with the development of insulin resistance in severalpopulations including Mexican-Americans and Pima Indians. To investigate the molecularbasis of the binding properties of I-FABP, the 3D solution structure of the more commonform 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 byusing 2D homonuclear spectra (COSY, TOCSY and NOESY) and 3D heteronuclear spectra(NOESY-HMQC and TOCSY-HMQC). The tertiary structure of human I-FABP wascalculated by using the distance geometry program DIANA based on 2519 distance constraintsobtained from the NMR data. Subsequent energy minimization was carried out by using theprogram SYBYL in the presence of distance constraints. The conformation of human I-FABPconsists of 10 antiparallel β-strands which form two nearly orthogonal β-sheets offive strands each, and two short α-helices that connect the β-strands A and B. Theinterior of the protein consists of a water-filled cavity between the two β-sheets. TheNMR 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 segmentsaround the postulated portal region for the entry and exit of fatty acid ligand.

Human intestinal fatty acid binding protein Isotope enrichment Multidimensional NMR spectroscopy; Sequential assignments Solution structure 

Copyright information

© Kluwer Academic Publishers 1997

Authors and Affiliations

  • Fengli Zhang
    • 1
  • Christian Lücke
    • 2
  • Leslie J. Baier
    • 3
  • James C. Sacchettini
    • 4
  • James A. Hamilton
    • 1
  1. 1.Department of BiophysicsBoston University School of MedicineBostonU.S.A
  2. 2.Johann Wolfgang Goethe-UniversitätFrankfurt am MainGermany
  3. 3.Phoenix Epidemiology and Clinical Research BranchNIDDK, NIHPhoenixU.S.A
  4. 4.Department of Biochemistry and BiophysicsTexas A+M UniversityCollege StationU.S.A

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