1A57

THE THREE-DIMENSIONAL STRUCTURE OF A HELIX-LESS VARIANT OF INTESTINAL FATTY ACID BINDING PROTEIN, NMR, 20 STRUCTURES


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 23 
  • Conformers Submitted: 20 
  • Selection Criteria: FINAL PENALTY FUNCTION VALUES GREATER THAN 10.0 OR GREATER THAN TWO STANDARD DEVIATIONS FROM THE MEAN WERE OMITTED 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

The three-dimensional structure of a helix-less variant of intestinal fatty acid-binding protein.

Steele, R.A.Emmert, D.A.Kao, J.Hodsdon, M.E.Frieden, C.Cistola, D.P.

(1998) Protein Sci. 7: 1332-1339

  • DOI: 10.1002/pro.5560070609

  • PubMed Abstract: 
  • Intestinal fatty acid-binding protein (I-FABP) is a cytosolic 15.1-kDa protein that appears to function in the intracellular transport and metabolic trafficking of fatty acids. It binds a single molecule of long-chain fatty acid in an enclosed cavity ...

    Intestinal fatty acid-binding protein (I-FABP) is a cytosolic 15.1-kDa protein that appears to function in the intracellular transport and metabolic trafficking of fatty acids. It binds a single molecule of long-chain fatty acid in an enclosed cavity surrounded by two five-stranded antiparallel beta-sheets and a helix-turn-helix domain. To investigate the role of the helical domain, we engineered a variant of I-FABP by deleting 17 contiguous residues and inserting a Ser-Gly linker (Kim K et al., 1996, Biochemistry 35:7553-7558). This variant, termed delta17-SG, was remarkably stable, exhibited a high beta-sheet content and was able to bind fatty acids with some features characteristic of the wild-type protein. In the present study, we determined the structure of the delta17-SG/palmitate complex at atomic resolution using triple-resonance 3D NMR methods. Sequence-specific 1H, 13C, and 15N resonance assignments were established at pH 7.2 and 25 degrees C and used to define the consensus 1H/13C chemical shift-derived secondary structure. Subsequently, an iterative protocol was used to identify 2,544 NOE-derived interproton distance restraints and to calculate its tertiary structure using a unique distance geometry/simulated annealing algorithm. In spite of the sizable deletion, the delta17-SG structure exhibits a backbone conformation that is nearly superimposable with the beta-sheet domain of the wild-type protein. The selective deletion of the alpha-helical domain creates a very large opening that connects the interior ligand-binding cavity with exterior solvent. Unlike wild-type I-FABP, fatty acid dissociation from delta17-SG is structurally and kinetically unimpeded, and a protein conformational transition is not required. The delta17-SG variant of I-FABP is the only wild-type or engineered member of the intracellular lipid-binding protein family whose structure lacks alpha-helices. Thus, delta17-SG I-FABP constitutes a unique model system for investigating the role of the helical domain in ligand-protein recognition, protein stability and folding, lipid transfer mechanisms, and cellular function.


    Related Citations: 
    • The NMR Solution Structure of Intestinal Fatty Acid-Binding Protein Complexed with Palmitate: Application of a Novel Distance Geometry Algorithm
      Hodsdon, M.E.,Ponder, J.W.,Cistola, D.P.
      (1996) J.Mol.Biol. 264: 585
    • Discrete Backbone Disorder in the Nuclear Magnetic Resonance Structure of Apo Intestinal Fatty Acid-Binding Protein: Implications for the Mechanism of Ligand Entry
      Hodsdon, M.E.,Cistola, D.P.
      (1997) Biochemistry 36: 1450
    • Intestinal Fatty Acid-Binding Protein: The Structure and Stability of a Helix-Less Variant
      Kim, K.,Cistola, D.P.,Frieden, C.
      (1996) Biochemistry 35: 7553
    • Fatty Acid Interactions with a Helix-Less Variant of Intestinal Fatty Acid-Binding Protein
      Cistola, D.P.,Kim, K.,Rogl, H.,Frieden, C.
      (1996) Biochemistry 35: 7559


    Organizational Affiliation

    Department of Biochemistry & Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
INTESTINAL FATTY ACID-BINDING PROTEIN
A
116Rattus norvegicusGene Names: Fabp2 (Fabpi)
Find proteins for P02693 (Rattus norvegicus)
Go to UniProtKB:  P02693
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 23 
  • Conformers Submitted: 20 
  • Selection Criteria: FINAL PENALTY FUNCTION VALUES GREATER THAN 10.0 OR GREATER THAN TWO STANDARD DEVIATIONS FROM THE MEAN WERE OMITTED 
  • Olderado: 1A57 Olderado

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1998-05-27
    Type: Initial release
  • Version 1.1: 2008-03-24
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance