1IFC

REFINEMENT OF THE STRUCTURE OF RECOMBINANT RAT INTESTINAL FATTY ACID-BINDING APOPROTEIN AT 1.2 ANGSTROMS RESOLUTION

Summary for 1IFC

• Entry DOI: 10.2210/pdb1ifc/pdb
• Descriptor: INTESTINAL FATTY ACID BINDING PROTEIN (2 entities in total)
• Functional Keywords: lipid-binding protein, lipid binding protein
• Biological source: Rattus norvegicus (Norway rat)
• Total number of polymer chains: 1
• Total formula weight: 15146.21

Authors

Scapin, G.,Gordon, J.I.,Sacchettini, J.C. (deposition date: 1991-12-19, release date: 1994-01-31, Last modification date: 2024-02-07)

Primary citation

Scapin, G.,Gordon, J.I.,Sacchettini, J.C.
Refinement of the structure of recombinant rat intestinal fatty acid-binding apoprotein at 1.2-A resolution.
J.Biol.Chem., 267:4253-4269, 1992

PubMed Abstract: The three-dimensional structure of the 131-residue rat intestinal fatty acid-binding protein, without bound ligand (apoI-FABP), has been refined with x-ray diffraction data to a nominal resolution of 1.19 A. The final model has a conventional crystallographic R-factor of 16.9% for 34,290 unique reflections [a root mean square (r.m.s.) deviation for bond length of 0.012 A and a r.m.s. deviation of 2.368 degrees for bond angles]. Ninety-two residues are present as components of the protein's 10 anti-parallel beta-strands while 14 residues are part of its two short alpha-helices. The beta-strands and alpha-helices are organized into two nearly orthogonal beta-sheets. Particular attention has been placed in defining solvent structure and the structures of discretely disordered groups in this protein. Two hundred thirty-seven solvent molecules have been identified; 24 are located within apoI-FABP. The refined model includes alternate conformers for 228 protein atoms (109 main-chain, 119 side-chain) and 63 solvent molecules. We have found several aromatic side-chains with multiple conformations located near, or in, the protein's ligand binding site. This observation, along with the fact that these side-chains have a temperature factor that is relatively higher than that of other aromatic residues, suggests that they may be involved in the process of noncovalent binding of fatty acid. The absence of a true hydrophobic core in I-FABP suggests that its structural integrity may be maintained primarily by a hydrogen bonding network involving protein and solvent atoms.

PubMed: 1740465

Experimental method

X-RAY DIFFRACTION (1.19 Å)