2ifb
From Proteopedia
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CRYSTAL STRUCTURE OF RAT INTESTINAL FATTY-ACID-BINDING PROTEIN. REFINEMENT AND ANALYSIS OF THE ESCHERICHIA COLI-DRIVED PROTEIN WITH BOUND PALMITATE
Overview
Rat intestinal fatty-acid-binding protein (I-FABP) is a small (15,124 Mr), cytoplasmic polypeptide that binds long-chain fatty acids in a, non-covalent fashion. I-FABP is a member of a family of intracellular, binding proteins that are thought to participate in the uptake, transport, and/or metabolic targeting of hydrophobic ligands. The crystal structure, of Escherichia coli-derived rat I-FABP with a single molecule of bound, palmitate has been refined to 2 A resolution using a combination of, least-squares methods, energy refinement and molecular dynamics. The, combined methods resulted in a model with a crystallographic R-factor of, 17.8% (7775 reflections, sigma greater than 2.0), root-mean-square bond, length deviation of 0.009 A and root-mean-square bond angle deviation of, 2.85 degrees. I-FABP contains ten antiparallel beta-strands organized into, two approximately orthogonal, beta-sheets. The hydrocarbon tail of its, single C16:0 ligand is present in a well-ordered, distinctively bent, conformation. The carboxylate group of the fatty acid is located in the, interior of I-FABP and forms a unique "quintet" of electrostatic, interactions involving Arg106; Gln 115, and two solvent molecules. The, hydrocarbon tail is bent with a slight left-handed helical twist from the, carboxylate group to C-16. The bent methylene chain resides in a "cradle", formed by the side-chains of hydrophobic, mainly aromatic, amino acid, residues. The refined molecular model of holo-I-FABP suggests several, potential locations for entry and exiting of the fatty acid.
About this Structure
2IFB is a Single protein structure of sequence from Rattus norvegicus with PLM as ligand. Full crystallographic information is available from OCA.
Reference
Crystal structure of rat intestinal fatty-acid-binding protein. Refinement and analysis of the Escherichia coli-derived protein with bound palmitate., Sacchettini JC, Gordon JI, Banaszak LJ, J Mol Biol. 1989 Jul 20;208(2):327-39. PMID:2671390
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