1p6p
From Proteopedia
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Crystal Structure of Toad Liver Basic Fatty Acid-Binding Protein
Overview
Two paralogous groups of fatty acid-binding proteins (FABPs) have been, described in vertebrate liver: liver FABP (L-FABP) type, extensively, characterized in mammals, and liver basic FABP (Lb-FABP) found in fish, amphibians, reptiles, and birds. We describe here the toad Lb-FABP, complete amino acid sequence, its X-ray structure to 2.5 A resolution, ligand-binding properties, and mechanism of fatty acid transfer to, phospholipid membranes. Alignment of the amino acid sequence of toad, Lb-FABP with known L-FABPs and Lb-FABPs shows that it is more closely, related to the other Lb-FABPs. Toad Lb-FABP conserves the 12, characteristic residues present in all Lb-FABPs and absent in L-FABPs and, presents the canonical fold characteristic of all the members of this, protein family. Eight out of the 12 conserved residues point to the, lipid-binding cavity of the molecule. In contrast, most of the 25 L-FABP, conserved residues are in clusters on the surface of the molecule. The, helix-turn-helix motif shows both a negative and positive electrostatic, potential surface as in rat L-FABP, and in contrast with the other FABP, types. The mechanism of anthroyloxy-labeled fatty acids transfer from, Lb-FABP to phospholipid membranes occurs by a diffusion-mediated process, as previously shown for L-FABP, but the rate of transfer is 1 order of, magnitude faster. Toad Lb-FABP can bind two cis-parinaric acid molecules, but only one trans-parinaric acid molecule while L-FABP binds two, molecules of both parinaric acid isomers. Although toad Lb-FABP shares, with L-FABP a broad ligand-binding specificity, the relative affinity is, different.
About this Structure
1P6P is a Single protein structure of sequence from Bufo arenarum. Full crystallographic information is available from OCA.
Reference
Structural and biochemical characterization of toad liver fatty acid-binding protein., Di Pietro SM, Corsico B, Perduca M, Monaco HL, Santome JA, Biochemistry. 2003 Jul 15;42(27):8192-203. PMID:12846568
Page seeded by OCA on Tue Nov 20 23:31:36 2007
