1ifb
From Proteopedia
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REFINED APOPROTEIN STRUCTURE OF RAT INTESTINAL FATTY ACID BINDING PROTEIN PRODUCED IN ESCHERICHIA COLI
Overview
Rat intestinal fatty acid binding protein (I-FABP) is a member of a family, of cytoplasmic hydrophobic ligand-binding proteins. To gain insights about, the contribution of bound fatty acid to I-FABP's conformation and, mechanism of ligand binding, we have determined the structure of, Escherichia coli-derived rat apo-I-FABP to 1.96-A resolution and compared, it to the recently refined structure of I-FABP with bound palmitate. Both, apo- and holo-I-FABP are composed primarily of anti-parallel beta-strands, which form two nearly orthogonal beta-sheets ("beta-clam"). The overall, structures of the apo- and holo-I-FABP are nearly identical, with a root, mean square (rms) difference of 0.37 A between C alpha atoms, 0.38 A, between all main-chain atoms, and 0.94 A between all side-chain atoms., However, rms differences of greater than 1.3 A were noted for the side, chains of Ile-23, Lys-27, Arg-56, Leu-72, Ala-73, and Asp-74. The space, occupied by bound ligand in the core of the holoprotein is occupied in the, apo-protein by ordered solvent molecules. This results in an increase in, the total number of internal ordered solvent molecules from 7 in the, holoprotein to 13 in apo-I-FABP. This finding, together with observed, differences in the side-chain orientations of two residues (Arg-56 and, Lys-27) situated over a potential opening to the cores of the apo- and, holoproteins, suggests that solvent molecules play a critical role in, ligand binding. Moreover, the data indicate that the beta-clam structure, is stable even in the absence of bound ligand.
About this Structure
1IFB is a Single protein structure of sequence from Rattus norvegicus. Full crystallographic information is available from OCA.
Reference
Refined apoprotein structure of rat intestinal fatty acid binding protein produced in Escherichia coli., Sacchettini JC, Gordon JI, Banaszak LJ, Proc Natl Acad Sci U S A. 1989 Oct;86(20):7736-40. PMID:2682622
Page seeded by OCA on Tue Nov 20 17:21:37 2007
