1ie4

RAT TRANSTHYRETIN COMPLEX WITH THYROXINE (T4)

spinqualitylabelsall models 1ie4, resolution 2.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1ie4 is a 4 chain structure with sequence from Rattus norvegicus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: T44 Related: 1gke, 2rox, 1ict Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [TTHY_RAT] Thyroid hormone-binding protein. Probably transports thyroxine from the bloodstream to the brain. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The first observation of the unique environment for thyroxine (T(4)) binding in tetrameric rat transthyretin (rTTR) is reported as determined by X-ray diffraction. These data revealed different modes of hormone binding in the two unique hormone-binding sites in the rat TTR tetramer channel. Differences in the orientation of thyroxine and the position of water molecules in the two binding sites further suggest a mechanism for the docking pathway of the hormone into the channel of TTR. Crystals of the rat transthyretin-thyroxine complex are isomorphous with those reported for apo rTTR and crystallized in the tetragonal space group P4(3)2(1)2 with four independent TTR monomeric subunits in the asymmetric part of the crystal lattice. Data were collected to 2.5 A resolution and the structure was refined to R = 20.9% for 15 384 data in the resolution range 12-2.5 A. Similar to human TTR, the rat protein is also a 54 000 Da tetramer with four identical polypeptide chains of 127 amino-acid residues. Of the 22 amino-acid residues which differ between the human and rat sequences, none are in the thyroxine-binding domains. Analysis of these structural data reveals that the tertiary structure is similar to that of hTTR, with only small differences in the flexible loop regions on the surface of the structure. Conformational changes of the amino acids in the channel result in a hydrogen-bonded network that connects the two binding domains, in contrast to the hydrogen bonds formed along the tetramer interface in the apo transthyretin structure. These changes suggest a mechanism for the signal transmission between thyroxine-binding domains. Structure of rat transthyretin (rTTR) complex with thyroxine at 2.5 A resolution: first non-biased insight into thyroxine binding reveals different hormone orientation in two binding sites.,Wojtczak A, Cody V, Luft JR, Pangborn W Acta Crystallogr D Biol Crystallogr. 2001 Aug;57(Pt 8):1061-70. Epub 2001, Jul 23. PMID:11468389 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Transthyretin 3D structures

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