1sn5

Crystal Structure of Sea Bream Transthyretin in complex with Triiodothyronine at 1.90A Resolution

spinqualitylabelsall models 1sn5, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1sn5 is a 4 chain structure with sequence from Aurata aurata. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: SO4, T3 Related: 1sn0, 1sn2 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT 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 Transthyretin (TTR) is an extracellular transport protein involved in the distribution of thyroid hormones and vitamin A. So far, TTR has only been found in vertebrates, of which piscine TTR displays the lowest sequence identity with human TTR (47%). Human and piscine TTR bind both thyroid hormones 3,5,3'-triiodo-l-thyronine (T(3)) and 3,5,3',5'-tetraiodo-l-thyronine (thyroxine, T(4)). Human TTR has higher affinity for T(4) than T(3), whereas the reverse holds for piscine TTR. X-ray structures of Sparus aurata (sea bream) TTR have been determined as the apo-protein at 1.75 A resolution and bound to ligands T(3) and T(4), both at 1.9 A resolution. The apo structure is similar to human TTR with structural changes only at beta-strand D. This strand forms an extended loop conformation similar to the one in chicken TTR. The piscine TTR.T(4) complex shows the T(4)-binding site to be similar but not identical to human TTR, whereas the TTR.T(3) complex shows the I3' halogen situated at the site normally occupied by the hydroxyl group of T(4). The significantly wider entrance of the hormone-binding channel in sea bream TTR, in combination with its narrower cavity, provides a structural explanation for the different binding affinities of human and piscine TTR to T(3) and T(4). High resolution crystal structures of piscine transthyretin reveal different binding modes for triiodothyronine and thyroxine.,Eneqvist T, Lundberg E, Karlsson A, Huang S, Santos CR, Power DM, Sauer-Eriksson AE J Biol Chem. 2004 Jun 18;279(25):26411-6. Epub 2004 Apr 13. PMID:15082720 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Transthyretin 3D structures

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